Merge pull request #1400 from SmileGoat/feature_dev

[speechx]add linear spectrogram feature extractor

docs/source/reference.md

@@ -35,3 +35,7 @@ We borrowed a lot of code from these repos to build `model` and `engine`, thanks
 * [librosa](https://github.com/librosa/librosa/blob/main/LICENSE.md)
 - ISC License
 - Audio feature
+
+* [ThreadPool](https://github.com/progschj/ThreadPool/blob/master/COPYING)
+- zlib License
+- ThreadPool

speechx/CMakeLists.txt

@@ -39,15 +39,40 @@ FetchContent_Declare(
   GIT_TAG "20210324.1"
 )
 FetchContent_MakeAvailable(absl)
+include_directories(${absl_SOURCE_DIR})
 
 # libsndfile
+#include(FetchContent)
+#FetchContent_Declare(
+#  libsndfile
+#  GIT_REPOSITORY "https://github.com/libsndfile/libsndfile.git"
+#  GIT_TAG "1.0.31"
+#)
+#FetchContent_MakeAvailable(libsndfile)
+
+# todo boost build
+#include(FetchContent)
+#FetchContent_Declare(
+#  Boost
+#  URL      https://boostorg.jfrog.io/artifactory/main/release/1.75.0/source/boost_1_75_0.zip
+#  URL_HASH SHA256=aeb26f80e80945e82ee93e5939baebdca47b9dee80a07d3144be1e1a6a66dd6a
+#)
+#FetchContent_MakeAvailable(Boost)
+#include_directories(${Boost_SOURCE_DIR})
+
+
+set(BOOST_ROOT ${fc_patch}/boost-subbuild/boost-populate-prefix/src/boost_1_75_0)
+include_directories(${fc_patch}/boost-subbuild/boost-populate-prefix/src/boost_1_75_0)
+link_directories(${fc_patch}/boost-subbuild/boost-populate-prefix/src/boost_1_75_0/stage/lib)
 include(FetchContent)
 FetchContent_Declare(
-  libsndfile
+  kenlm
-  GIT_REPOSITORY "https://github.com/libsndfile/libsndfile.git"
+  GIT_REPOSITORY "https://github.com/kpu/kenlm.git"
-  GIT_TAG "1.0.31"
+  GIT_TAG "df2d717e95183f79a90b2fa6e4307083a351ca6a"
 )
-FetchContent_MakeAvailable(libsndfile)
+FetchContent_MakeAvailable(kenlm)
+add_dependencies(kenlm Boost)
+include_directories(${kenlm_SOURCE_DIR})
 
 # gflags
 FetchContent_Declare(
@@ -65,7 +90,7 @@ FetchContent_Declare(
   URL_HASH SHA256=9e1b54eb2782f53cd8af107ecf08d2ab64b8d0dc2b7f5594472f3bd63ca85cdc
 )
 FetchContent_MakeAvailable(glog)
-include_directories(${glog_BINARY_DIR})
+include_directories(${glog_BINARY_DIR} ${glog_SOURCE_DIR}/src)
 
 # gtest
 FetchContent_Declare(googletest
@@ -93,6 +118,22 @@ add_dependencies(openfst gflags glog)
 link_directories(${openfst_PREFIX_DIR}/lib)
 include_directories(${openfst_PREFIX_DIR}/include)
 
+set(PADDLE_LIB ${fc_patch}/paddle-lib/paddle_inference)
+include_directories("${PADDLE_LIB}/paddle/include")
+set(PADDLE_LIB_THIRD_PARTY_PATH "${PADDLE_LIB}/third_party/install/")
+include_directories("${PADDLE_LIB_THIRD_PARTY_PATH}protobuf/include")
+#include_directories("${PADDLE_LIB_THIRD_PARTY_PATH}glog/include")
+#include_directories("${PADDLE_LIB_THIRD_PARTY_PATH}gflags/include")
+include_directories("${PADDLE_LIB_THIRD_PARTY_PATH}xxhash/include")
+include_directories("${PADDLE_LIB_THIRD_PARTY_PATH}cryptopp/include")
+
+link_directories("${PADDLE_LIB_THIRD_PARTY_PATH}protobuf/lib")
+#link_directories("${PADDLE_LIB_THIRD_PARTY_PATH}glog/lib")
+#link_directories("${PADDLE_LIB_THIRD_PARTY_PATH}gflags/lib")
+link_directories("${PADDLE_LIB_THIRD_PARTY_PATH}xxhash/lib")
+link_directories("${PADDLE_LIB_THIRD_PARTY_PATH}cryptopp/lib")
+link_directories("${PADDLE_LIB}/paddle/lib")
+
 add_subdirectory(speechx)
 
 #openblas

speechx/speechx/CMakeLists.txt

@@ -4,11 +4,43 @@ project(speechx LANGUAGES CXX)
 
 link_directories(${CMAKE_CURRENT_SOURCE_DIR}/third_party/openblas)
 
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")
+
 include_directories(
 ${CMAKE_CURRENT_SOURCE_DIR}
 ${CMAKE_CURRENT_SOURCE_DIR}/kaldi
 )
 add_subdirectory(kaldi)
 
+include_directories(
+${CMAKE_CURRENT_SOURCE_DIR}
+${CMAKE_CURRENT_SOURCE_DIR}/utils
+)
+add_subdirectory(utils)
+
+include_directories(
+${CMAKE_CURRENT_SOURCE_DIR}
+${CMAKE_CURRENT_SOURCE_DIR}/frontend
+)
+add_subdirectory(frontend)
+
+include_directories(
+${CMAKE_CURRENT_SOURCE_DIR}
+${CMAKE_CURRENT_SOURCE_DIR}/nnet
+)
+add_subdirectory(nnet)
+
+include_directories(
+${CMAKE_CURRENT_SOURCE_DIR}
+${CMAKE_CURRENT_SOURCE_DIR}/decoder
+)
+add_subdirectory(decoder)
+
 add_executable(mfcc-test codelab/feat_test/feature-mfcc-test.cc)
 target_link_libraries(mfcc-test kaldi-mfcc)
+
+add_executable(linear_spectrogram_main codelab/feat_test/linear_spectrogram_main.cc)
+target_link_libraries(linear_spectrogram_main frontend kaldi-util kaldi-feat-common gflags glog)
+
+#add_executable(offline_decoder_main codelab/decoder_test/offline_decoder_main.cc)
+#target_link_libraries(offline_decoder_main nnet decoder gflags glog)

speechx/speechx/base/basic_types.h

@@ -16,7 +16,7 @@
 
 #include "kaldi/base/kaldi-types.h"
 
-#include <limits.h>
+#include <limits>
 
 typedef float               BaseFloat;
 typedef double              double64;
@@ -35,7 +35,7 @@ typedef unsigned char      uint8;
 typedef unsigned short     uint16;
 typedef unsigned int       uint32;
 
-if defined(__LP64__) && !defined(OS_MACOSX) && !defined(OS_OPENBSD)
+#if defined(__LP64__) && !defined(OS_MACOSX) && !defined(OS_OPENBSD)
 typedef unsigned long uint64;
 #else
 typedef unsigned long long uint64;

speechx/speechx/base/common.h

@@ -0,0 +1,36 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <deque>
+#include <iostream>
+#include <istream>
+#include <fstream>
+#include <map>
+#include <memory>
+#include <ostream>
+#include <set>
+#include <sstream>
+#include <stack>
+#include <string>
+#include <vector>
+#include <unordered_map>
+#include <unordered_set>
+#include <mutex>
+
+#include "base/log.h"
+#include "base/flags.h"
+#include "base/basic_types.h"
+#include "base/macros.h"

speechx/speechx/base/flags.h

@@ -0,0 +1,17 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "gflags/gflags.h"

speechx/speechx/base/log.h

@@ -0,0 +1,17 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "glog/logging.h"

speechx/speechx/base/macros.h

@@ -16,8 +16,10 @@
 
 namespace ppspeech {
 
+#ifndef DISALLOW_COPY_AND_ASSIGN
 #define DISALLOW_COPY_AND_ASSIGN(TypeName) \
   TypeName(const TypeName&) = delete;               \
   void operator=(const TypeName&) = delete
+#endif
 
 }  // namespace pp_speech

speechx/speechx/base/thread_pool.h

@@ -0,0 +1,120 @@
+// Copyright (c) 2012 Jakob Progsch, Václav Zeman
+
+// This software is provided 'as-is', without any express or implied
+// warranty. In no event will the authors be held liable for any damages
+// arising from the use of this software.
+
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+
+//   1. The origin of this software must not be misrepresented; you must not
+//   claim that you wrote the original software. If you use this software
+//   in a product, an acknowledgment in the product documentation would be
+//   appreciated but is not required.
+
+//   2. Altered source versions must be plainly marked as such, and must not be
+//   misrepresented as being the original software.
+
+//   3. This notice may not be removed or altered from any source
+//   distribution.
+// this code is from https://github.com/progschj/ThreadPool
+
+#ifndef BASE_THREAD_POOL_H
+#define BASE_THREAD_POOL_H
+
+#include <vector>
+#include <queue>
+#include <memory>
+#include <thread>
+#include <mutex>
+#include <condition_variable>
+#include <future>
+#include <functional>
+#include <stdexcept>
+
+class ThreadPool {
+public:
+    ThreadPool(size_t);
+    template<class F, class... Args>
+    auto enqueue(F&& f, Args&&... args) 
+        -> std::future<typename std::result_of<F(Args...)>::type>;
+    ~ThreadPool();
+private:
+    // need to keep track of threads so we can join them
+    std::vector< std::thread > workers;
+    // the task queue
+    std::queue< std::function<void()> > tasks;
+    
+    // synchronization
+    std::mutex queue_mutex;
+    std::condition_variable condition;
+    bool stop;
+};
+ 
+// the constructor just launches some amount of workers
+inline ThreadPool::ThreadPool(size_t threads)
+    :   stop(false)
+{
+    for(size_t i = 0;i<threads;++i)
+        workers.emplace_back(
+            [this]
+            {
+                for(;;)
+                {
+                    std::function<void()> task;
+
+                    {
+                        std::unique_lock<std::mutex> lock(this->queue_mutex);
+                        this->condition.wait(lock,
+                            [this]{ return this->stop || !this->tasks.empty(); });
+                        if(this->stop && this->tasks.empty())
+                            return;
+                        task = std::move(this->tasks.front());
+                        this->tasks.pop();
+                    }
+
+                    task();
+                }
+            }
+        );
+}
+
+// add new work item to the pool
+template<class F, class... Args>
+auto ThreadPool::enqueue(F&& f, Args&&... args) 
+    -> std::future<typename std::result_of<F(Args...)>::type>
+{
+    using return_type = typename std::result_of<F(Args...)>::type;
+
+    auto task = std::make_shared< std::packaged_task<return_type()> >(
+            std::bind(std::forward<F>(f), std::forward<Args>(args)...)
+        );
+        
+    std::future<return_type> res = task->get_future();
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex);
+
+        // don't allow enqueueing after stopping the pool
+        if(stop)
+            throw std::runtime_error("enqueue on stopped ThreadPool");
+
+        tasks.emplace([task](){ (*task)(); });
+    }
+    condition.notify_one();
+    return res;
+}
+
+// the destructor joins all threads
+inline ThreadPool::~ThreadPool()
+{
+    {
+        std::unique_lock<std::mutex> lock(queue_mutex);
+        stop = true;
+    }
+    condition.notify_all();
+    for(std::thread &worker: workers)
+        worker.join();
+}
+
+#endif

speechx/speechx/codelab/decoder_test/offline_decoder_main.cc

@@ -0,0 +1,58 @@
+// todo refactor, repalce with gtest
+
+#include "decoder/ctc_beam_search_decoder.h"
+#include "kaldi/util/table-types.h"
+#include "base/log.h"
+#include "base/flags.h"
+
+DEFINE_string(feature_respecifier, "", "test nnet prob");
+
+using kaldi::BaseFloat;
+
+void SplitFeature(kaldi::Matrix<BaseFloat> feature, 
+                  int32 chunk_size,
+                  std::vector<kaldi::Matrix<BaseFloat>> feature_chunks) {
+
+}
+
+int main(int argc, char* argv[]) {
+  gflags::ParseCommandLineFlags(&argc, &argv, false);
+  google::InitGoogleLogging(argv[0]);
+  
+  kaldi::SequentialBaseFloatMatrixReader feature_reader(FLAGS_feature_respecifier);
+
+  // test nnet_output --> decoder result
+  int32 num_done = 0, num_err = 0;
+  
+  CTCBeamSearchOptions opts;
+  CTCBeamSearch decoder(opts);
+  
+  ModelOptions model_opts;
+  std::shared_ptr<PaddleNnet> nnet(new PaddleNnet(model_opts));
+
+  Decodable decodable();
+  decodable.SetNnet(nnet);
+
+  int32 chunk_size = 0;
+  for (; !feature_reader.Done(); feature_reader.Next()) {
+    string utt = feature_reader.Key();
+    const kaldi::Matrix<BaseFloat> feature = feature_reader.Value();
+    vector<Matrix<BaseFloat>> feature_chunks;
+    SplitFeature(feature, chunk_size, &feature_chunks);  
+    for (auto feature_chunk : feature_chunks) {
+      decodable.FeedFeatures(feature_chunk);
+      decoder.InitDecoder();
+      decoder.AdvanceDecode(decodable, chunk_size);
+    }
+    decodable.InputFinished();
+    std::string result;
+    result = decoder.GetFinalBestPath();
+    KALDI_LOG << " the result of " << utt << " is " << result;
+    decodable.Reset();
+    ++num_done;
+  }
+
+  KALDI_LOG << "Done " << num_done << " utterances, " << num_err
+            << " with errors.";
+  return (num_done != 0 ? 0 : 1);
+}

speechx/speechx/codelab/feat_test/linear_spectrogram_main.cc

@@ -0,0 +1,47 @@
+// todo refactor, repalce with gtest
+
+#include "frontend/linear_spectrogram.h"
+#include "frontend/normalizer.h"
+#include "frontend/feature_extractor_interface.h"
+#include "kaldi/util/table-types.h"
+#include "base/log.h"
+#include "base/flags.h"
+#include "kaldi/feat/wave-reader.h"
+
+DEFINE_string(wav_rspecifier, "", "test wav path");
+DEFINE_string(feature_wspecifier, "", "test wav ark");
+
+int main(int argc, char* argv[]) {
+  gflags::ParseCommandLineFlags(&argc, &argv, false);
+  google::InitGoogleLogging(argv[0]);
+  
+  kaldi::SequentialTableReader<kaldi::WaveHolder> wav_reader(FLAGS_wav_rspecifier);
+  kaldi::BaseFloatMatrixWriter feat_writer(FLAGS_feature_wspecifier);
+
+  // test feature linear_spectorgram: wave --> decibel_normalizer --> hanning window -->linear_spectrogram --> cmvn
+  int32 num_done = 0, num_err = 0;
+  ppspeech::LinearSpectrogramOptions opt;
+  ppspeech::DecibelNormalizerOptions db_norm_opt;
+  std::unique_ptr<ppspeech::FeatureExtractorInterface> base_feature_extractor(
+    new ppspeech::DecibelNormalizer(db_norm_opt));
+  ppspeech::LinearSpectrogram linear_spectrogram(opt, std::move(base_feature_extractor));
+
+  for (; !wav_reader.Done(); wav_reader.Next()) {
+    std::string utt = wav_reader.Key();
+    const kaldi::WaveData &wave_data = wav_reader.Value();
+
+    int32 this_channel = 0;
+    kaldi::SubVector<kaldi::BaseFloat> waveform(wave_data.Data(), this_channel);
+    kaldi::Matrix<BaseFloat> features;
+    linear_spectrogram.AcceptWaveform(waveform);
+    linear_spectrogram.ReadFeats(&features);
+
+    feat_writer.Write(utt, features);
+    if (num_done % 50 == 0 && num_done != 0)
+    KALDI_VLOG(2) << "Processed " << num_done << " utterances";
+    num_done++;
+  }
+    KALDI_LOG << "Done " << num_done << " utterances, " << num_err
+              << " with errors.";
+    return (num_done != 0 ? 0 : 1);
+}

speechx/speechx/decoder/CMakeLists.txt

@@ -1,2 +1,10 @@
-aux_source_directory(. DIR_LIB_SRCS)
+project(decoder)
-add_library(decoder STATIC ${DIR_LIB_SRCS})
+
+include_directories(${CMAKE_CURRENT_SOURCE_DIR/ctc_decoders})
+add_library(decoder
+  ctc_beam_search_decoder.cc
+  ctc_decoders/decoder_utils.cpp
+  ctc_decoders/path_trie.cpp
+  ctc_decoders/scorer.cpp
+)
+target_link_libraries(decoder kenlm)

speechx/speechx/decoder/common.h

@@ -0,0 +1,7 @@
+#include "base/basic_types.h"
+
+struct DecoderResult {
+  BaseFloat acoustic_score; 
+  std::vector<int32> words_idx;
+  std::vector<pair<int32, int32>> time_stamp;
+};

speechx/speechx/decoder/ctc_beam_search_decoder.cc

@@ -0,0 +1,300 @@
+#include "decoder/ctc_beam_search_decoder.h"
+
+#include "base/basic_types.h"
+#include "decoder/ctc_decoders/decoder_utils.h"
+#include "utils/file_utils.h"
+
+namespace ppspeech {
+
+using std::vector;
+using FSTMATCH = fst::SortedMatcher<fst::StdVectorFst>;
+
+CTCBeamSearch::CTCBeamSearch(const CTCBeamSearchOptions& opts) :
+    opts_(opts),
+    init_ext_scorer_(nullptr), 
+    blank_id(-1),
+    space_id(-1),
+    num_frame_decoded_(0),
+    root(nullptr) {
+
+    LOG(INFO) << "dict path: " << opts_.dict_file;
+    if (!ReadFileToVector(opts_.dict_file, &vocabulary_)) {
+        LOG(INFO) << "load the dict failed";
+    }
+    LOG(INFO) << "read the vocabulary success, dict size: " << vocabulary_.size();
+
+    LOG(INFO) << "language model path: " << opts_.lm_path;
+    init_ext_scorer_ = std::make_shared<Scorer>(opts_.alpha, 
+                                                opts_.beta, 
+                                                opts_.lm_path, 
+                                                vocabulary_);
+}
+
+void CTCBeamSearch::Reset() {
+  num_frame_decoded_ = 0;
+  ResetPrefixes();
+}
+
+void CTCBeamSearch::InitDecoder() {
+    
+    blank_id = 0;
+    auto it = std::find(vocabulary_.begin(), vocabulary_.end(), " ");
+    
+    space_id = it - vocabulary_.begin();
+    // if no space in vocabulary
+    if ((size_t)space_id >= vocabulary_.size()) {
+        space_id = -2;
+    }  
+
+    ResetPrefixes();
+    
+    root = std::make_shared<PathTrie>();
+    root->score = root->log_prob_b_prev = 0.0;
+    prefixes.push_back(root.get());
+    if (init_ext_scorer_ != nullptr && !init_ext_scorer_->is_character_based()) {
+        auto fst_dict =
+            static_cast<fst::StdVectorFst *>(init_ext_scorer_->dictionary);
+        fst::StdVectorFst *dict_ptr = fst_dict->Copy(true);
+        root->set_dictionary(dict_ptr);
+        
+        auto matcher = std::make_shared<FSTMATCH>(*dict_ptr, fst::MATCH_INPUT);
+        root->set_matcher(matcher);
+    }
+}
+
+void CTCBeamSearch::Decode(std::shared_ptr<kaldi::DecodableInterface> decodable) {
+  return;
+}
+
+int32 CTCBeamSearch::NumFrameDecoded() {
+  return num_frame_decoded_;
+}
+
+// todo rename, refactor
+void CTCBeamSearch::AdvanceDecode(const std::shared_ptr<kaldi::DecodableInterface>& decodable,
+                                  int max_frames) {
+    while (max_frames > 0) {
+      vector<vector<BaseFloat>> likelihood;
+      if (decodable->IsLastFrame(NumFrameDecoded() + 1)) {
+        break;
+      }
+      likelihood.push_back(decodable->FrameLogLikelihood(NumFrameDecoded() + 1));
+      AdvanceDecoding(likelihood);
+      max_frames--;
+    }
+}
+
+void CTCBeamSearch::ResetPrefixes() {
+  for (size_t i = 0; i < prefixes.size(); i++) {
+    if (prefixes[i] != nullptr) {
+      delete prefixes[i];
+      prefixes[i] = nullptr;
+    }
+  }
+}
+
+int CTCBeamSearch::DecodeLikelihoods(const vector<vector<float>>&probs, 
+                                      vector<string>& nbest_words) {
+  kaldi::Timer timer;
+  timer.Reset();
+  AdvanceDecoding(probs);
+  LOG(INFO) <<"ctc decoding elapsed time(s) " << static_cast<float>(timer.Elapsed()) / 1000.0f;
+  return 0;
+} 
+
+vector<std::pair<double, string>> CTCBeamSearch::GetNBestPath() {
+  return get_beam_search_result(prefixes, vocabulary_, opts_.beam_size);
+}
+
+string CTCBeamSearch::GetBestPath() {
+  std::vector<std::pair<double, std::string>> result;
+  result = get_beam_search_result(prefixes, vocabulary_, opts_.beam_size);
+  return result[0].second;
+}
+
+string CTCBeamSearch::GetFinalBestPath() {
+  CalculateApproxScore();
+  LMRescore();
+  return GetBestPath();
+}
+
+void CTCBeamSearch::AdvanceDecoding(const vector<vector<BaseFloat>>& probs) {
+  size_t num_time_steps = probs.size();
+  size_t beam_size = opts_.beam_size;
+  double cutoff_prob = opts_.cutoff_prob;
+  size_t cutoff_top_n = opts_.cutoff_top_n;
+
+  vector<vector<double>> probs_seq(probs.size(), vector<double>(probs[0].size(), 0));
+
+  int row = probs.size();
+  int col = probs[0].size();
+  for(int i = 0; i < row; i++) {
+    for (int j = 0; j < col; j++){
+      probs_seq[i][j] = static_cast<double>(probs[i][j]);
+    }
+  }
+ 
+  for (size_t time_step = 0; time_step < num_time_steps; time_step++) {
+    const auto& prob = probs_seq[time_step];
+
+    float min_cutoff = -NUM_FLT_INF;
+    bool full_beam = false;
+    if (init_ext_scorer_ != nullptr) {
+      size_t num_prefixes = std::min(prefixes.size(), beam_size);
+      std::sort(prefixes.begin(), prefixes.begin() + num_prefixes,
+                prefix_compare);
+            
+      if (num_prefixes == 0) {
+        continue;
+      }
+      min_cutoff = prefixes[num_prefixes - 1]->score +
+                      std::log(prob[blank_id]) -
+                      std::max(0.0, init_ext_scorer_->beta);
+
+      full_beam = (num_prefixes == beam_size);
+    }
+        
+    vector<std::pair<size_t, float>> log_prob_idx =
+                get_pruned_log_probs(prob, cutoff_prob, cutoff_top_n);
+
+    // loop over chars
+    size_t log_prob_idx_len = log_prob_idx.size();
+    for (size_t index = 0; index < log_prob_idx_len; index++) {            
+      SearchOneChar(full_beam, log_prob_idx[index], min_cutoff);
+    } 
+
+    prefixes.clear();
+        
+    // update log probs
+    root->iterate_to_vec(prefixes);
+    // only preserve top beam_size prefixes
+    if (prefixes.size() >= beam_size) {
+      std::nth_element(prefixes.begin(),
+                       prefixes.begin() + beam_size,
+                       prefixes.end(),
+                       prefix_compare);
+      for (size_t i = beam_size; i < prefixes.size(); ++i) {
+        prefixes[i]->remove();
+      }
+    } // if 
+    num_frame_decoded_++;
+  } // for probs_seq
+}
+
+int32 CTCBeamSearch::SearchOneChar(const bool& full_beam,
+                                 const std::pair<size_t, BaseFloat>& log_prob_idx,
+                                 const BaseFloat& min_cutoff) {
+  size_t beam_size = opts_.beam_size;
+  const auto& c = log_prob_idx.first;
+  const auto& log_prob_c = log_prob_idx.second;
+  size_t prefixes_len = std::min(prefixes.size(), beam_size);
+    
+  for (size_t i = 0; i < prefixes_len; ++i) {
+    auto prefix = prefixes[i];
+    if (full_beam && log_prob_c + prefix->score < min_cutoff) {
+      break;
+    }
+
+    if (c == blank_id) {
+      prefix->log_prob_b_cur = log_sum_exp(
+                              prefix->log_prob_b_cur, 
+                              log_prob_c +
+                              prefix->score);
+      continue;
+    }
+
+    // repeated character
+    if (c == prefix->character) {
+      // p_{nb}(l;x_{1:t}) = p(c;x_{t})p(l;x_{1:t-1})
+      prefix->log_prob_nb_cur = log_sum_exp(
+                                  prefix->log_prob_nb_cur,
+                                  log_prob_c + 
+                                  prefix->log_prob_nb_prev);
+    }
+
+    // get new prefix
+    auto prefix_new = prefix->get_path_trie(c);
+    if (prefix_new != nullptr) {
+      float log_p = -NUM_FLT_INF;
+      if (c == prefix->character &&
+        prefix->log_prob_b_prev > -NUM_FLT_INF) { 
+         // p_{nb}(l^{+};x_{1:t}) = p(c;x_{t})p_{b}(l;x_{1:t-1})
+        log_p = log_prob_c + prefix->log_prob_b_prev;
+      } else if (c != prefix->character) {
+        // p_{nb}(l^{+};x_{1:t}) = p(c;x_{t}) p(l;x_{1:t-1})
+        log_p = log_prob_c + prefix->score;
+      }
+
+      // language model scoring
+      if (init_ext_scorer_ != nullptr &&
+          (c == space_id || init_ext_scorer_->is_character_based())) {
+        PathTrie *prefix_to_score = nullptr;
+        // skip scoring the space
+        if (init_ext_scorer_->is_character_based()) {
+            prefix_to_score = prefix_new;
+        } else {
+            prefix_to_score = prefix;
+        }
+
+        float score = 0.0;
+        vector<string> ngram;
+        ngram = init_ext_scorer_->make_ngram(prefix_to_score);
+        // lm score: p_{lm}(W)^{\alpha} + \beta
+        score = init_ext_scorer_->get_log_cond_prob(ngram) *
+                                init_ext_scorer_->alpha;
+        log_p += score;
+        log_p += init_ext_scorer_->beta;
+      }
+      // p_{nb}(l;x_{1:t})
+      prefix_new->log_prob_nb_cur =
+                      log_sum_exp(prefix_new->log_prob_nb_cur, 
+                                  log_p);
+    }
+  } // end of loop over prefix
+  return 0;
+}
+
+void CTCBeamSearch::CalculateApproxScore() {
+  size_t beam_size = opts_.beam_size;
+  size_t num_prefixes = std::min(prefixes.size(), beam_size);
+  std::sort(
+      prefixes.begin(), 
+      prefixes.begin() + num_prefixes, 
+      prefix_compare);
+
+  // compute aproximate ctc score as the return score, without affecting the
+  // return order of decoding result. To delete when decoder gets stable.
+  for (size_t i = 0; i < beam_size && i < prefixes.size(); ++i) {
+    double approx_ctc = prefixes[i]->score;
+    if (init_ext_scorer_ != nullptr) {
+      vector<int> output;
+      prefixes[i]->get_path_vec(output);
+      auto prefix_length = output.size();
+      auto words = init_ext_scorer_->split_labels(output);
+      // remove word insert
+      approx_ctc = approx_ctc - prefix_length * init_ext_scorer_->beta;
+      // remove language model weight:
+      approx_ctc -=
+          (init_ext_scorer_->get_sent_log_prob(words)) * init_ext_scorer_->alpha;
+    }
+    prefixes[i]->approx_ctc = approx_ctc;
+  }
+}
+
+void CTCBeamSearch::LMRescore() {
+  size_t beam_size = opts_.beam_size;
+  if (init_ext_scorer_ != nullptr && !init_ext_scorer_->is_character_based()) {
+    for (size_t i = 0; i < beam_size && i < prefixes.size(); ++i) {
+      auto prefix = prefixes[i];
+      if (!prefix->is_empty() && prefix->character != space_id) {
+        float score = 0.0;
+        vector<string> ngram = init_ext_scorer_->make_ngram(prefix);
+        score = init_ext_scorer_->get_log_cond_prob(ngram) * init_ext_scorer_->alpha;
+        score += init_ext_scorer_->beta;
+        prefix->score += score;
+      }
+    }
+  }
+}
+
+} // namespace ppspeech

speechx/speechx/decoder/ctc_beam_search_decoder.h

@@ -0,0 +1,79 @@
+#include "base/common.h"
+#include "nnet/decodable-itf.h"
+#include "util/parse-options.h"
+#include "decoder/ctc_decoders/scorer.h"
+#include "decoder/ctc_decoders/path_trie.h"
+
+#pragma once
+
+namespace ppspeech {
+
+struct CTCBeamSearchOptions {
+    std::string dict_file;
+    std::string lm_path;
+    BaseFloat alpha;
+    BaseFloat beta;
+    BaseFloat cutoff_prob;
+    int beam_size;
+    int cutoff_top_n;
+    int num_proc_bsearch;
+    CTCBeamSearchOptions() :
+        dict_file("./model/words.txt"),
+        lm_path("./model/lm.arpa"),
+        alpha(1.9f),
+        beta(5.0),
+        beam_size(300),
+        cutoff_prob(0.99f),
+        cutoff_top_n(40),
+        num_proc_bsearch(0) {
+    }
+
+    void Register(kaldi::OptionsItf* opts) {
+        opts->Register("dict", &dict_file, "dict file ");
+        opts->Register("lm-path", &lm_path, "language model file");
+        opts->Register("alpha", &alpha, "alpha");
+        opts->Register("beta", &beta, "beta");
+        opts->Register("beam-size", &beam_size, "beam size for beam search method");
+        opts->Register("cutoff-prob", &cutoff_prob, "cutoff probs");
+        opts->Register("cutoff-top-n", &cutoff_top_n, "cutoff top n");
+        opts->Register("num-proc-bsearch", &num_proc_bsearch, "num proc bsearch");
+    }
+};
+
+class CTCBeamSearch {
+ public: 
+    explicit CTCBeamSearch(const CTCBeamSearchOptions& opts);
+    ~CTCBeamSearch() {}
+    void InitDecoder();
+    void Decode(std::shared_ptr<kaldi::DecodableInterface> decodable);
+    std::string GetBestPath(); 
+    std::vector<std::pair<double, std::string>> GetNBestPath(); 
+    std::string GetFinalBestPath();
+    int NumFrameDecoded();
+    int DecodeLikelihoods(const std::vector<std::vector<BaseFloat>>&probs, 
+                          std::vector<std::string>& nbest_words);
+    void AdvanceDecode(const std::shared_ptr<kaldi::DecodableInterface>& decodable,
+                       int max_frames);
+    void Reset();
+ private:
+  void ResetPrefixes();
+  int32 SearchOneChar(const bool& full_beam,
+                      const std::pair<size_t, BaseFloat>& log_prob_idx,
+                      const BaseFloat& min_cutoff);
+  void CalculateApproxScore();
+  void LMRescore();
+  void AdvanceDecoding(const std::vector<std::vector<BaseFloat>>& probs);
+  
+  CTCBeamSearchOptions opts_;
+  std::shared_ptr<Scorer> init_ext_scorer_; // todo separate later
+  //std::vector<DecodeResult> decoder_results_;
+  std::vector<std::string> vocabulary_; // todo remove later
+  size_t blank_id;        
+  int space_id;
+  std::shared_ptr<PathTrie> root;
+  std::vector<PathTrie*> prefixes;
+  int num_frame_decoded_;
+  DISALLOW_COPY_AND_ASSIGN(CTCBeamSearch);
+};
+
+} // namespace basr

speechx/speechx/decoder/ctc_decoders

@@ -0,0 +1 @@
+../../../third_party/ctc_decoders

speechx/speechx/frontend/CMakeLists.txt

@@ -0,0 +1,8 @@
+project(frontend)
+
+add_library(frontend
+  normalizer.cc
+  linear_spectrogram.cc  
+)
+
+target_link_libraries(frontend kaldi-matrix)

speechx/speechx/frontend/fbank.h

@@ -0,0 +1,36 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// wrap the fbank feat of kaldi, todo (SmileGoat)
+
+#include "kaldi/feat/feature-mfcc.h"
+
+#incldue "kaldi/matrix/kaldi-vector.h"
+
+namespace ppspeech {
+
+class FbankExtractor : FeatureExtractorInterface {
+  public:
+    explicit FbankExtractor(const FbankOptions& opts, 
+                            share_ptr<FeatureExtractorInterface> pre_extractor);
+    virtual void AcceptWaveform(const kaldi::Vector<kaldi::BaseFloat>& input) = 0;
+    virtual void Read(kaldi::Vector<kaldi::BaseFloat>* feat) = 0;
+    virtual size_t Dim() const = 0;
+
+  private:
+     bool Compute(const kaldi::Vector<kaldi::BaseFloat>& wave,
+                  kaldi::Vector<kaldi::BaseFloat>* feat) const; 
+};
+
+}  // namespace ppspeech

speechx/speechx/frontend/feature_extractor_interface.h

@@ -0,0 +1,29 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "base/basic_types.h"
+#include "kaldi/matrix/kaldi-vector.h"
+
+namespace ppspeech {
+
+class FeatureExtractorInterface {
+  public:
+    virtual void AcceptWaveform(const kaldi::VectorBase<kaldi::BaseFloat>& input) = 0;
+    virtual void Read(kaldi::VectorBase<kaldi::BaseFloat>* feat) = 0;
+    virtual size_t Dim() const = 0;
+};
+
+}  // namespace ppspeech

speechx/speechx/frontend/linear_spectrogram.cc

@@ -0,0 +1,179 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "frontend/linear_spectrogram.h"
+#include "kaldi/base/kaldi-math.h"
+#include "kaldi/matrix/matrix-functions.h"
+
+namespace ppspeech {
+
+using kaldi::int32;
+using kaldi::BaseFloat;
+using kaldi::Vector;
+using kaldi::VectorBase;
+using kaldi::Matrix;
+using std::vector;
+
+//todo remove later
+void CopyVector2StdVector_(const VectorBase<BaseFloat>& input,
+                          vector<BaseFloat>* output) {
+  if (input.Dim() == 0) return;
+  output->resize(input.Dim());
+  for (size_t idx = 0; idx < input.Dim(); ++idx) {
+    (*output)[idx] = input(idx);
+  }
+}
+
+void CopyStdVector2Vector_(const vector<BaseFloat>& input,
+                          Vector<BaseFloat>* output) {
+  if (input.empty()) return;
+  output->Resize(input.size());
+  for (size_t idx = 0; idx < input.size(); ++idx) {
+    (*output)(idx) = input[idx];
+  }
+}
+
+LinearSpectrogram::LinearSpectrogram(
+    const LinearSpectrogramOptions& opts,
+    std::unique_ptr<FeatureExtractorInterface> base_extractor) {
+  base_extractor_ = std::move(base_extractor);
+  int32 window_size = opts.frame_opts.WindowSize();
+  int32 window_shift = opts.frame_opts.WindowShift();
+  fft_points_ = window_size;
+  hanning_window_.resize(window_size);
+
+  double a = M_2PI / (window_size - 1);
+  hanning_window_energy_ = 0;
+  for (int i = 0; i < window_size; ++i) {
+    hanning_window_[i] = 0.5 - 0.5 * cos(a * i);
+    hanning_window_energy_ += hanning_window_[i] * hanning_window_[i];
+  }
+
+  dim_ = fft_points_ / 2 + 1;  // the dimension is Fs/2 Hz
+}
+
+void LinearSpectrogram::AcceptWaveform(const VectorBase<BaseFloat>& input) {
+  base_extractor_->AcceptWaveform(input);
+}
+
+void LinearSpectrogram::Hanning(vector<float>* data) const {
+  CHECK_GE(data->size(), hanning_window_.size());
+
+  for (size_t i = 0; i < hanning_window_.size(); ++i) {
+      data->at(i) *= hanning_window_[i];
+  }
+}
+
+bool LinearSpectrogram::NumpyFft(vector<BaseFloat>* v,
+                                 vector<BaseFloat>* real,
+                                 vector<BaseFloat>* img) const {
+  Vector<BaseFloat> v_tmp;
+  CopyStdVector2Vector_(*v, &v_tmp);
+  RealFft(&v_tmp, true);
+  CopyVector2StdVector_(v_tmp, v);
+  real->push_back(v->at(0));
+  img->push_back(0);
+  for (int i = 1; i < v->size() / 2; i++) {
+    real->push_back(v->at(2 * i));
+    img->push_back(v->at(2 * i + 1));
+  }
+  real->push_back(v->at(1));
+  img->push_back(0);
+
+  return true;
+}
+
+// todo remove later
+void LinearSpectrogram::ReadFeats(Matrix<BaseFloat>* feats) {
+  Vector<BaseFloat> tmp;
+  waveform_.Resize(base_extractor_->Dim());
+  Compute(tmp, &waveform_);
+  vector<vector<BaseFloat>> result;
+  vector<BaseFloat> feats_vec; 
+  CopyVector2StdVector_(waveform_, &feats_vec);
+  Compute(feats_vec, result);
+  feats->Resize(result.size(), result[0].size());
+  for (int row_idx = 0; row_idx < result.size(); ++row_idx) {
+    for (int col_idx = 0; col_idx < result.size(); ++col_idx) {
+        (*feats)(row_idx, col_idx) = result[row_idx][col_idx];
+    }
+  }
+  waveform_.Resize(0);
+}
+
+void LinearSpectrogram::Read(VectorBase<BaseFloat>* feat) {
+  // todo
+  return;
+}
+
+// only for test, remove later
+// todo: compute the feature frame by frame.
+void LinearSpectrogram::Compute(const VectorBase<kaldi::BaseFloat>& input,
+                                VectorBase<kaldi::BaseFloat>* feature) {
+    base_extractor_->Read(feature);
+}
+
+// Compute spectrogram feat, only for test, remove later
+// todo: refactor later (SmileGoat)
+bool LinearSpectrogram::Compute(const vector<float>& wave,
+                                vector<vector<float>>& feat) {
+  int num_samples = wave.size();
+  const int& frame_length = opts_.frame_opts.WindowSize();
+  const int& sample_rate = opts_.frame_opts.samp_freq;
+  const int& frame_shift = opts_.frame_opts.WindowShift();
+  const int& fft_points = fft_points_;
+  const float scale = hanning_window_energy_ * frame_shift;
+
+  if (num_samples < frame_length) {
+          return true;
+  }
+
+  int num_frames = 1 + ((num_samples - frame_length) / frame_shift);
+  feat.resize(num_frames);
+  vector<float> fft_real((fft_points_ / 2 + 1), 0);
+  vector<float> fft_img((fft_points_ / 2 + 1), 0);
+  vector<float> v(frame_length, 0);
+  vector<float> power((fft_points / 2 + 1));
+
+  for (int i = 0; i < num_frames; ++i) {
+    vector<float> data(wave.data() + i * frame_shift,
+                       wave.data() + i * frame_shift + frame_length);
+    Hanning(&data);
+    fft_img.clear();
+    fft_real.clear();
+    v.assign(data.begin(), data.end());
+    if (NumpyFft(&v, &fft_real, &fft_img)) {
+      LOG(ERROR)<< i  << " fft compute occurs error, please checkout the input data";
+      return false;
+    }
+
+    feat[i].resize(fft_points / 2 + 1);  // the last dimension is Fs/2 Hz
+    for (int j = 0; j < (fft_points / 2 + 1); ++j) {
+      power[j] = fft_real[j] * fft_real[j] + fft_img[j] * fft_img[j];
+      feat[i][j] = power[j];
+
+      if (j == 0 || j == feat[0].size() - 1) {
+          feat[i][j] /= scale;
+      } else {
+          feat[i][j] *= (2.0 / scale);
+      }
+
+      // log added eps=1e-14
+      feat[i][j] = std::log(feat[i][j] + 1e-14);
+    }
+  }
+  return true;
+}
+
+}  // namespace ppspeech

speechx/speechx/frontend/linear_spectrogram.h

@@ -0,0 +1,50 @@
+
+#pragma once
+
+#include "frontend/feature_extractor_interface.h"
+#include "kaldi/feat/feature-window.h"
+#include "base/common.h"
+
+namespace ppspeech {
+
+struct LinearSpectrogramOptions {
+    kaldi::FrameExtractionOptions frame_opts;
+    LinearSpectrogramOptions():
+        frame_opts() {}
+
+    void Register(kaldi::OptionsItf* opts) {
+        frame_opts.Register(opts);
+    }
+};
+
+class LinearSpectrogram : public FeatureExtractorInterface {
+  public:
+    explicit LinearSpectrogram(const LinearSpectrogramOptions& opts,
+                               std::unique_ptr<FeatureExtractorInterface> base_extractor);
+    virtual void AcceptWaveform(const kaldi::VectorBase<kaldi::BaseFloat>& input);
+    virtual void Read(kaldi::VectorBase<kaldi::BaseFloat>* feat);
+    virtual size_t Dim() const { return dim_; }
+    void ReadFeats(kaldi::Matrix<kaldi::BaseFloat>* feats);
+
+  private: 
+    void Hanning(std::vector<kaldi::BaseFloat>* data) const;
+    bool Compute(const std::vector<kaldi::BaseFloat>& wave,
+                 std::vector<std::vector<kaldi::BaseFloat>>& feat);
+    void Compute(const kaldi::VectorBase<kaldi::BaseFloat>& input,
+                 kaldi::VectorBase<kaldi::BaseFloat>* feature);
+    bool NumpyFft(std::vector<kaldi::BaseFloat>* v,
+                  std::vector<kaldi::BaseFloat>* real,
+                  std::vector<kaldi::BaseFloat>* img) const;
+
+    kaldi::int32 fft_points_;
+    size_t dim_;
+    std::vector<kaldi::BaseFloat> hanning_window_;
+    kaldi::BaseFloat hanning_window_energy_;
+    LinearSpectrogramOptions opts_;
+    kaldi::Vector<kaldi::BaseFloat> waveform_; // remove later, todo(SmileGoat)
+    std::unique_ptr<FeatureExtractorInterface> base_extractor_;
+    DISALLOW_COPY_AND_ASSIGN(LinearSpectrogram);
+};
+
+
+}  // namespace ppspeech

speechx/speechx/frontend/mfcc.h

@@ -0,0 +1,16 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// wrap the mfcc feat of kaldi, todo (SmileGoat)
+#include "kaldi/feat/feature-mfcc.h"

speechx/speechx/frontend/normalizer.cc

@@ -0,0 +1,130 @@
+
+#include "frontend/normalizer.h"
+
+namespace ppspeech {
+
+using kaldi::Vector;
+using kaldi::VectorBase;
+using kaldi::BaseFloat;
+using std::vector;
+
+DecibelNormalizer::DecibelNormalizer(const DecibelNormalizerOptions& opts) {
+  opts_ = opts;
+  dim_ = 0;
+}
+                                    
+void DecibelNormalizer::AcceptWaveform(const kaldi::VectorBase<BaseFloat>& input) {
+  dim_ = input.Dim();
+  waveform_.Resize(input.Dim());
+  waveform_.CopyFromVec(input);
+}
+
+void DecibelNormalizer::Read(kaldi::VectorBase<BaseFloat>* feat) {
+  if (waveform_.Dim() == 0) return;
+  Compute(waveform_, feat);
+}
+
+//todo remove later
+void CopyVector2StdVector(const kaldi::VectorBase<BaseFloat>& input,
+                          vector<BaseFloat>* output) {
+  if (input.Dim() == 0) return;
+  output->resize(input.Dim());
+  for (size_t idx = 0; idx < input.Dim(); ++idx) {
+    (*output)[idx] = input(idx);
+  }
+}
+
+void CopyStdVector2Vector(const vector<BaseFloat>& input,
+                          VectorBase<BaseFloat>* output) {
+  if (input.empty()) return;
+  assert(input.size() == output->Dim());
+  for (size_t idx = 0; idx < input.size(); ++idx) {
+    (*output)(idx) = input[idx];
+  }
+}
+
+bool DecibelNormalizer::Compute(const VectorBase<BaseFloat>& input,
+                                VectorBase<BaseFloat>* feat) const {
+  // calculate db rms
+  BaseFloat rms_db = 0.0;
+  BaseFloat mean_square = 0.0;
+  BaseFloat gain = 0.0;
+  BaseFloat wave_float_normlization = 1.0f / (std::pow(2, 16 - 1));
+
+  vector<BaseFloat> samples;
+  samples.resize(input.Dim());
+  for (int32 i = 0; i < samples.size(); ++i) {
+    samples[i] = input(i);
+  }
+  
+  // square
+  for (auto &d : samples) {
+    if (opts_.convert_int_float) {
+    d = d * wave_float_normlization;
+    }
+    mean_square += d * d;
+  }
+
+  // mean
+  mean_square /= samples.size();
+  rms_db = 10 * std::log10(mean_square);
+  gain = opts_.target_db - rms_db;
+
+  if (gain > opts_.max_gain_db) {
+    LOG(ERROR) << "Unable to normalize segment to " << opts_.target_db << "dB,"
+                << "because the the probable gain have exceeds opts_.max_gain_db" 
+                <<  opts_.max_gain_db << "dB.";
+    return false;
+  }
+
+  // Note that this is an in-place transformation.
+  for (auto &item : samples) {
+    // python item *= 10.0 ** (gain / 20.0)
+    item *= std::pow(10.0, gain / 20.0);
+  }
+  
+  CopyStdVector2Vector(samples, feat);
+  return true;
+}
+
+/*
+PPNormalizer::PPNormalizer(
+    const PPNormalizerOptions& opts,
+    const std::unique_ptr<FeatureExtractorInterface>& pre_extractor) {
+
+}
+                                    
+void PPNormalizer::AcceptWavefrom(const Vector<BaseFloat>& input) {
+
+}
+
+void PPNormalizer::Read(Vector<BaseFloat>* feat) {
+
+}
+
+bool PPNormalizer::Compute(const Vector<BaseFloat>& input,
+                           Vector<BaseFloat>>* feat) {
+   if ((input.Dim() % mean_.Dim()) == 0) {
+        LOG(ERROR) << "CMVN dimension is wrong!";
+        return false;
+   }
+
+    try {
+      int32 size = mean_.Dim();
+      feat->Resize(input.Dim());
+      for (int32 row_idx = 0; row_idx < j; ++row_idx) {
+        int32 base_idx  = row_idx * size;
+        for (int32 idx = 0; idx < mean_.Dim(); ++idx) {
+          (*feat)(base_idx + idx) = (input(base_dix + idx) - mean_(idx))* variance_(idx);
+        }       
+      }
+
+    } catch(const std::exception& e) {
+        std::cerr << e.what() << '\n';
+        return false;
+    }
+
+    return true;
+}*/
+
+} // namespace ppspeech

speechx/speechx/frontend/normalizer.h

@@ -0,0 +1,72 @@
+
+#pragma once
+
+#include "base/common.h"
+#include "frontend/feature_extractor_interface.h"
+#include "kaldi/util/options-itf.h"
+
+namespace ppspeech {
+
+
+struct DecibelNormalizerOptions {
+  float target_db;
+  float max_gain_db;
+  bool convert_int_float;
+  DecibelNormalizerOptions() :
+    target_db(-20),
+    max_gain_db(300.0),
+    convert_int_float(false) {}
+
+    void Register(kaldi::OptionsItf* opts) {
+      opts->Register("target-db", &target_db, "target db for db normalization");
+      opts->Register("max-gain-db", &max_gain_db, "max gain db for db normalization");
+      opts->Register("convert-int-float", &convert_int_float, "if convert int samples to float");
+    }
+};
+
+class DecibelNormalizer : public FeatureExtractorInterface {
+  public:
+    explicit DecibelNormalizer(const DecibelNormalizerOptions& opts);
+    virtual void AcceptWaveform(const kaldi::VectorBase<kaldi::BaseFloat>& input);
+    virtual void Read(kaldi::VectorBase<kaldi::BaseFloat>* feat);
+    virtual size_t Dim() const { return 0; }
+    bool Compute(const kaldi::VectorBase<kaldi::BaseFloat>& input,
+                 kaldi::VectorBase<kaldi::BaseFloat>* feat) const;
+  private:
+    DecibelNormalizerOptions opts_;
+    size_t dim_;
+    std::unique_ptr<FeatureExtractorInterface> base_extractor_;
+    kaldi::Vector<kaldi::BaseFloat> waveform_;
+};
+
+/*
+struct NormalizerOptions {
+  std::string mean_std_path;
+  NormalizerOptions() :
+    mean_std_path("") {}
+
+  void Register(kaldi::OptionsItf* opts) {
+    opts->Register("mean-std", &mean_std_path, "mean std file");
+  }
+};
+
+// todo refactor later (SmileGoat)
+class PPNormalizer : public FeatureExtractorInterface {
+  public:
+    explicit PPNormalizer(const NormalizerOptions& opts, 
+                          const std::unique_ptr<FeatureExtractorInterface>& pre_extractor);
+    ~PPNormalizer() {}
+    virtual void AcceptWavefrom(const kaldi::Vector<kaldi::BaseFloat>& input);
+    virtual void Read(kaldi::Vector<kaldi::BaseFloat>* feat);
+    virtual size_t Dim() const;
+    bool Compute(const kaldi::Vector<kaldi::BaseFloat>& input,
+                 kaldi::Vector<kaldi::BaseFloat>>& feat);
+
+  private:
+    bool _initialized;
+    kaldi::Vector<float> mean_;
+    kaldi::Vector<float> variance_;
+    NormalizerOptions _opts;
+};
+*/
+}  // namespace ppspeech

speechx/speechx/frontend/window.h

@@ -0,0 +1,16 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// extract the window of kaldi feat.
+

speechx/speechx/kaldi/decoder/lattice-faster-decoder.h

@@ -0,0 +1,549 @@
+// decoder/lattice-faster-decoder.h
+
+// Copyright 2009-2013  Microsoft Corporation;  Mirko Hannemann;
+//           2013-2014  Johns Hopkins University (Author: Daniel Povey)
+//                2014  Guoguo Chen
+//                2018  Zhehuai Chen
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef KALDI_DECODER_LATTICE_FASTER_DECODER_H_
+#define KALDI_DECODER_LATTICE_FASTER_DECODER_H_
+
+#include "decoder/grammar-fst.h"
+#include "fst/fstlib.h"
+#include "fst/memory.h"
+#include "fstext/fstext-lib.h"
+#include "itf/decodable-itf.h"
+#include "lat/determinize-lattice-pruned.h"
+#include "lat/kaldi-lattice.h"
+#include "util/hash-list.h"
+#include "util/stl-utils.h"
+
+namespace kaldi {
+
+struct LatticeFasterDecoderConfig {
+  BaseFloat beam;
+  int32 max_active;
+  int32 min_active;
+  BaseFloat lattice_beam;
+  int32 prune_interval;
+  bool determinize_lattice; // not inspected by this class... used in
+                            // command-line program.
+  BaseFloat beam_delta;
+  BaseFloat hash_ratio;
+  // Note: we don't make prune_scale configurable on the command line, it's not
+  // a very important parameter.  It affects the algorithm that prunes the
+  // tokens as we go.
+  BaseFloat prune_scale;
+
+  // Number of elements in the block for Token and ForwardLink memory
+  // pool allocation.
+  int32 memory_pool_tokens_block_size;
+  int32 memory_pool_links_block_size;
+
+  // Most of the options inside det_opts are not actually queried by the
+  // LatticeFasterDecoder class itself, but by the code that calls it, for
+  // example in the function DecodeUtteranceLatticeFaster.
+  fst::DeterminizeLatticePhonePrunedOptions det_opts;
+
+  LatticeFasterDecoderConfig()
+      : beam(16.0),
+        max_active(std::numeric_limits<int32>::max()),
+        min_active(200),
+        lattice_beam(10.0),
+        prune_interval(25),
+        determinize_lattice(true),
+        beam_delta(0.5),
+        hash_ratio(2.0),
+        prune_scale(0.1),
+        memory_pool_tokens_block_size(1 << 8),
+        memory_pool_links_block_size(1 << 8) {}
+  void Register(OptionsItf *opts) {
+    det_opts.Register(opts);
+    opts->Register("beam", &beam, "Decoding beam.  Larger->slower, more accurate.");
+    opts->Register("max-active", &max_active, "Decoder max active states.  Larger->slower; "
+                   "more accurate");
+    opts->Register("min-active", &min_active, "Decoder minimum #active states.");
+    opts->Register("lattice-beam", &lattice_beam, "Lattice generation beam.  Larger->slower, "
+                   "and deeper lattices");
+    opts->Register("prune-interval", &prune_interval, "Interval (in frames) at "
+                   "which to prune tokens");
+    opts->Register("determinize-lattice", &determinize_lattice, "If true, "
+                   "determinize the lattice (lattice-determinization, keeping only "
+                   "best pdf-sequence for each word-sequence).");
+    opts->Register("beam-delta", &beam_delta, "Increment used in decoding-- this "
+                   "parameter is obscure and relates to a speedup in the way the "
+                   "max-active constraint is applied.  Larger is more accurate.");
+    opts->Register("hash-ratio", &hash_ratio, "Setting used in decoder to "
+                   "control hash behavior");
+    opts->Register("memory-pool-tokens-block-size", &memory_pool_tokens_block_size,
+                   "Memory pool block size suggestion for storing tokens (in elements). "
+                   "Smaller uses less memory but increases cache misses.");
+    opts->Register("memory-pool-links-block-size", &memory_pool_links_block_size,
+                   "Memory pool block size suggestion for storing links (in elements). "
+                   "Smaller uses less memory but increases cache misses.");
+  }
+  void Check() const {
+    KALDI_ASSERT(beam > 0.0 && max_active > 1 && lattice_beam > 0.0
+                 && min_active <= max_active
+                 && prune_interval > 0 && beam_delta > 0.0 && hash_ratio >= 1.0
+                 && prune_scale > 0.0 && prune_scale < 1.0);
+  }
+};
+
+namespace decoder {
+// We will template the decoder on the token type as well as the FST type; this
+// is a mechanism so that we can use the same underlying decoder code for
+// versions of the decoder that support quickly getting the best path
+// (LatticeFasterOnlineDecoder, see lattice-faster-online-decoder.h) and also
+// those that do not (LatticeFasterDecoder).
+
+
+// ForwardLinks are the links from a token to a token on the next frame.
+// or sometimes on the current frame (for input-epsilon links).
+template <typename Token>
+struct ForwardLink {
+  using Label = fst::StdArc::Label;
+
+  Token *next_tok;  // the next token [or NULL if represents final-state]
+  Label ilabel;  // ilabel on arc
+  Label olabel;  // olabel on arc
+  BaseFloat graph_cost;  // graph cost of traversing arc (contains LM, etc.)
+  BaseFloat acoustic_cost;  // acoustic cost (pre-scaled) of traversing arc
+  ForwardLink *next;  // next in singly-linked list of forward arcs (arcs
+                      // in the state-level lattice) from a token.
+  inline ForwardLink(Token *next_tok, Label ilabel, Label olabel,
+                     BaseFloat graph_cost, BaseFloat acoustic_cost,
+                     ForwardLink *next):
+      next_tok(next_tok), ilabel(ilabel), olabel(olabel),
+      graph_cost(graph_cost), acoustic_cost(acoustic_cost),
+      next(next) { }
+};
+
+
+struct StdToken {
+  using ForwardLinkT = ForwardLink<StdToken>;
+  using Token = StdToken;
+
+  // Standard token type for LatticeFasterDecoder.  Each active HCLG
+  // (decoding-graph) state on each frame has one token.
+
+  // tot_cost is the total (LM + acoustic) cost from the beginning of the
+  // utterance up to this point.  (but see cost_offset_, which is subtracted
+  // to keep it in a good numerical range).
+  BaseFloat tot_cost;
+
+  // exta_cost is >= 0.  After calling PruneForwardLinks, this equals the
+  // minimum difference between the cost of the best path that this link is a
+  // part of, and the cost of the absolute best path, under the assumption that
+  // any of the currently active states at the decoding front may eventually
+  // succeed (e.g. if you were to take the currently active states one by one
+  // and compute this difference, and then take the minimum).
+  BaseFloat extra_cost;
+
+  // 'links' is the head of singly-linked list of ForwardLinks, which is what we
+  // use for lattice generation.
+  ForwardLinkT *links;
+
+  //'next' is the next in the singly-linked list of tokens for this frame.
+  Token *next;
+
+  // This function does nothing and should be optimized out; it's needed
+  // so we can share the regular LatticeFasterDecoderTpl code and the code
+  // for LatticeFasterOnlineDecoder that supports fast traceback.
+  inline void SetBackpointer (Token *backpointer) { }
+
+  // This constructor just ignores the 'backpointer' argument.  That argument is
+  // needed so that we can use the same decoder code for LatticeFasterDecoderTpl
+  // and LatticeFasterOnlineDecoderTpl (which needs backpointers to support a
+  // fast way to obtain the best path).
+  inline StdToken(BaseFloat tot_cost, BaseFloat extra_cost, ForwardLinkT *links,
+                  Token *next, Token *backpointer):
+      tot_cost(tot_cost), extra_cost(extra_cost), links(links), next(next) { }
+};
+
+struct BackpointerToken {
+  using ForwardLinkT = ForwardLink<BackpointerToken>;
+  using Token = BackpointerToken;
+
+  // BackpointerToken is like Token but also
+  // Standard token type for LatticeFasterDecoder.  Each active HCLG
+  // (decoding-graph) state on each frame has one token.
+
+  // tot_cost is the total (LM + acoustic) cost from the beginning of the
+  // utterance up to this point.  (but see cost_offset_, which is subtracted
+  // to keep it in a good numerical range).
+  BaseFloat tot_cost;
+
+  // exta_cost is >= 0.  After calling PruneForwardLinks, this equals
+  // the minimum difference between the cost of the best path, and the cost of
+  // this is on, and the cost of the absolute best path, under the assumption
+  // that any of the currently active states at the decoding front may
+  // eventually succeed (e.g. if you were to take the currently active states
+  // one by one and compute this difference, and then take the minimum).
+  BaseFloat extra_cost;
+
+  // 'links' is the head of singly-linked list of ForwardLinks, which is what we
+  // use for lattice generation.
+  ForwardLinkT *links;
+
+  //'next' is the next in the singly-linked list of tokens for this frame.
+  BackpointerToken *next;
+
+  // Best preceding BackpointerToken (could be a on this frame, connected to
+  // this via an epsilon transition, or on a previous frame).  This is only
+  // required for an efficient GetBestPath function in
+  // LatticeFasterOnlineDecoderTpl; it plays no part in the lattice generation
+  // (the "links" list is what stores the forward links, for that).
+  Token *backpointer;
+
+  inline void SetBackpointer (Token *backpointer) {
+    this->backpointer = backpointer;
+  }
+
+  inline BackpointerToken(BaseFloat tot_cost, BaseFloat extra_cost, ForwardLinkT *links,
+                          Token *next, Token *backpointer):
+      tot_cost(tot_cost), extra_cost(extra_cost), links(links), next(next),
+      backpointer(backpointer) { }
+};
+
+}  // namespace decoder
+
+
+/** This is the "normal" lattice-generating decoder.
+    See \ref lattices_generation \ref decoders_faster and \ref decoders_simple
+     for more information.
+
+   The decoder is templated on the FST type and the token type.  The token type
+   will normally be StdToken, but also may be BackpointerToken which is to support
+   quick lookup of the current best path (see lattice-faster-online-decoder.h)
+
+   The FST you invoke this decoder which is expected to equal
+   Fst::Fst<fst::StdArc>, a.k.a. StdFst, or GrammarFst.  If you invoke it with
+   FST == StdFst and it notices that the actual FST type is
+   fst::VectorFst<fst::StdArc> or fst::ConstFst<fst::StdArc>, the decoder object
+   will internally cast itself to one that is templated on those more specific
+   types; this is an optimization for speed.
+ */
+template <typename FST, typename Token = decoder::StdToken>
+class LatticeFasterDecoderTpl {
+ public:
+  using Arc = typename FST::Arc;
+  using Label = typename Arc::Label;
+  using StateId = typename Arc::StateId;
+  using Weight = typename Arc::Weight;
+  using ForwardLinkT = decoder::ForwardLink<Token>;
+
+  // Instantiate this class once for each thing you have to decode.
+  // This version of the constructor does not take ownership of
+  // 'fst'.
+  LatticeFasterDecoderTpl(const FST &fst,
+                          const LatticeFasterDecoderConfig &config);
+
+  // This version of the constructor takes ownership of the fst, and will delete
+  // it when this object is destroyed.
+  LatticeFasterDecoderTpl(const LatticeFasterDecoderConfig &config,
+                          FST *fst);
+
+  void SetOptions(const LatticeFasterDecoderConfig &config) {
+    config_ = config;
+  }
+
+  const LatticeFasterDecoderConfig &GetOptions() const {
+    return config_;
+  }
+
+  ~LatticeFasterDecoderTpl();
+
+  /// Decodes until there are no more frames left in the "decodable" object..
+  /// note, this may block waiting for input if the "decodable" object blocks.
+  /// Returns true if any kind of traceback is available (not necessarily from a
+  /// final state).
+  bool Decode(DecodableInterface *decodable);
+
+
+  /// says whether a final-state was active on the last frame.  If it was not, the
+  /// lattice (or traceback) will end with states that are not final-states.
+  bool ReachedFinal() const {
+    return FinalRelativeCost() != std::numeric_limits<BaseFloat>::infinity();
+  }
+
+  /// Outputs an FST corresponding to the single best path through the lattice.
+  /// Returns true if result is nonempty (using the return status is deprecated,
+  /// it will become void).  If "use_final_probs" is true AND we reached the
+  /// final-state of the graph then it will include those as final-probs, else
+  /// it will treat all final-probs as one.  Note: this just calls GetRawLattice()
+  /// and figures out the shortest path.
+  bool GetBestPath(Lattice *ofst,
+                   bool use_final_probs = true) const;
+
+  /// Outputs an FST corresponding to the raw, state-level
+  /// tracebacks.  Returns true if result is nonempty.
+  /// If "use_final_probs" is true AND we reached the final-state
+  /// of the graph then it will include those as final-probs, else
+  /// it will treat all final-probs as one.
+  /// The raw lattice will be topologically sorted.
+  ///
+  /// See also GetRawLatticePruned in lattice-faster-online-decoder.h,
+  /// which also supports a pruning beam, in case for some reason
+  /// you want it pruned tighter than the regular lattice beam.
+  /// We could put that here in future needed.
+  bool GetRawLattice(Lattice *ofst, bool use_final_probs = true) const;
+
+
+
+  /// [Deprecated, users should now use GetRawLattice and determinize it
+  /// themselves, e.g. using DeterminizeLatticePhonePrunedWrapper].
+  /// Outputs an FST corresponding to the lattice-determinized
+  /// lattice (one path per word sequence).   Returns true if result is nonempty.
+  /// If "use_final_probs" is true AND we reached the final-state of the graph
+  /// then it will include those as final-probs, else it will treat all
+  /// final-probs as one.
+  bool GetLattice(CompactLattice *ofst,
+                  bool use_final_probs = true) const;
+
+  /// InitDecoding initializes the decoding, and should only be used if you
+  /// intend to call AdvanceDecoding().  If you call Decode(), you don't need to
+  /// call this.  You can also call InitDecoding if you have already decoded an
+  /// utterance and want to start with a new utterance.
+  void InitDecoding();
+
+  /// This will decode until there are no more frames ready in the decodable
+  /// object.  You can keep calling it each time more frames become available.
+  /// If max_num_frames is specified, it specifies the maximum number of frames
+  /// the function will decode before returning.
+  void AdvanceDecoding(DecodableInterface *decodable,
+                       int32 max_num_frames = -1);
+
+  /// This function may be optionally called after AdvanceDecoding(), when you
+  /// do not plan to decode any further.  It does an extra pruning step that
+  /// will help to prune the lattices output by GetLattice and (particularly)
+  /// GetRawLattice more completely, particularly toward the end of the
+  /// utterance.  If you call this, you cannot call AdvanceDecoding again (it
+  /// will fail), and you cannot call GetLattice() and related functions with
+  /// use_final_probs = false.  Used to be called PruneActiveTokensFinal().
+  void FinalizeDecoding();
+
+  /// FinalRelativeCost() serves the same purpose as ReachedFinal(), but gives
+  /// more information.  It returns the difference between the best (final-cost
+  /// plus cost) of any token on the final frame, and the best cost of any token
+  /// on the final frame.  If it is infinity it means no final-states were
+  /// present on the final frame.  It will usually be nonnegative.  If it not
+  /// too positive (e.g. < 5 is my first guess, but this is not tested) you can
+  /// take it as a good indication that we reached the final-state with
+  /// reasonable likelihood.
+  BaseFloat FinalRelativeCost() const;
+
+
+  // Returns the number of frames decoded so far.  The value returned changes
+  // whenever we call ProcessEmitting().
+  inline int32 NumFramesDecoded() const { return active_toks_.size() - 1; }
+
+ protected:
+  // we make things protected instead of private, as code in
+  // LatticeFasterOnlineDecoderTpl, which inherits from this, also uses the
+  // internals.
+
+  // Deletes the elements of the singly linked list tok->links.
+  void DeleteForwardLinks(Token *tok);
+
+  // head of per-frame list of Tokens (list is in topological order),
+  // and something saying whether we ever pruned it using PruneForwardLinks.
+  struct TokenList {
+    Token *toks;
+    bool must_prune_forward_links;
+    bool must_prune_tokens;
+    TokenList(): toks(NULL), must_prune_forward_links(true),
+                 must_prune_tokens(true) { }
+  };
+
+  using Elem = typename HashList<StateId, Token*>::Elem;
+  // Equivalent to:
+  //  struct Elem {
+  //    StateId key;
+  //    Token *val;
+  //    Elem *tail;
+  //  };
+
+  void PossiblyResizeHash(size_t num_toks);
+
+  // FindOrAddToken either locates a token in hash of toks_, or if necessary
+  // inserts a new, empty token (i.e. with no forward links) for the current
+  // frame.  [note: it's inserted if necessary into hash toks_ and also into the
+  // singly linked list of tokens active on this frame (whose head is at
+  // active_toks_[frame]).  The frame_plus_one argument is the acoustic frame
+  // index plus one, which is used to index into the active_toks_ array.
+  // Returns the Token pointer.  Sets "changed" (if non-NULL) to true if the
+  // token was newly created or the cost changed.
+  // If Token == StdToken, the 'backpointer' argument has no purpose (and will
+  // hopefully be optimized out).
+  inline Elem *FindOrAddToken(StateId state, int32 frame_plus_one,
+                              BaseFloat tot_cost, Token *backpointer,
+                              bool *changed);
+
+  // prunes outgoing links for all tokens in active_toks_[frame]
+  // it's called by PruneActiveTokens
+  // all links, that have link_extra_cost > lattice_beam are pruned
+  // delta is the amount by which the extra_costs must change
+  // before we set *extra_costs_changed = true.
+  // If delta is larger,  we'll tend to go back less far
+  //    toward the beginning of the file.
+  // extra_costs_changed is set to true if extra_cost was changed for any token
+  // links_pruned is set to true if any link in any token was pruned
+  void PruneForwardLinks(int32 frame_plus_one, bool *extra_costs_changed,
+                         bool *links_pruned,
+                         BaseFloat delta);
+
+  // This function computes the final-costs for tokens active on the final
+  // frame.  It outputs to final-costs, if non-NULL, a map from the Token*
+  // pointer to the final-prob of the corresponding state, for all Tokens
+  // that correspond to states that have final-probs.  This map will be
+  // empty if there were no final-probs.  It outputs to
+  // final_relative_cost, if non-NULL, the difference between the best
+  // forward-cost including the final-prob cost, and the best forward-cost
+  // without including the final-prob cost (this will usually be positive), or
+  // infinity if there were no final-probs.  [c.f. FinalRelativeCost(), which
+  // outputs this quanitity].  It outputs to final_best_cost, if
+  // non-NULL, the lowest for any token t active on the final frame, of
+  // forward-cost[t] + final-cost[t], where final-cost[t] is the final-cost in
+  // the graph of the state corresponding to token t, or the best of
+  // forward-cost[t] if there were no final-probs active on the final frame.
+  // You cannot call this after FinalizeDecoding() has been called; in that
+  // case you should get the answer from class-member variables.
+  void ComputeFinalCosts(unordered_map<Token*, BaseFloat> *final_costs,
+                         BaseFloat *final_relative_cost,
+                         BaseFloat *final_best_cost) const;
+
+  // PruneForwardLinksFinal is a version of PruneForwardLinks that we call
+  // on the final frame.  If there are final tokens active, it uses
+  // the final-probs for pruning, otherwise it treats all tokens as final.
+  void PruneForwardLinksFinal();
+
+  // Prune away any tokens on this frame that have no forward links.
+  // [we don't do this in PruneForwardLinks because it would give us
+  // a problem with dangling pointers].
+  // It's called by PruneActiveTokens if any forward links have been pruned
+  void PruneTokensForFrame(int32 frame_plus_one);
+
+
+  // Go backwards through still-alive tokens, pruning them if the
+  // forward+backward cost is more than lat_beam away from the best path.  It's
+  // possible to prove that this is "correct" in the sense that we won't lose
+  // anything outside of lat_beam, regardless of what happens in the future.
+  // delta controls when it considers a cost to have changed enough to continue
+  // going backward and propagating the change.  larger delta -> will recurse
+  // less far.
+  void PruneActiveTokens(BaseFloat delta);
+
+  /// Gets the weight cutoff.  Also counts the active tokens.
+  BaseFloat GetCutoff(Elem *list_head, size_t *tok_count,
+                      BaseFloat *adaptive_beam, Elem **best_elem);
+
+  /// Processes emitting arcs for one frame.  Propagates from prev_toks_ to
+  /// cur_toks_.  Returns the cost cutoff for subsequent ProcessNonemitting() to
+  /// use.
+  BaseFloat ProcessEmitting(DecodableInterface *decodable);
+
+  /// Processes nonemitting (epsilon) arcs for one frame.  Called after
+  /// ProcessEmitting() on each frame.  The cost cutoff is computed by the
+  /// preceding ProcessEmitting().
+  void ProcessNonemitting(BaseFloat cost_cutoff);
+
+  // HashList defined in ../util/hash-list.h.  It actually allows us to maintain
+  // more than one list (e.g. for current and previous frames), but only one of
+  // them at a time can be indexed by StateId.  It is indexed by frame-index
+  // plus one, where the frame-index is zero-based, as used in decodable object.
+  // That is, the emitting probs of frame t are accounted for in tokens at
+  // toks_[t+1].  The zeroth frame is for nonemitting transition at the start of
+  // the graph.
+  HashList<StateId, Token*> toks_;
+
+  std::vector<TokenList> active_toks_; // Lists of tokens, indexed by
+  // frame (members of TokenList are toks, must_prune_forward_links,
+  // must_prune_tokens).
+  std::vector<const Elem* > queue_;  // temp variable used in ProcessNonemitting,
+  std::vector<BaseFloat> tmp_array_;  // used in GetCutoff.
+
+  // fst_ is a pointer to the FST we are decoding from.
+  const FST *fst_;
+  // delete_fst_ is true if the pointer fst_ needs to be deleted when this
+  // object is destroyed.
+  bool delete_fst_;
+
+  std::vector<BaseFloat> cost_offsets_; // This contains, for each
+  // frame, an offset that was added to the acoustic log-likelihoods on that
+  // frame in order to keep everything in a nice dynamic range i.e.  close to
+  // zero, to reduce roundoff errors.
+  LatticeFasterDecoderConfig config_;
+  int32 num_toks_; // current total #toks allocated...
+  bool warned_;
+
+  /// decoding_finalized_ is true if someone called FinalizeDecoding().  [note,
+  /// calling this is optional].  If true, it's forbidden to decode more.  Also,
+  /// if this is set, then the output of ComputeFinalCosts() is in the next
+  /// three variables.  The reason we need to do this is that after
+  /// FinalizeDecoding() calls PruneTokensForFrame() for the final frame, some
+  /// of the tokens on the last frame are freed, so we free the list from toks_
+  /// to avoid having dangling pointers hanging around.
+  bool decoding_finalized_;
+  /// For the meaning of the next 3 variables, see the comment for
+  /// decoding_finalized_ above., and ComputeFinalCosts().
+  unordered_map<Token*, BaseFloat> final_costs_;
+  BaseFloat final_relative_cost_;
+  BaseFloat final_best_cost_;
+
+  // Memory pools for storing tokens and forward links.
+  // We use it to decrease the work put on allocator and to move some of data
+  // together. Too small block sizes will result in more work to allocator but
+  // bigger ones increase the memory usage.
+  fst::MemoryPool<Token> token_pool_;
+  fst::MemoryPool<ForwardLinkT> forward_link_pool_;
+
+  // There are various cleanup tasks... the toks_ structure contains
+  // singly linked lists of Token pointers, where Elem is the list type.
+  // It also indexes them in a hash, indexed by state (this hash is only
+  // maintained for the most recent frame).  toks_.Clear()
+  // deletes them from the hash and returns the list of Elems.  The
+  // function DeleteElems calls toks_.Delete(elem) for each elem in
+  // the list, which returns ownership of the Elem to the toks_ structure
+  // for reuse, but does not delete the Token pointer.  The Token pointers
+  // are reference-counted and are ultimately deleted in PruneTokensForFrame,
+  // but are also linked together on each frame by their own linked-list,
+  // using the "next" pointer.  We delete them manually.
+  void DeleteElems(Elem *list);
+
+  // This function takes a singly linked list of tokens for a single frame, and
+  // outputs a list of them in topological order (it will crash if no such order
+  // can be found, which will typically be due to decoding graphs with epsilon
+  // cycles, which are not allowed).  Note: the output list may contain NULLs,
+  // which the caller should pass over; it just happens to be more efficient for
+  // the algorithm to output a list that contains NULLs.
+  static void TopSortTokens(Token *tok_list,
+                            std::vector<Token*> *topsorted_list);
+
+  void ClearActiveTokens();
+
+  KALDI_DISALLOW_COPY_AND_ASSIGN(LatticeFasterDecoderTpl);
+};
+
+typedef LatticeFasterDecoderTpl<fst::StdFst, decoder::StdToken> LatticeFasterDecoder;
+
+
+
+} // end namespace kaldi.
+
+#endif

speechx/speechx/kaldi/decoder/lattice-faster-online-decoder.cc

@@ -0,0 +1,285 @@
+// decoder/lattice-faster-online-decoder.cc
+
+// Copyright 2009-2012  Microsoft Corporation  Mirko Hannemann
+//           2013-2014  Johns Hopkins University (Author: Daniel Povey)
+//                2014  Guoguo Chen
+//                2014  IMSL, PKU-HKUST (author: Wei Shi)
+//                2018  Zhehuai Chen
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+// see note at the top of lattice-faster-decoder.cc, about how to maintain this
+// file in sync with lattice-faster-decoder.cc
+
+#include "decoder/lattice-faster-online-decoder.h"
+#include "lat/lattice-functions.h"
+
+namespace kaldi {
+
+template <typename FST>
+bool LatticeFasterOnlineDecoderTpl<FST>::TestGetBestPath(
+    bool use_final_probs) const {
+  Lattice lat1;
+  {
+    Lattice raw_lat;
+    this->GetRawLattice(&raw_lat, use_final_probs);
+    ShortestPath(raw_lat, &lat1);
+  }
+  Lattice lat2;
+  GetBestPath(&lat2, use_final_probs);
+  BaseFloat delta = 0.1;
+  int32 num_paths = 1;
+  if (!fst::RandEquivalent(lat1, lat2, num_paths, delta, rand())) {
+    KALDI_WARN << "Best-path test failed";
+    return false;
+  } else {
+    return true;
+  }
+}
+
+
+// Outputs an FST corresponding to the single best path through the lattice.
+template <typename FST>
+bool LatticeFasterOnlineDecoderTpl<FST>::GetBestPath(Lattice *olat,
+                                                     bool use_final_probs) const {
+  olat->DeleteStates();
+  BaseFloat final_graph_cost;
+  BestPathIterator iter = BestPathEnd(use_final_probs, &final_graph_cost);
+  if (iter.Done())
+    return false;  // would have printed warning.
+  StateId state = olat->AddState();
+  olat->SetFinal(state, LatticeWeight(final_graph_cost, 0.0));
+  while (!iter.Done()) {
+    LatticeArc arc;
+    iter = TraceBackBestPath(iter, &arc);
+    arc.nextstate = state;
+    StateId new_state = olat->AddState();
+    olat->AddArc(new_state, arc);
+    state = new_state;
+  }
+  olat->SetStart(state);
+  return true;
+}
+
+template <typename FST>
+typename LatticeFasterOnlineDecoderTpl<FST>::BestPathIterator LatticeFasterOnlineDecoderTpl<FST>::BestPathEnd(
+    bool use_final_probs,
+    BaseFloat *final_cost_out) const {
+  if (this->decoding_finalized_ && !use_final_probs)
+    KALDI_ERR << "You cannot call FinalizeDecoding() and then call "
+              << "BestPathEnd() with use_final_probs == false";
+  KALDI_ASSERT(this->NumFramesDecoded() > 0 &&
+               "You cannot call BestPathEnd if no frames were decoded.");
+
+  unordered_map<Token*, BaseFloat> final_costs_local;
+
+  const unordered_map<Token*, BaseFloat> &final_costs =
+      (this->decoding_finalized_ ? this->final_costs_ :final_costs_local);
+  if (!this->decoding_finalized_ && use_final_probs)
+    this->ComputeFinalCosts(&final_costs_local, NULL, NULL);
+
+  // Singly linked list of tokens on last frame (access list through "next"
+  // pointer).
+  BaseFloat best_cost = std::numeric_limits<BaseFloat>::infinity();
+  BaseFloat best_final_cost = 0;
+  Token *best_tok = NULL;
+  for (Token *tok = this->active_toks_.back().toks;
+       tok != NULL; tok = tok->next) {
+    BaseFloat cost = tok->tot_cost, final_cost = 0.0;
+    if (use_final_probs && !final_costs.empty()) {
+      // if we are instructed to use final-probs, and any final tokens were
+      // active on final frame, include the final-prob in the cost of the token.
+      typename unordered_map<Token*, BaseFloat>::const_iterator
+          iter = final_costs.find(tok);
+      if (iter != final_costs.end()) {
+        final_cost = iter->second;
+        cost += final_cost;
+      } else {
+        cost = std::numeric_limits<BaseFloat>::infinity();
+      }
+    }
+    if (cost < best_cost) {
+      best_cost = cost;
+      best_tok = tok;
+      best_final_cost = final_cost;
+    }
+  }
+  if (best_tok == NULL) {  // this should not happen, and is likely a code error or
+    // caused by infinities in likelihoods, but I'm not making
+    // it a fatal error for now.
+    KALDI_WARN << "No final token found.";
+  }
+  if (final_cost_out)
+    *final_cost_out = best_final_cost;
+  return BestPathIterator(best_tok, this->NumFramesDecoded() - 1);
+}
+
+
+template <typename FST>
+typename LatticeFasterOnlineDecoderTpl<FST>::BestPathIterator LatticeFasterOnlineDecoderTpl<FST>::TraceBackBestPath(
+    BestPathIterator iter, LatticeArc *oarc) const {
+  KALDI_ASSERT(!iter.Done() && oarc != NULL);
+  Token *tok = static_cast<Token*>(iter.tok);
+  int32 cur_t = iter.frame, step_t = 0;
+  if (tok->backpointer != NULL) {
+    // retrieve the correct forward link(with the best link cost)
+    BaseFloat best_cost = std::numeric_limits<BaseFloat>::infinity();
+    ForwardLinkT *link;
+    for (link = tok->backpointer->links;
+         link != NULL; link = link->next) {
+      if (link->next_tok == tok) { // this is a link to "tok"
+        BaseFloat graph_cost = link->graph_cost, 
+                  acoustic_cost = link->acoustic_cost;
+        BaseFloat cost = graph_cost + acoustic_cost;
+        if (cost < best_cost) {
+          oarc->ilabel = link->ilabel;
+          oarc->olabel = link->olabel;
+          if (link->ilabel != 0) {
+            KALDI_ASSERT(static_cast<size_t>(cur_t) < this->cost_offsets_.size());
+            acoustic_cost -= this->cost_offsets_[cur_t];
+            step_t = -1;
+          } else {
+            step_t = 0;
+          }
+          oarc->weight = LatticeWeight(graph_cost, acoustic_cost);
+          best_cost = cost;
+        }
+      }
+    }
+    if (link == NULL &&
+        best_cost == std::numeric_limits<BaseFloat>::infinity()) { // Did not find correct link.
+      KALDI_ERR << "Error tracing best-path back (likely "
+                << "bug in token-pruning algorithm)";
+    }
+  } else {
+    oarc->ilabel = 0;
+    oarc->olabel = 0;
+    oarc->weight = LatticeWeight::One(); // zero costs.
+  }
+  return BestPathIterator(tok->backpointer, cur_t + step_t);
+}
+
+template <typename FST>
+bool LatticeFasterOnlineDecoderTpl<FST>::GetRawLatticePruned(
+    Lattice *ofst,
+    bool use_final_probs,
+    BaseFloat beam) const {
+  typedef LatticeArc Arc;
+  typedef Arc::StateId StateId;
+  typedef Arc::Weight Weight;
+  typedef Arc::Label Label;
+
+  // Note: you can't use the old interface (Decode()) if you want to
+  // get the lattice with use_final_probs = false.  You'd have to do
+  // InitDecoding() and then AdvanceDecoding().
+  if (this->decoding_finalized_ && !use_final_probs)
+    KALDI_ERR << "You cannot call FinalizeDecoding() and then call "
+              << "GetRawLattice() with use_final_probs == false";
+
+  unordered_map<Token*, BaseFloat> final_costs_local;
+
+  const unordered_map<Token*, BaseFloat> &final_costs =
+      (this->decoding_finalized_ ? this->final_costs_ : final_costs_local);
+  if (!this->decoding_finalized_ && use_final_probs)
+    this->ComputeFinalCosts(&final_costs_local, NULL, NULL);
+
+  ofst->DeleteStates();
+  // num-frames plus one (since frames are one-based, and we have
+  // an extra frame for the start-state).
+  int32 num_frames = this->active_toks_.size() - 1;
+  KALDI_ASSERT(num_frames > 0);
+  for (int32 f = 0; f <= num_frames; f++) {
+    if (this->active_toks_[f].toks == NULL) {
+      KALDI_WARN << "No tokens active on frame " << f
+                 << ": not producing lattice.\n";
+      return false;
+    }
+  }
+  unordered_map<Token*, StateId> tok_map;
+  std::queue<std::pair<Token*, int32> > tok_queue;
+  // First initialize the queue and states.  Put the initial state on the queue;
+  // this is the last token in the list active_toks_[0].toks.
+  for (Token *tok = this->active_toks_[0].toks;
+       tok != NULL; tok = tok->next) {
+    if (tok->next == NULL) {
+      tok_map[tok] = ofst->AddState();
+      ofst->SetStart(tok_map[tok]);
+      std::pair<Token*, int32> tok_pair(tok, 0);  // #frame = 0
+      tok_queue.push(tok_pair);
+    }
+  }
+
+  // Next create states for "good" tokens
+  while (!tok_queue.empty()) {
+    std::pair<Token*, int32> cur_tok_pair = tok_queue.front();
+    tok_queue.pop();
+    Token *cur_tok = cur_tok_pair.first;
+    int32 cur_frame = cur_tok_pair.second;
+    KALDI_ASSERT(cur_frame >= 0 &&
+                 cur_frame <= this->cost_offsets_.size());
+
+    typename unordered_map<Token*, StateId>::const_iterator iter =
+        tok_map.find(cur_tok);
+    KALDI_ASSERT(iter != tok_map.end());
+    StateId cur_state = iter->second;
+
+    for (ForwardLinkT *l = cur_tok->links;
+         l != NULL;
+         l = l->next) {
+      Token *next_tok = l->next_tok;
+      if (next_tok->extra_cost < beam) {
+        // so both the current and the next token are good; create the arc
+        int32 next_frame = l->ilabel == 0 ? cur_frame : cur_frame + 1;
+        StateId nextstate;
+        if (tok_map.find(next_tok) == tok_map.end()) {
+          nextstate = tok_map[next_tok] = ofst->AddState();
+          tok_queue.push(std::pair<Token*, int32>(next_tok, next_frame));
+        } else {
+          nextstate = tok_map[next_tok];
+        }
+        BaseFloat cost_offset = (l->ilabel != 0 ?
+                                 this->cost_offsets_[cur_frame] : 0);
+        Arc arc(l->ilabel, l->olabel,
+                Weight(l->graph_cost, l->acoustic_cost - cost_offset),
+                nextstate);
+        ofst->AddArc(cur_state, arc);
+      }
+    }
+    if (cur_frame == num_frames) {
+      if (use_final_probs && !final_costs.empty()) {
+        typename unordered_map<Token*, BaseFloat>::const_iterator iter =
+            final_costs.find(cur_tok);
+        if (iter != final_costs.end())
+          ofst->SetFinal(cur_state, LatticeWeight(iter->second, 0));
+      } else {
+        ofst->SetFinal(cur_state, LatticeWeight::One());
+      }
+    }
+  }
+  return (ofst->NumStates() != 0);
+}
+
+
+
+// Instantiate the template for the FST types that we'll need.
+template class LatticeFasterOnlineDecoderTpl<fst::Fst<fst::StdArc> >;
+template class LatticeFasterOnlineDecoderTpl<fst::VectorFst<fst::StdArc> >;
+template class LatticeFasterOnlineDecoderTpl<fst::ConstFst<fst::StdArc> >;
+template class LatticeFasterOnlineDecoderTpl<fst::ConstGrammarFst >;
+template class LatticeFasterOnlineDecoderTpl<fst::VectorGrammarFst >;
+
+
+} // end namespace kaldi.

speechx/speechx/kaldi/decoder/lattice-faster-online-decoder.h

@@ -0,0 +1,147 @@
+// decoder/lattice-faster-online-decoder.h
+
+// Copyright 2009-2013  Microsoft Corporation;  Mirko Hannemann;
+//           2013-2014  Johns Hopkins University (Author: Daniel Povey)
+//                2014  Guoguo Chen
+//                2018  Zhehuai Chen
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+// see note at the top of lattice-faster-decoder.h, about how to maintain this
+// file in sync with lattice-faster-decoder.h
+
+
+#ifndef KALDI_DECODER_LATTICE_FASTER_ONLINE_DECODER_H_
+#define KALDI_DECODER_LATTICE_FASTER_ONLINE_DECODER_H_
+
+#include "util/stl-utils.h"
+#include "util/hash-list.h"
+#include "fst/fstlib.h"
+#include "itf/decodable-itf.h"
+#include "fstext/fstext-lib.h"
+#include "lat/determinize-lattice-pruned.h"
+#include "lat/kaldi-lattice.h"
+#include "decoder/lattice-faster-decoder.h"
+
+namespace kaldi {
+
+
+
+/** LatticeFasterOnlineDecoderTpl is as LatticeFasterDecoderTpl but also
+    supports an efficient way to get the best path (see the function
+    BestPathEnd()), which is useful in endpointing and in situations where you
+    might want to frequently access the best path.
+
+    This is only templated on the FST type, since the Token type is required to
+    be BackpointerToken.  Actually it only makes sense to instantiate
+    LatticeFasterDecoderTpl with Token == BackpointerToken if you do so indirectly via
+    this child class.
+ */
+template <typename FST>
+class LatticeFasterOnlineDecoderTpl:
+      public LatticeFasterDecoderTpl<FST, decoder::BackpointerToken> {
+ public:
+  using Arc = typename FST::Arc;
+  using Label = typename Arc::Label;
+  using StateId = typename Arc::StateId;
+  using Weight = typename Arc::Weight;
+  using Token = decoder::BackpointerToken;
+  using ForwardLinkT = decoder::ForwardLink<Token>;
+
+  // Instantiate this class once for each thing you have to decode.
+  // This version of the constructor does not take ownership of
+  // 'fst'.
+  LatticeFasterOnlineDecoderTpl(const FST &fst,
+                                const LatticeFasterDecoderConfig &config):
+      LatticeFasterDecoderTpl<FST, Token>(fst, config) { }
+
+  // This version of the initializer takes ownership of 'fst', and will delete
+  // it when this object is destroyed.
+  LatticeFasterOnlineDecoderTpl(const LatticeFasterDecoderConfig &config,
+                                FST *fst):
+      LatticeFasterDecoderTpl<FST, Token>(config, fst) { }
+
+
+  struct BestPathIterator {
+    void *tok;
+    int32 frame;
+    // note, "frame" is the frame-index of the frame you'll get the
+    // transition-id for next time, if you call TraceBackBestPath on this
+    // iterator (assuming it's not an epsilon transition).  Note that this
+    // is one less than you might reasonably expect, e.g. it's -1 for
+    // the nonemitting transitions before the first frame.
+    BestPathIterator(void *t, int32 f): tok(t), frame(f) { }
+    bool Done() const { return tok == NULL; }
+  };
+
+
+  /// Outputs an FST corresponding to the single best path through the lattice.
+  /// This is quite efficient because it doesn't get the entire raw lattice and find
+  /// the best path through it; instead, it uses the BestPathEnd and BestPathIterator
+  /// so it basically traces it back through the lattice.
+  /// Returns true if result is nonempty (using the return status is deprecated,
+  /// it will become void).  If "use_final_probs" is true AND we reached the
+  /// final-state of the graph then it will include those as final-probs, else
+  /// it will treat all final-probs as one.
+  bool GetBestPath(Lattice *ofst,
+                   bool use_final_probs = true) const;
+
+
+  /// This function does a self-test of GetBestPath().  Returns true on
+  /// success; returns false and prints a warning on failure.
+  bool TestGetBestPath(bool use_final_probs = true) const;
+
+
+  /// This function returns an iterator that can be used to trace back
+  /// the best path.  If use_final_probs == true and at least one final state
+  /// survived till the end, it will use the final-probs in working out the best
+  /// final Token, and will output the final cost to *final_cost (if non-NULL),
+  /// else it will use only the forward likelihood, and will put zero in
+  /// *final_cost (if non-NULL).
+  /// Requires that NumFramesDecoded() > 0.
+  BestPathIterator BestPathEnd(bool use_final_probs,
+                               BaseFloat *final_cost = NULL) const;
+
+
+  /// This function can be used in conjunction with BestPathEnd() to trace back
+  /// the best path one link at a time (e.g. this can be useful in endpoint
+  /// detection).  By "link" we mean a link in the graph; not all links cross
+  /// frame boundaries, but each time you see a nonzero ilabel you can interpret
+  /// that as a frame.  The return value is the updated iterator.  It outputs
+  /// the ilabel and olabel, and the (graph and acoustic) weight to the "arc" pointer,
+  /// while leaving its "nextstate" variable unchanged.
+  BestPathIterator TraceBackBestPath(
+      BestPathIterator iter, LatticeArc *arc) const;
+
+
+  /// Behaves the same as GetRawLattice but only processes tokens whose
+  /// extra_cost is smaller than the best-cost plus the specified beam.
+  /// It is only worthwhile to call this function if beam is less than
+  /// the lattice_beam specified in the config; otherwise, it would
+  /// return essentially the same thing as GetRawLattice, but more slowly.
+  bool GetRawLatticePruned(Lattice *ofst,
+                           bool use_final_probs,
+                           BaseFloat beam) const;
+
+  KALDI_DISALLOW_COPY_AND_ASSIGN(LatticeFasterOnlineDecoderTpl);
+};
+
+typedef LatticeFasterOnlineDecoderTpl<fst::StdFst> LatticeFasterOnlineDecoder;
+
+
+} // end namespace kaldi.
+
+#endif

speechx/speechx/kaldi/lat/determinize-lattice-pruned-test.cc

@@ -0,0 +1,147 @@
+// lat/determinize-lattice-pruned-test.cc
+
+// Copyright 2009-2012  Microsoft Corporation
+//           2012-2013  Johns Hopkins University (Author: Daniel Povey)
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+#include "lat/determinize-lattice-pruned.h"
+#include "fstext/lattice-utils.h"
+#include "fstext/fst-test-utils.h"
+#include "lat/kaldi-lattice.h"
+#include "lat/lattice-functions.h"
+
+namespace fst {
+// Caution: these tests are not as generic as you might think from all the
+// templates in the code.  They are basically only valid for LatticeArc.
+// This is partly due to the fact that certain templates need to be instantiated
+// in other .cc files in this directory.
+
+// test that determinization proceeds correctly on general
+// FSTs (not guaranteed determinzable, but we use the
+// max-states option to stop it getting out of control).
+template<class Arc> void TestDeterminizeLatticePruned() {
+  typedef kaldi::int32 Int;
+  typedef typename Arc::Weight Weight;
+  typedef ArcTpl<CompactLatticeWeightTpl<Weight, Int> > CompactArc;
+
+  for(int i = 0; i < 100; i++) {
+    RandFstOptions opts;
+    opts.n_states = 4;
+    opts.n_arcs = 10;
+    opts.n_final = 2;
+    opts.allow_empty = false;
+    opts.weight_multiplier = 0.5; // impt for the randomly generated weights
+    opts.acyclic = true;
+    // to be exactly representable in float,
+    // or this test fails because numerical differences can cause symmetry in
+    // weights to be broken, which causes the wrong path to be chosen as far
+    // as the string part is concerned.
+
+    VectorFst<Arc> *fst = RandPairFst<Arc>(opts);
+
+    bool sorted = TopSort(fst);
+    KALDI_ASSERT(sorted);
+
+    ILabelCompare<Arc> ilabel_comp;
+    if (kaldi::Rand() % 2 == 0)
+      ArcSort(fst, ilabel_comp);
+
+    std::cout << "FST before lattice-determinizing is:\n";
+    {
+      FstPrinter<Arc> fstprinter(*fst, NULL, NULL, NULL, false, true, "\t");
+      fstprinter.Print(&std::cout, "standard output");
+    }
+    VectorFst<Arc> det_fst;
+    try {
+      DeterminizeLatticePrunedOptions lat_opts;
+      lat_opts.max_mem = ((kaldi::Rand() % 2 == 0) ? 100 : 1000);
+      lat_opts.max_states = ((kaldi::Rand() % 2 == 0) ? -1 : 20);
+      lat_opts.max_arcs = ((kaldi::Rand() % 2 == 0) ? -1 : 30);
+      bool ans = DeterminizeLatticePruned<Weight>(*fst, 10.0, &det_fst, lat_opts);
+
+      std::cout << "FST after lattice-determinizing is:\n";
+      {
+        FstPrinter<Arc> fstprinter(det_fst, NULL, NULL, NULL, false, true, "\t");
+        fstprinter.Print(&std::cout, "standard output");
+      }
+      KALDI_ASSERT(det_fst.Properties(kIDeterministic, true) & kIDeterministic);
+      // OK, now determinize it a different way and check equivalence.
+      // [note: it's not normal determinization, it's taking the best path
+      // for any input-symbol sequence....
+
+
+      VectorFst<Arc> pruned_fst(*fst);
+      if (pruned_fst.NumStates() != 0)
+        kaldi::PruneLattice(10.0, &pruned_fst);
+
+      VectorFst<CompactArc> compact_pruned_fst, compact_pruned_det_fst;
+      ConvertLattice<Weight, Int>(pruned_fst, &compact_pruned_fst, false);
+      std::cout << "Compact pruned FST is:\n";
+      {
+        FstPrinter<CompactArc> fstprinter(compact_pruned_fst, NULL, NULL, NULL, false, true, "\t");
+        fstprinter.Print(&std::cout, "standard output");
+      }
+      ConvertLattice<Weight, Int>(det_fst, &compact_pruned_det_fst, false);
+
+      std::cout << "Compact version of determinized FST is:\n";
+      {
+        FstPrinter<CompactArc> fstprinter(compact_pruned_det_fst, NULL, NULL, NULL, false, true, "\t");
+        fstprinter.Print(&std::cout, "standard output");
+      }
+
+      if (ans)
+        KALDI_ASSERT(RandEquivalent(compact_pruned_det_fst, compact_pruned_fst, 5/*paths*/, 0.01/*delta*/, kaldi::Rand()/*seed*/, 100/*path length, max*/));
+    } catch (...) {
+      std::cout << "Failed to lattice-determinize this FST (probably not determinizable)\n";
+    }
+    delete fst;
+  }
+}
+
+// test that determinization proceeds without crash on acyclic FSTs
+// (guaranteed determinizable in this sense).
+template<class Arc> void TestDeterminizeLatticePruned2() {
+  typedef typename Arc::Weight Weight;
+  RandFstOptions opts;
+  opts.acyclic = true;
+  for(int i = 0; i < 100; i++) {
+    VectorFst<Arc> *fst = RandPairFst<Arc>(opts);
+    std::cout << "FST before lattice-determinizing is:\n";
+    {
+      FstPrinter<Arc> fstprinter(*fst, NULL, NULL, NULL, false, true, "\t");
+      fstprinter.Print(&std::cout, "standard output");
+    }
+    VectorFst<Arc> ofst;
+    DeterminizeLatticePruned<Weight>(*fst, 10.0, &ofst);
+    std::cout << "FST after lattice-determinizing is:\n";
+    {
+      FstPrinter<Arc> fstprinter(ofst, NULL, NULL, NULL, false, true, "\t");
+      fstprinter.Print(&std::cout, "standard output");
+    }
+    delete fst;
+  }
+}
+
+
+} // end namespace fst
+
+int main() {
+  using namespace fst;
+  TestDeterminizeLatticePruned<kaldi::LatticeArc>();
+  TestDeterminizeLatticePruned2<kaldi::LatticeArc>();
+  std::cout << "Tests succeeded\n";
+}

speechx/speechx/kaldi/lat/determinize-lattice-pruned.h

@@ -0,0 +1,296 @@
+// lat/determinize-lattice-pruned.h
+
+// Copyright 2009-2012  Microsoft Corporation
+//           2012-2013  Johns Hopkins University (Author: Daniel Povey)
+//                2014  Guoguo Chen
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef KALDI_LAT_DETERMINIZE_LATTICE_PRUNED_H_
+#define KALDI_LAT_DETERMINIZE_LATTICE_PRUNED_H_
+#include <fst/fstlib.h>
+#include <fst/fst-decl.h>
+#include <algorithm>
+#include <map>
+#include <set>
+#include <vector>
+#include "fstext/lattice-weight.h"
+#include "itf/transition-information.h"
+#include "itf/options-itf.h"
+#include "lat/kaldi-lattice.h"
+
+namespace fst {
+
+/// \addtogroup fst_extensions
+///  @{
+
+
+// For example of usage, see test-determinize-lattice-pruned.cc
+
+/*
+   DeterminizeLatticePruned implements a special form of determinization with
+   epsilon removal, optimized for a phase of lattice generation.  This algorithm
+   also does pruning at the same time-- the combination is more efficient as it
+   somtimes prevents us from creating a lot of states that would later be pruned
+   away.  This allows us to increase the lattice-beam and not have the algorithm
+   blow up.  Also, because our algorithm processes states in order from those
+   that appear on high-scoring paths down to those that appear on low-scoring
+   paths, we can easily terminate the algorithm after a certain specified number
+   of states or arcs.
+
+   The input is an FST with weight-type BaseWeightType (usually a pair of floats,
+   with a lexicographical type of order, such as LatticeWeightTpl<float>).
+   Typically this would be a state-level lattice, with input symbols equal to
+   words, and output-symbols equal to p.d.f's (so like the inverse of HCLG).  Imagine representing this as an
+   acceptor of type CompactLatticeWeightTpl<float>, in which the input/output
+   symbols are words, and the weights contain the original weights together with
+   strings (with zero or one symbol in them) containing the original output labels
+   (the p.d.f.'s).  We determinize this using acceptor determinization with
+   epsilon removal.  Remember (from lattice-weight.h) that
+   CompactLatticeWeightTpl has a special kind of semiring where we always take
+   the string corresponding to the best cost (of type BaseWeightType), and
+   discard the other.  This corresponds to taking the best output-label sequence
+   (of p.d.f.'s) for each input-label sequence (of words).  We couldn't use the
+   Gallic weight for this, or it would die as soon as it detected that the input
+   FST was non-functional.  In our case, any acyclic FST (and many cyclic ones)
+   can be determinized.
+   We assume that there is a function
+      Compare(const BaseWeightType &a, const BaseWeightType &b)
+   that returns (-1, 0, 1) according to whether (a < b, a == b, a > b) in the
+   total order on the BaseWeightType... this information should be the
+   same as NaturalLess would give, but it's more efficient to do it this way.
+   You can define this for things like TropicalWeight if you need to instantiate
+   this class for that weight type.
+
+   We implement this determinization in a special way to make it efficient for
+   the types of FSTs that we will apply it to.  One issue is that if we
+   explicitly represent the strings (in CompactLatticeWeightTpl) as vectors of
+   type vector<IntType>, the algorithm takes time quadratic in the length of
+   words (in states), because propagating each arc involves copying a whole
+   vector (of integers representing p.d.f.'s).  Instead we use a hash structure
+   where each string is a pointer (Entry*), and uses a hash from (Entry*,
+   IntType), to the successor string (and a way to get the latest IntType and the
+   ancestor Entry*).  [this is the class LatticeStringRepository].
+
+   Another issue is that rather than representing a determinized-state as a
+   collection of (state, weight), we represent it in a couple of reduced forms.
+   Suppose a determinized-state is a collection of (state, weight) pairs; call
+   this the "canonical representation".  Note: these collections are always
+   normalized to remove any common weight and string part.  Define end-states as
+   the subset of states that have an arc out of them with a label on, or are
+   final.  If we represent a determinized-state a the set of just its (end-state,
+   weight) pairs, this will be a valid and more compact representation, and will
+   lead to a smaller set of determinized states (like early minimization).  Call
+   this collection of (end-state, weight) pairs the "minimal representation".  As
+   a mechanism to reduce compute, we can also consider another representation.
+   In the determinization algorithm, we start off with a set of (begin-state,
+   weight) pairs (where the "begin-states" are initial or have a label on the
+   transition into them), and the "canonical representation" consists of the
+   epsilon-closure of this set (i.e. follow epsilons).  Call this set of
+   (begin-state, weight) pairs, appropriately normalized, the "initial
+   representation".  If two initial representations are the same, the "canonical
+   representation" and hence the "minimal representation" will be the same.  We
+   can use this to reduce compute.  Note that if two initial representations are
+   different, this does not preclude the other representations from being the same.
+
+*/
+
+
+struct DeterminizeLatticePrunedOptions {
+  float delta; // A small offset used to measure equality of weights.
+  int max_mem; // If >0, determinization will fail and return false
+  // when the algorithm's (approximate) memory consumption crosses this threshold.
+  int max_loop; // If >0, can be used to detect non-determinizable input
+  // (a case that wouldn't be caught by max_mem).
+  int max_states;
+  int max_arcs;
+  float retry_cutoff;
+  DeterminizeLatticePrunedOptions(): delta(kDelta),
+                                     max_mem(-1),
+                                     max_loop(-1),
+                                     max_states(-1),
+                                     max_arcs(-1),
+                                     retry_cutoff(0.5) { }
+  void Register (kaldi::OptionsItf *opts) {
+    opts->Register("delta", &delta, "Tolerance used in determinization");
+    opts->Register("max-mem", &max_mem, "Maximum approximate memory usage in "
+                   "determinization (real usage might be many times this)");
+    opts->Register("max-arcs", &max_arcs, "Maximum number of arcs in "
+                   "output FST (total, not per state");
+    opts->Register("max-states", &max_states, "Maximum number of arcs in output "
+                   "FST (total, not per state");
+    opts->Register("max-loop", &max_loop, "Option used to detect a particular "
+                   "type of determinization failure, typically due to invalid input "
+                   "(e.g., negative-cost loops)");
+    opts->Register("retry-cutoff", &retry_cutoff, "Controls pruning un-determinized "
+                   "lattice and retrying determinization: if effective-beam < "
+                   "retry-cutoff * beam, we prune the raw lattice and retry.  Avoids "
+                   "ever getting empty output for long segments.");
+  }
+};
+
+struct DeterminizeLatticePhonePrunedOptions {
+  // delta: a small offset used to measure equality of weights.
+  float delta;
+  // max_mem: if > 0, determinization will fail and return false when the
+  // algorithm's (approximate) memory consumption crosses this threshold.
+  int max_mem;
+  // phone_determinize: if true, do a first pass determinization on both phones
+  // and words.
+  bool phone_determinize;
+  // word_determinize: if true, do a second pass determinization on words only.
+  bool word_determinize;
+  // minimize: if true, push and minimize after determinization.
+  bool minimize;
+  DeterminizeLatticePhonePrunedOptions(): delta(kDelta),
+                                          max_mem(50000000),
+                                          phone_determinize(true),
+                                          word_determinize(true),
+                                          minimize(false) {}
+  void Register (kaldi::OptionsItf *opts) {
+    opts->Register("delta", &delta, "Tolerance used in determinization");
+    opts->Register("max-mem", &max_mem, "Maximum approximate memory usage in "
+                   "determinization (real usage might be many times this).");
+    opts->Register("phone-determinize", &phone_determinize, "If true, do an "
+                   "initial pass of determinization on both phones and words (see"
+                   " also --word-determinize)");
+    opts->Register("word-determinize", &word_determinize, "If true, do a second "
+                   "pass of determinization on words only (see also "
+                   "--phone-determinize)");
+    opts->Register("minimize", &minimize, "If true, push and minimize after "
+                   "determinization.");
+  }
+};
+
+/**
+    This function implements the normal version of DeterminizeLattice, in which the
+    output strings are represented using sequences of arcs, where all but the
+    first one has an epsilon on the input side.  It also prunes using the beam
+    in the "prune" parameter.  The input FST must be topologically sorted in order
+    for the algorithm to work. For efficiency it is recommended to sort ilabel as well.
+    Returns true on success, and false if it had to terminate the determinization
+    earlier than specified by the "prune" beam-- that is, if it terminated because
+    of the max_mem, max_loop or max_arcs constraints in the options.
+    CAUTION: you may want to use the version below which outputs to CompactLattice.
+*/
+template<class Weight>
+bool DeterminizeLatticePruned(
+    const ExpandedFst<ArcTpl<Weight> > &ifst,
+    double prune,
+    MutableFst<ArcTpl<Weight> > *ofst,
+    DeterminizeLatticePrunedOptions opts = DeterminizeLatticePrunedOptions());
+
+
+/*  This is a version of DeterminizeLattice with a slightly more "natural" output format,
+    where the output sequences are encoded using the CompactLatticeArcTpl template
+    (i.e. the sequences of output symbols are represented directly as strings The input
+    FST must be topologically sorted in order for the algorithm to work. For efficiency
+    it is recommended to sort the ilabel for the input FST as well.
+    Returns true on normal success, and false if it had to terminate the determinization
+    earlier than specified by the "prune" beam-- that is, if it terminated because
+    of the max_mem, max_loop or max_arcs constraints in the options.
+    CAUTION: if Lattice is the input, you need to Invert() before calling this,
+    so words are on the input side.
+*/
+template<class Weight, class IntType>
+bool DeterminizeLatticePruned(
+    const ExpandedFst<ArcTpl<Weight> >&ifst,
+    double prune,
+    MutableFst<ArcTpl<CompactLatticeWeightTpl<Weight, IntType> > > *ofst,
+    DeterminizeLatticePrunedOptions opts = DeterminizeLatticePrunedOptions());
+
+/** This function takes in lattices and inserts phones at phone boundaries. It
+    uses the transition model to work out the transition_id to phone map. The
+    returning value is the starting index of the phone label. Typically we pick
+    (maximum_output_label_index + 1) as this value. The inserted phones are then
+    mapped to (returning_value + original_phone_label) in the new lattice. The
+    returning value will be used by DeterminizeLatticeDeletePhones() where it
+    works out the phones according to this value.
+*/
+template<class Weight>
+typename ArcTpl<Weight>::Label DeterminizeLatticeInsertPhones(
+    const kaldi::TransitionInformation &trans_model,
+    MutableFst<ArcTpl<Weight> > *fst);
+
+/** This function takes in lattices and deletes "phones" from them. The "phones"
+    here are actually any label that is larger than first_phone_label because
+    when we insert phones into the lattice, we map the original phone label to
+    (first_phone_label + original_phone_label). It is supposed to be used
+    together with DeterminizeLatticeInsertPhones()
+*/
+template<class Weight>
+void DeterminizeLatticeDeletePhones(
+    typename ArcTpl<Weight>::Label first_phone_label,
+    MutableFst<ArcTpl<Weight> > *fst);
+
+/** This function is a wrapper of DeterminizeLatticePhonePrunedFirstPass() and
+    DeterminizeLatticePruned(). If --phone-determinize is set to true, it first
+    calls DeterminizeLatticePhonePrunedFirstPass() to do the initial pass of
+    determinization on the phone + word lattices. If --word-determinize is set
+    true, it then does a second pass of determinization on the word lattices by
+    calling DeterminizeLatticePruned(). If both are set to false, then it gives
+    a warning and copying the lattices without determinization.
+
+    Note: the point of doing first a phone-level determinization pass and then
+    a word-level determinization pass is that it allows us to determinize
+    deeper lattices without "failing early" and returning a too-small lattice
+    due to the max-mem constraint.  The result should be the same as word-level
+    determinization in general, but for deeper lattices it is a bit faster,
+    despite the fact that we now have two passes of determinization by default.
+*/
+template<class Weight, class IntType>
+bool DeterminizeLatticePhonePruned(
+    const kaldi::TransitionInformation &trans_model,
+    const ExpandedFst<ArcTpl<Weight> > &ifst,
+    double prune,
+    MutableFst<ArcTpl<CompactLatticeWeightTpl<Weight, IntType> > > *ofst,
+    DeterminizeLatticePhonePrunedOptions opts
+      = DeterminizeLatticePhonePrunedOptions());
+
+/** "Destructive" version of DeterminizeLatticePhonePruned() where the input
+    lattice might be changed.
+*/
+template<class Weight, class IntType>
+bool DeterminizeLatticePhonePruned(
+    const kaldi::TransitionInformation &trans_model,
+    MutableFst<ArcTpl<Weight> > *ifst,
+    double prune,
+    MutableFst<ArcTpl<CompactLatticeWeightTpl<Weight, IntType> > > *ofst,
+    DeterminizeLatticePhonePrunedOptions opts
+      = DeterminizeLatticePhonePrunedOptions());
+
+/** This function is a wrapper of DeterminizeLatticePhonePruned() that works for
+    Lattice type FSTs.  It simplifies the calling process by calling
+    TopSort() Invert() and ArcSort() for you.
+    Unlike other determinization routines, the function
+    requires "ifst" to have transition-id's on the input side and words on the
+    output side.
+    This function can be used as the top-level interface to all the determinization
+    code.
+*/
+bool DeterminizeLatticePhonePrunedWrapper(
+    const kaldi::TransitionInformation &trans_model,
+    MutableFst<kaldi::LatticeArc> *ifst,
+    double prune,
+    MutableFst<kaldi::CompactLatticeArc> *ofst,
+    DeterminizeLatticePhonePrunedOptions opts
+      = DeterminizeLatticePhonePrunedOptions());
+
+/// @} end "addtogroup fst_extensions"
+
+} // end namespace fst
+
+#endif

speechx/speechx/kaldi/lat/kaldi-lattice.cc

@@ -0,0 +1,506 @@
+// lat/kaldi-lattice.cc
+
+// Copyright 2009-2011     Microsoft Corporation
+//                2013     Johns Hopkins University (author: Daniel Povey)
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+
+#include "lat/kaldi-lattice.h"
+#include "fst/script/print-impl.h"
+
+namespace kaldi {
+
+/// Converts lattice types if necessary, deleting its input.
+template<class OrigWeightType>
+CompactLattice* ConvertToCompactLattice(fst::VectorFst<OrigWeightType> *ifst) {
+  if (!ifst) return NULL;
+  CompactLattice *ofst = new CompactLattice();
+  ConvertLattice(*ifst, ofst);
+  delete ifst;
+  return ofst;
+}
+
+// This overrides the template if there is no type conversion going on
+// (for efficiency).
+template<>
+CompactLattice* ConvertToCompactLattice(CompactLattice *ifst) {
+  return ifst;
+}
+
+/// Converts lattice types if necessary, deleting its input.
+template<class OrigWeightType>
+Lattice* ConvertToLattice(fst::VectorFst<OrigWeightType> *ifst) {
+  if (!ifst) return NULL;
+  Lattice *ofst = new Lattice();
+  ConvertLattice(*ifst, ofst);
+  delete ifst;
+  return ofst;
+}
+
+// This overrides the template if there is no type conversion going on
+// (for efficiency).
+template<>
+Lattice* ConvertToLattice(Lattice *ifst) {
+  return ifst;
+}
+
+
+bool WriteCompactLattice(std::ostream &os, bool binary,
+                         const CompactLattice &t) {
+  if (binary) {
+    fst::FstWriteOptions opts;
+    // Leave all the options default.  Normally these lattices wouldn't have any
+    // osymbols/isymbols so no point directing it not to write them (who knows what
+    // we'd want to if we had them).
+    return t.Write(os, opts);
+  } else {
+    // Text-mode output.  Note: we expect that t.InputSymbols() and
+    // t.OutputSymbols() would always return NULL.  The corresponding input
+    // routine would not work if the FST actually had symbols attached.
+    // Write a newline after the key, so the first line of the FST appears
+    // on its own line.
+    os << '\n';
+    bool acceptor = true, write_one = false;
+    fst::FstPrinter<CompactLatticeArc> printer(t, t.InputSymbols(),
+                                               t.OutputSymbols(),
+                                               NULL, acceptor, write_one, "\t");
+    printer.Print(&os, "<unknown>");
+    if (os.fail())
+      KALDI_WARN << "Stream failure detected.";
+    // Write another newline as a terminating character.  The read routine will
+    // detect this [this is a Kaldi mechanism, not somethig in the original
+    // OpenFst code].
+    os << '\n';
+    return os.good();
+  }
+}
+
+/// LatticeReader provides (static) functions for reading both Lattice
+/// and CompactLattice, in text form.
+class LatticeReader {
+  typedef LatticeArc Arc;
+  typedef LatticeWeight Weight;
+  typedef CompactLatticeArc CArc;
+  typedef CompactLatticeWeight CWeight;
+  typedef Arc::Label Label;
+  typedef Arc::StateId StateId;
+ public:
+  // everything is static in this class.
+
+  /** This function reads from the FST text format; it does not know in advance
+      whether it's a Lattice or CompactLattice in the stream so it tries to
+      read both formats until it becomes clear which is the correct one.
+  */
+  static std::pair<Lattice*, CompactLattice*> ReadText(
+      std::istream &is) {
+    typedef std::pair<Lattice*, CompactLattice*> PairT;
+    using std::string;
+    using std::vector;
+    Lattice *fst = new Lattice();
+    CompactLattice *cfst = new CompactLattice();
+    string line;
+    size_t nline = 0;
+    string separator = FLAGS_fst_field_separator + "\r\n";
+    while (std::getline(is, line)) {
+      nline++;
+      vector<string> col;
+      // on Windows we'll write in text and read in binary mode.
+      SplitStringToVector(line, separator.c_str(), true, &col);
+      if (col.size() == 0) break; // Empty line is a signal to stop, in our
+      // archive format.
+      if (col.size() > 5) {
+        KALDI_WARN << "Reading lattice: bad line in FST: " << line;
+        delete fst;
+        delete cfst;
+        return PairT(static_cast<Lattice*>(NULL),
+                     static_cast<CompactLattice*>(NULL));
+      }
+      StateId s;
+      if (!ConvertStringToInteger(col[0], &s)) {
+        KALDI_WARN << "FstCompiler: bad line in FST: " << line;
+        delete fst;
+        delete cfst;
+        return PairT(static_cast<Lattice*>(NULL),
+                     static_cast<CompactLattice*>(NULL));
+      }
+      if (fst)
+        while (s >= fst->NumStates())
+          fst->AddState();
+      if (cfst)
+        while (s >= cfst->NumStates())
+          cfst->AddState();
+      if (nline == 1) {
+        if (fst) fst->SetStart(s);
+        if (cfst) cfst->SetStart(s);
+      }
+
+      if (fst) { // we still have fst; try to read that arc.
+        bool ok = true;
+        Arc arc;
+        Weight w;
+        StateId d = s;
+        switch (col.size()) {
+          case 1 :
+            fst->SetFinal(s, Weight::One());
+            break;
+          case 2:
+            if (!StrToWeight(col[1], true, &w)) ok = false;
+            else fst->SetFinal(s, w);
+            break;
+          case 3: // 3 columns not ok for Lattice format; it's not an acceptor.
+            ok = false;
+            break;
+          case 4:
+            ok = ConvertStringToInteger(col[1], &arc.nextstate) &&
+                ConvertStringToInteger(col[2], &arc.ilabel) &&
+                ConvertStringToInteger(col[3], &arc.olabel);
+            if (ok) {
+              d = arc.nextstate;
+              arc.weight = Weight::One();
+              fst->AddArc(s, arc);
+            }
+            break;
+          case 5:
+            ok = ConvertStringToInteger(col[1], &arc.nextstate) &&
+                ConvertStringToInteger(col[2], &arc.ilabel) &&
+                ConvertStringToInteger(col[3], &arc.olabel) &&
+                StrToWeight(col[4], false, &arc.weight);
+            if (ok) {
+              d = arc.nextstate;
+              fst->AddArc(s, arc);
+            }
+            break;
+          default:
+            ok = false;
+        }
+        while (d >= fst->NumStates())
+          fst->AddState();
+        if (!ok) {
+          delete fst;
+          fst = NULL;
+        }
+      }
+      if (cfst) {
+        bool ok = true;
+        CArc arc;
+        CWeight w;
+        StateId d = s;
+        switch (col.size()) {
+          case 1 :
+            cfst->SetFinal(s, CWeight::One());
+            break;
+          case 2:
+            if (!StrToCWeight(col[1], true, &w)) ok = false;
+            else cfst->SetFinal(s, w);
+            break;
+          case 3: // compact-lattice is acceptor format: state, next-state, label.
+            ok = ConvertStringToInteger(col[1], &arc.nextstate) &&
+                ConvertStringToInteger(col[2], &arc.ilabel);
+            if (ok) {
+              d = arc.nextstate;
+              arc.olabel = arc.ilabel;
+              arc.weight = CWeight::One();
+              cfst->AddArc(s, arc);
+            }
+            break;
+          case 4:
+            ok = ConvertStringToInteger(col[1], &arc.nextstate) &&
+                ConvertStringToInteger(col[2], &arc.ilabel) &&
+                StrToCWeight(col[3], false, &arc.weight);
+            if (ok) {
+              d = arc.nextstate;
+              arc.olabel = arc.ilabel;
+              cfst->AddArc(s, arc);
+            }
+            break;
+          case 5: default:
+            ok = false;
+        }
+        while (d >= cfst->NumStates())
+          cfst->AddState();
+        if (!ok) {
+          delete cfst;
+          cfst = NULL;
+        }
+      }
+      if (!fst && !cfst) {
+        KALDI_WARN << "Bad line in lattice text format: " << line;
+        // read until we get an empty line, so at least we
+        // have a chance to read the next one (although this might
+        // be a bit futile since the calling code will get unhappy
+        // about failing to read this one.
+        while (std::getline(is, line)) {
+          SplitStringToVector(line, separator.c_str(), true, &col);
+          if (col.empty()) break;
+        }
+        return PairT(static_cast<Lattice*>(NULL),
+                     static_cast<CompactLattice*>(NULL));
+      }
+    }
+    return PairT(fst, cfst);
+  }
+
+  static bool StrToWeight(const std::string &s, bool allow_zero, Weight *w) {
+    std::istringstream strm(s);
+    strm >> *w;
+    if (!strm || (!allow_zero && *w == Weight::Zero())) {
+      return false;
+    }
+    return true;
+  }
+
+  static  bool StrToCWeight(const std::string &s, bool allow_zero, CWeight *w) {
+    std::istringstream strm(s);
+    strm >> *w;
+    if (!strm || (!allow_zero && *w == CWeight::Zero())) {
+      return false;
+    }
+    return true;
+  }
+};
+
+
+CompactLattice *ReadCompactLatticeText(std::istream &is) {
+  std::pair<Lattice*, CompactLattice*> lat_pair = LatticeReader::ReadText(is);
+  if (lat_pair.second != NULL) {
+    delete lat_pair.first;
+    return lat_pair.second;
+  } else if (lat_pair.first != NULL) {
+    // note: ConvertToCompactLattice frees its input.
+    return ConvertToCompactLattice(lat_pair.first);
+  } else {
+    return NULL;
+  }
+}
+
+
+Lattice *ReadLatticeText(std::istream &is) {
+  std::pair<Lattice*, CompactLattice*> lat_pair = LatticeReader::ReadText(is);
+  if (lat_pair.first != NULL) {
+    delete lat_pair.second;
+    return lat_pair.first;
+  } else if (lat_pair.second != NULL) {
+    // note: ConvertToLattice frees its input.
+    return ConvertToLattice(lat_pair.second);
+  } else {
+    return NULL;
+  }
+}
+
+bool ReadCompactLattice(std::istream &is, bool binary,
+                        CompactLattice **clat) {
+  KALDI_ASSERT(*clat == NULL);
+  if (binary) {
+    fst::FstHeader hdr;
+    if (!hdr.Read(is, "<unknown>")) {
+      KALDI_WARN << "Reading compact lattice: error reading FST header.";
+      return false;
+    }
+    if (hdr.FstType() != "vector") {
+      KALDI_WARN << "Reading compact lattice: unsupported FST type: "
+                 << hdr.FstType();
+      return false;
+    }
+    fst::FstReadOptions ropts("<unspecified>",
+                              &hdr);
+
+    typedef fst::CompactLatticeWeightTpl<fst::LatticeWeightTpl<float>, int32> T1;
+    typedef fst::CompactLatticeWeightTpl<fst::LatticeWeightTpl<double>, int32> T2;
+    typedef fst::LatticeWeightTpl<float> T3;
+    typedef fst::LatticeWeightTpl<double> T4;
+    typedef fst::VectorFst<fst::ArcTpl<T1> > F1;
+    typedef fst::VectorFst<fst::ArcTpl<T2> > F2;
+    typedef fst::VectorFst<fst::ArcTpl<T3> > F3;
+    typedef fst::VectorFst<fst::ArcTpl<T4> > F4;
+
+    CompactLattice *ans = NULL;
+    if (hdr.ArcType() == T1::Type()) {
+      ans = ConvertToCompactLattice(F1::Read(is, ropts));
+    } else if (hdr.ArcType() == T2::Type()) {
+      ans = ConvertToCompactLattice(F2::Read(is, ropts));
+    } else if (hdr.ArcType() == T3::Type()) {
+      ans = ConvertToCompactLattice(F3::Read(is, ropts));
+    } else if (hdr.ArcType() == T4::Type()) {
+      ans = ConvertToCompactLattice(F4::Read(is, ropts));
+    } else {
+      KALDI_WARN << "FST with arc type " << hdr.ArcType()
+                 << " cannot be converted to CompactLattice.\n";
+      return false;
+    }
+    if (ans == NULL) {
+      KALDI_WARN << "Error reading compact lattice (after reading header).";
+      return false;
+    }
+    *clat = ans;
+    return true;
+  } else {
+    // The next line would normally consume the \r on Windows, plus any
+    // extra spaces that might have got in there somehow.
+    while (std::isspace(is.peek()) && is.peek() != '\n') is.get();
+    if (is.peek() == '\n') is.get(); // consume the newline.
+    else { // saw spaces but no newline.. this is not expected.
+      KALDI_WARN << "Reading compact lattice: unexpected sequence of spaces "
+                 << " at file position " << is.tellg();
+      return false;
+    }
+    *clat = ReadCompactLatticeText(is); // that routine will warn on error.
+    return (*clat != NULL);
+  }
+}
+
+
+bool CompactLatticeHolder::Read(std::istream &is) {
+  Clear(); // in case anything currently stored.
+  int c = is.peek();
+  if (c == -1) {
+    KALDI_WARN << "End of stream detected reading CompactLattice.";
+    return false;
+  } else if (isspace(c)) { // The text form of the lattice begins
+    // with space (normally, '\n'), so this means it's text (the binary form
+    // cannot begin with space because it starts with the FST Type() which is not
+    // space).
+    return ReadCompactLattice(is, false, &t_);
+  } else if (c != 214) { // 214 is first char of FST magic number,
+    // on little-endian machines which is all we support (\326 octal)
+    KALDI_WARN << "Reading compact lattice: does not appear to be an FST "
+               << " [non-space but no magic number detected], file pos is "
+               << is.tellg();
+    return false;
+  } else {
+    return ReadCompactLattice(is, true, &t_);
+  }
+}
+
+bool WriteLattice(std::ostream &os, bool binary, const Lattice &t) {
+  if (binary) {
+    fst::FstWriteOptions opts;
+    // Leave all the options default.  Normally these lattices wouldn't have any
+    // osymbols/isymbols so no point directing it not to write them (who knows what
+    // we'd want to do if we had them).
+    return t.Write(os, opts);
+  } else {
+    // Text-mode output.  Note: we expect that t.InputSymbols() and
+    // t.OutputSymbols() would always return NULL.  The corresponding input
+    // routine would not work if the FST actually had symbols attached.
+    // Write a newline after the key, so the first line of the FST appears
+    // on its own line.
+    os << '\n';
+    bool acceptor = false, write_one = false;
+    fst::FstPrinter<LatticeArc> printer(t, t.InputSymbols(),
+                                        t.OutputSymbols(),
+                                        NULL, acceptor, write_one, "\t");
+    printer.Print(&os, "<unknown>");
+    if (os.fail())
+      KALDI_WARN << "Stream failure detected.";
+    // Write another newline as a terminating character.  The read routine will
+    // detect this [this is a Kaldi mechanism, not somethig in the original
+    // OpenFst code].
+    os << '\n';
+    return os.good();
+  }
+}
+
+bool ReadLattice(std::istream &is, bool binary,
+                 Lattice **lat) {
+  KALDI_ASSERT(*lat == NULL);
+  if (binary) {
+    fst::FstHeader hdr;
+    if (!hdr.Read(is, "<unknown>")) {
+      KALDI_WARN << "Reading lattice: error reading FST header.";
+      return false;
+    }
+    if (hdr.FstType() != "vector") {
+      KALDI_WARN << "Reading lattice: unsupported FST type: "
+                 << hdr.FstType();
+      return false;
+    }
+    fst::FstReadOptions ropts("<unspecified>",
+                              &hdr);
+
+    typedef fst::CompactLatticeWeightTpl<fst::LatticeWeightTpl<float>, int32> T1;
+    typedef fst::CompactLatticeWeightTpl<fst::LatticeWeightTpl<double>, int32> T2;
+    typedef fst::LatticeWeightTpl<float> T3;
+    typedef fst::LatticeWeightTpl<double> T4;
+    typedef fst::VectorFst<fst::ArcTpl<T1> > F1;
+    typedef fst::VectorFst<fst::ArcTpl<T2> > F2;
+    typedef fst::VectorFst<fst::ArcTpl<T3> > F3;
+    typedef fst::VectorFst<fst::ArcTpl<T4> > F4;
+
+    Lattice *ans = NULL;
+    if (hdr.ArcType() == T1::Type()) {
+      ans = ConvertToLattice(F1::Read(is, ropts));
+    } else if (hdr.ArcType() == T2::Type()) {
+      ans = ConvertToLattice(F2::Read(is, ropts));
+    } else if (hdr.ArcType() == T3::Type()) {
+      ans = ConvertToLattice(F3::Read(is, ropts));
+    } else if (hdr.ArcType() == T4::Type()) {
+      ans = ConvertToLattice(F4::Read(is, ropts));
+    } else {
+      KALDI_WARN << "FST with arc type " << hdr.ArcType()
+                 << " cannot be converted to Lattice.\n";
+      return false;
+    }
+    if (ans == NULL) {
+      KALDI_WARN << "Error reading lattice (after reading header).";
+      return false;
+    }
+    *lat = ans;
+    return true;
+  } else {
+    // The next line would normally consume the \r on Windows, plus any
+    // extra spaces that might have got in there somehow.
+    while (std::isspace(is.peek()) && is.peek() != '\n') is.get();
+    if (is.peek() == '\n') is.get(); // consume the newline.
+    else { // saw spaces but no newline.. this is not expected.
+      KALDI_WARN << "Reading compact lattice: unexpected sequence of spaces "
+                 << " at file position " << is.tellg();
+      return false;
+    }
+    *lat = ReadLatticeText(is); // that routine will warn on error.
+    return (*lat != NULL);
+  }
+}
+
+
+/* Since we don't write the binary headers for this type of holder,
+   we use a different method to work out whether we're in binary mode.
+ */
+bool LatticeHolder::Read(std::istream &is) {
+  Clear(); // in case anything currently stored.
+  int c = is.peek();
+  if (c == -1) {
+    KALDI_WARN << "End of stream detected reading Lattice.";
+    return false;
+  } else if (isspace(c)) { // The text form of the lattice begins
+    // with space (normally, '\n'), so this means it's text (the binary form
+    // cannot begin with space because it starts with the FST Type() which is not
+    // space).
+    return ReadLattice(is, false, &t_);
+  } else if (c != 214) { // 214 is first char of FST magic number,
+    // on little-endian machines which is all we support (\326 octal)
+    KALDI_WARN << "Reading compact lattice: does not appear to be an FST "
+               << " [non-space but no magic number detected], file pos is "
+               << is.tellg();
+    return false;
+  } else {
+    return ReadLattice(is, true, &t_);
+  }
+}
+
+
+
+} // end namespace kaldi

speechx/speechx/kaldi/lat/kaldi-lattice.h

@@ -0,0 +1,156 @@
+// lat/kaldi-lattice.h
+
+// Copyright 2009-2011  Microsoft Corporation
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+
+#ifndef KALDI_LAT_KALDI_LATTICE_H_
+#define KALDI_LAT_KALDI_LATTICE_H_
+
+#include "fstext/fstext-lib.h"
+#include "base/kaldi-common.h"
+#include "util/common-utils.h"
+
+
+namespace kaldi {
+// will import some things above...
+
+typedef fst::LatticeWeightTpl<BaseFloat> LatticeWeight;
+
+// careful: kaldi::int32 is not always the same C type as fst::int32
+typedef fst::CompactLatticeWeightTpl<LatticeWeight, int32> CompactLatticeWeight;
+
+typedef fst::CompactLatticeWeightCommonDivisorTpl<LatticeWeight, int32>
+  CompactLatticeWeightCommonDivisor;
+
+typedef fst::ArcTpl<LatticeWeight> LatticeArc;
+
+typedef fst::ArcTpl<CompactLatticeWeight> CompactLatticeArc;
+
+typedef fst::VectorFst<LatticeArc> Lattice;
+
+typedef fst::VectorFst<CompactLatticeArc> CompactLattice;
+
+// The following functions for writing and reading lattices in binary or text
+// form are provided here in case you need to include lattices in larger,
+// Kaldi-type objects with their own Read and Write functions.  Caution: these
+// functions return false on stream failure rather than throwing an exception as
+// most similar Kaldi functions would do.
+
+bool WriteCompactLattice(std::ostream &os, bool binary,
+                         const CompactLattice &clat);
+bool WriteLattice(std::ostream &os, bool binary,
+                  const Lattice &lat);
+
+// the following function requires that *clat be
+// NULL when called.
+bool ReadCompactLattice(std::istream &is, bool binary,
+                        CompactLattice **clat);
+// the following function requires that *lat be
+// NULL when called.
+bool ReadLattice(std::istream &is, bool binary,
+                 Lattice **lat);
+
+
+class CompactLatticeHolder {
+ public:
+  typedef CompactLattice T;
+
+  CompactLatticeHolder() { t_ = NULL; }
+
+  static bool Write(std::ostream &os, bool binary, const T &t) {
+    // Note: we don't include the binary-mode header when writing
+    // this object to disk; this ensures that if we write to single
+    // files, the result can be read by OpenFst.
+    return WriteCompactLattice(os, binary, t);
+  }
+
+  bool Read(std::istream &is);
+
+  static bool IsReadInBinary() { return true; }
+
+  T &Value() {
+    KALDI_ASSERT(t_ != NULL && "Called Value() on empty CompactLatticeHolder");
+    return *t_;
+  }
+
+  void Clear() { delete t_; t_ = NULL; }
+
+  void Swap(CompactLatticeHolder *other) {
+    std::swap(t_, other->t_);
+  }
+
+  bool ExtractRange(const CompactLatticeHolder &other, const std::string &range) {
+    KALDI_ERR << "ExtractRange is not defined for this type of holder.";
+    return false;
+  }
+
+  ~CompactLatticeHolder() { Clear(); }
+ private:
+  T *t_;
+};
+
+class LatticeHolder {
+ public:
+  typedef Lattice T;
+
+  LatticeHolder() { t_ = NULL; }
+
+  static bool Write(std::ostream &os, bool binary, const T &t) {
+    // Note: we don't include the binary-mode header when writing
+    // this object to disk; this ensures that if we write to single
+    // files, the result can be read by OpenFst.
+    return WriteLattice(os, binary, t);
+  }
+
+  bool Read(std::istream &is);
+
+  static bool IsReadInBinary() { return true; }
+
+  T &Value() {
+    KALDI_ASSERT(t_ != NULL && "Called Value() on empty LatticeHolder");
+    return *t_;
+  }
+
+  void Clear() {  delete t_; t_ = NULL; }
+
+  void Swap(LatticeHolder *other) {
+    std::swap(t_, other->t_);
+  }
+
+  bool ExtractRange(const LatticeHolder &other, const std::string &range) {
+    KALDI_ERR << "ExtractRange is not defined for this type of holder.";
+    return false;
+  }
+
+  ~LatticeHolder() { Clear(); }
+ private:
+  T *t_;
+};
+
+typedef TableWriter<LatticeHolder> LatticeWriter;
+typedef SequentialTableReader<LatticeHolder> SequentialLatticeReader;
+typedef RandomAccessTableReader<LatticeHolder> RandomAccessLatticeReader;
+
+typedef TableWriter<CompactLatticeHolder> CompactLatticeWriter;
+typedef SequentialTableReader<CompactLatticeHolder> SequentialCompactLatticeReader;
+typedef RandomAccessTableReader<CompactLatticeHolder> RandomAccessCompactLatticeReader;
+
+
+} // namespace kaldi
+
+#endif  // KALDI_LAT_KALDI_LATTICE_H_

speechx/speechx/kaldi/lat/lattice-functions.h

@@ -0,0 +1,402 @@
+// lat/lattice-functions.h
+
+// Copyright 2009-2012   Saarland University (author: Arnab Ghoshal)
+//           2012-2013   Johns Hopkins University (Author: Daniel Povey);
+//                       Bagher BabaAli
+//                2014   Guoguo Chen
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+
+#ifndef KALDI_LAT_LATTICE_FUNCTIONS_H_
+#define KALDI_LAT_LATTICE_FUNCTIONS_H_
+
+#include <vector>
+#include <map>
+
+#include "base/kaldi-common.h"
+#include "fstext/fstext-lib.h"
+#include "itf/decodable-itf.h"
+#include "itf/transition-information.h"
+#include "lat/kaldi-lattice.h"
+
+namespace kaldi {
+
+// Redundant with the typedef in hmm/posterior.h. We want functions
+// using the Posterior type to be usable without a dependency on the
+// hmm library.
+typedef std::vector<std::vector<std::pair<int32, BaseFloat> > > Posterior;
+
+/**
+   This function extracts the per-frame log likelihoods from a linear
+   lattice (which we refer to as an 'nbest' lattice elsewhere in Kaldi code).
+   The dimension of *per_frame_loglikes will be set to the
+   number of input symbols in 'nbest'.  The elements of
+   '*per_frame_loglikes' will be set to the .Value2() elements of the lattice
+   weights, which represent the acoustic costs; you may want to scale this
+   vector afterward by -1/acoustic_scale to get the original loglikes.
+   If there are acoustic costs on input-epsilon arcs or the final-prob in 'nbest'
+   (and this should not normally be the case in situations where it makes
+   sense to call this function), they will be included to the cost of the
+   preceding input symbol, or the following input symbol for input-epsilons
+   encountered prior to any input symbol.  If 'nbest' has no input symbols,
+   'per_frame_loglikes' will be set to the empty vector.
+**/
+void GetPerFrameAcousticCosts(const Lattice &nbest,
+                              Vector<BaseFloat> *per_frame_loglikes);
+
+/// This function iterates over the states of a topologically sorted lattice and
+/// counts the time instance corresponding to each state. The times are returned
+/// in a vector of integers 'times' which is resized to have a size equal to the
+/// number of states in the lattice. The function also returns the maximum time
+/// in the lattice (this will equal the number of frames in the file).
+int32 LatticeStateTimes(const Lattice &lat, std::vector<int32> *times);
+
+/// As LatticeStateTimes, but in the CompactLattice format.  Note: must
+/// be topologically sorted.  Returns length of the utterance in frames, which
+/// might not be the same as the maximum time in the lattice, due to frames
+/// in the final-prob.
+int32 CompactLatticeStateTimes(const CompactLattice &clat,
+                               std::vector<int32> *times);
+
+/// This function does the forward-backward over lattices and computes the
+/// posterior probabilities of the arcs. It returns the total log-probability
+/// of the lattice.  The Posterior quantities contain pairs of (transition-id, weight)
+/// on each frame.
+/// If the pointer "acoustic_like_sum" is provided, this value is set to
+/// the sum over the arcs, of the posterior of the arc times the
+/// acoustic likelihood [i.e. negated acoustic score] on that link.
+/// This is used in combination with other quantities to work out
+/// the objective function in MMI discriminative training.
+BaseFloat LatticeForwardBackward(const Lattice &lat,
+                                 Posterior *arc_post,
+                                 double *acoustic_like_sum = NULL);
+
+// This function is something similar to LatticeForwardBackward(), but it is on
+// the CompactLattice lattice format. Also we only need the alpha in the forward
+// path, not the posteriors.
+bool ComputeCompactLatticeAlphas(const CompactLattice &lat,
+                                 std::vector<double> *alpha);
+
+// A sibling of the function CompactLatticeAlphas()... We compute the beta from
+// the backward path here.
+bool ComputeCompactLatticeBetas(const CompactLattice &lat,
+                                std::vector<double> *beta);
+
+
+// Computes (normal or Viterbi) alphas and betas; returns (total-prob, or
+// best-path negated cost) Note: in either case, the alphas and betas are
+// negated costs.  Requires that lat be topologically sorted.  This code
+// will work for either CompactLattice or Lattice.
+template<typename LatticeType>
+double ComputeLatticeAlphasAndBetas(const LatticeType &lat,
+                                    bool viterbi,
+                                    std::vector<double> *alpha,
+                                    std::vector<double> *beta);
+
+
+/// Topologically sort the compact lattice if not already topologically sorted.
+/// Will crash if the lattice cannot be topologically sorted.
+void TopSortCompactLatticeIfNeeded(CompactLattice *clat);
+
+
+/// Topologically sort the lattice if not already topologically sorted.
+/// Will crash if lattice cannot be topologically sorted.
+void TopSortLatticeIfNeeded(Lattice *clat);
+
+/// Returns the depth of the lattice, defined as the average number of arcs (or
+/// final-prob strings) crossing any given frame.  Returns 1 for empty lattices.
+/// Requires that clat is topologically sorted!
+BaseFloat CompactLatticeDepth(const CompactLattice &clat,
+                              int32 *num_frames = NULL);
+
+/// This function returns, for each frame, the number of arcs crossing that
+/// frame.
+void CompactLatticeDepthPerFrame(const CompactLattice &clat,
+                                 std::vector<int32> *depth_per_frame);
+
+
+/// This function limits the depth of the lattice, per frame: that means, it
+/// does not allow more than a specified number of arcs active on any given
+/// frame.  This can be used to reduce the size of the "very deep" portions of
+/// the lattice.
+void CompactLatticeLimitDepth(int32 max_arcs_per_frame,
+                              CompactLattice *clat);
+
+
+/// Given a lattice, and a transition model to map pdf-ids to phones,
+/// outputs for each frame the set of phones active on that frame.  If
+/// sil_phones (which must be sorted and uniq) is nonempty, it excludes
+/// phones in this list.
+void LatticeActivePhones(const Lattice &lat, const TransitionInformation &trans,
+                         const std::vector<int32> &sil_phones,
+                         std::vector<std::set<int32> > *active_phones);
+
+/// Given a lattice, and a transition model to map pdf-ids to phones,
+/// replace the output symbols (presumably words), with phones; we
+/// use the TransitionModel to work out the phone sequence.  Note
+/// that the phone labels are not exactly aligned with the phone
+/// boundaries.  We put a phone label to coincide with any transition
+/// to the final, nonemitting state of a phone (this state always exists,
+/// we ensure this in HmmTopology::Check()).  This would be the last
+/// transition-id in the phone if reordering is not done (but typically
+/// we do reorder).
+/// Also see PhoneAlignLattice, in phone-align-lattice.h.
+void ConvertLatticeToPhones(const TransitionInformation &trans_model,
+                            Lattice *lat);
+
+/// Prunes a lattice or compact lattice.  Returns true on success, false if
+/// there was some kind of failure.
+template<class LatticeType>
+bool PruneLattice(BaseFloat beam, LatticeType *lat);
+
+
+/// Given a lattice, and a transition model to map pdf-ids to phones,
+/// replace the sequences of transition-ids with sequences of phones.
+/// Note that this is different from ConvertLatticeToPhones, in that
+/// we replace the transition-ids not the words.
+void ConvertCompactLatticeToPhones(const TransitionInformation &trans_model,
+                                   CompactLattice *clat);
+
+/// Boosts LM probabilities by b * [number of frame errors]; equivalently, adds
+/// -b*[number of frame errors] to the graph-component of the cost of each arc/path.
+/// There is a frame error if a particular transition-id on a particular frame
+/// corresponds to a phone not matching transcription's alignment for that frame.
+/// This is used in "margin-inspired" discriminative training, esp. Boosted MMI.
+/// The TransitionInformation is used to map transition-ids in the lattice
+/// input-side to phones; the phones appearing in
+/// "silence_phones" are treated specially in that we replace the frame error f
+/// (either zero or 1) for a frame, with the minimum of f or max_silence_error.
+/// For the normal recipe, max_silence_error would be zero.
+/// Returns true on success, false if there was some kind of mismatch.
+/// At input, silence_phones must be sorted and unique.
+bool LatticeBoost(const TransitionInformation &trans,
+                  const std::vector<int32> &alignment,
+                  const std::vector<int32> &silence_phones,
+                  BaseFloat b,
+                  BaseFloat max_silence_error,
+                  Lattice *lat);
+
+
+/**
+   This function implements either the MPFE (minimum phone frame error) or SMBR
+   (state-level minimum bayes risk) forward-backward, depending on whether
+   "criterion" is "mpfe" or "smbr".  It returns the MPFE
+   criterion of SMBR criterion for this utterance, and outputs the posteriors (which
+   may be positive or negative) into "post".
+
+   @param [in] trans    The transition model. Used to map the
+                        transition-ids to phones or pdfs.
+   @param [in] silence_phones   A list of integer ids of silence phones. The
+                        silence frames i.e. the frames where num_ali
+                        corresponds to a silence phones are treated specially.
+                        The behavior is determined by 'one_silence_class'
+                        being false (traditional behavior) or true.
+                        Usually in our setup, several phones including
+                        the silence, vocalized noise, non-spoken noise
+                        and unk are treated as "silence phones"
+   @param [in] lat      The denominator lattice
+   @param [in] num_ali  The numerator alignment
+   @param [in] criterion    The objective function. Must be "mpfe" or "smbr"
+                        for MPFE (minimum phone frame error) or sMBR
+                        (state minimum bayes risk) training.
+   @param [in] one_silence_class   Determines how the silence frames are treated.
+                        Setting this to false gives the old traditional behavior,
+                        where the silence frames (according to num_ali) are
+                        treated as incorrect. However, this means that the
+                        insertions are not penalized by the objective.
+                        Setting this to true gives the new behaviour, where we
+                        treat silence as any other phone, except that all pdfs
+                        of silence phones are collapsed into a single class for
+                        the frame-error computation. This can possible reduce
+                        the insertions in the trained model. This is closer to
+                        the WER metric that we actually care about, since WER is
+                        generally computed after filtering out noises, but
+                        does penalize insertions.
+    @param [out] post   The "MBR posteriors" i.e. derivatives w.r.t to the
+                        pseudo log-likelihoods of states at each frame.
+*/
+BaseFloat LatticeForwardBackwardMpeVariants(
+    const TransitionInformation &trans,
+    const std::vector<int32> &silence_phones,
+    const Lattice &lat,
+    const std::vector<int32> &num_ali,
+    std::string criterion,
+    bool one_silence_class,
+    Posterior *post);
+
+/// This function takes a CompactLattice that should only contain a single
+/// linear sequence (e.g. derived from lattice-1best), and that should have been
+/// processed so that the arcs in the CompactLattice align correctly with the
+/// word boundaries (e.g. by lattice-align-words).  It outputs 3 vectors of the
+/// same size, which give, for each word in the lattice (in sequence), the word
+/// label and the begin time and length in frames.  This is done even for zero
+/// (epsilon) words, generally corresponding to optional silence-- if you don't
+/// want them, just ignore them in the output.
+/// This function will print a warning and return false, if the lattice
+/// did not have the correct format (e.g. if it is empty or it is not
+/// linear).
+bool CompactLatticeToWordAlignment(const CompactLattice &clat,
+                                   std::vector<int32> *words,
+                                   std::vector<int32> *begin_times,
+                                   std::vector<int32> *lengths);
+
+/// A form of the shortest-path/best-path algorithm that's specially coded for
+/// CompactLattice.  Requires that clat be acyclic.
+void CompactLatticeShortestPath(const CompactLattice &clat,
+                                CompactLattice *shortest_path);
+
+/// This function expands a CompactLattice to ensure high-probability paths
+/// have unique histories. Arcs with posteriors larger than epsilon get splitted.
+void ExpandCompactLattice(const CompactLattice &clat,
+                          double epsilon,
+                          CompactLattice *expand_clat);
+
+/// For each state, compute forward and backward best (viterbi) costs and its
+/// traceback states (for generating best paths later). The forward best cost
+/// for a state is the cost of the best path from the start state to the state.
+/// The traceback state of this state is its predecessor state in the best path.
+/// The backward best cost for a state is the cost of the best path from the
+/// state to a final one. Its traceback state is the successor state in the best
+/// path in the forward direction.
+/// Note: final weights of states are in backward_best_cost_and_pred.
+/// Requires the input CompactLattice clat be acyclic.
+typedef std::vector<std::pair<double,
+        CompactLatticeArc::StateId> > CostTraceType;
+void CompactLatticeBestCostsAndTracebacks(
+    const CompactLattice &clat,
+    CostTraceType *forward_best_cost_and_pred,
+    CostTraceType *backward_best_cost_and_pred);
+
+/// This function adds estimated neural language model scores of words in a
+/// minimal list of hypotheses that covers a lattice, to the graph scores on the
+/// arcs. The list of hypotheses are generated by latbin/lattice-path-cover.
+typedef unordered_map<std::pair<int32, int32>, double, PairHasher<int32> > MapT;
+void AddNnlmScoreToCompactLattice(const MapT &nnlm_scores,
+                                  CompactLattice *clat);
+
+/// This function add the word insertion penalty to graph score of each word
+/// in the compact lattice
+void AddWordInsPenToCompactLattice(BaseFloat word_ins_penalty,
+                                   CompactLattice *clat);
+
+/// This function *adds* the negated scores obtained from the Decodable object,
+/// to the acoustic scores on the arcs.  If you want to replace them, you should
+/// use ScaleCompactLattice to first set the acoustic scores to zero.  Returns
+/// true on success, false on error (typically some kind of mismatched inputs).
+bool RescoreCompactLattice(DecodableInterface *decodable,
+                           CompactLattice *clat);
+
+
+/// This function returns the number of words in the longest sentence in a
+/// CompactLattice (i.e. the the maximum of any path, of the count of
+/// olabels on that path).
+int32 LongestSentenceLength(const Lattice &lat);
+
+/// This function returns the number of words in the longest sentence in a
+/// CompactLattice, i.e. the the maximum of any path, of the count of
+/// labels on that path... note, in CompactLattice, the ilabels and olabels
+/// are identical because it is an acceptor.
+int32 LongestSentenceLength(const CompactLattice &lat);
+
+
+/// This function is like RescoreCompactLattice, but it is modified to avoid
+/// computing probabilities on most frames where all the pdf-ids are the same.
+/// (it needs the transition-model to work out whether two transition-ids map to
+/// the same pdf-id, and it assumes that the lattice has transition-ids on it).
+/// The naive thing would be to just set all probabilities to zero on frames
+/// where all the pdf-ids are the same (because this value won't affect the
+/// lattice posterior).  But this would become confusing when we compute
+/// corpus-level diagnostics such as the MMI objective function.  Instead,
+/// imagine speedup_factor = 100 (it must be >= 1.0)... with probability (1.0 /
+/// speedup_factor) we compute those likelihoods and multiply them by
+/// speedup_factor; otherwise we set them to zero.  This gives the right
+/// expected probability so our corpus-level diagnostics will be about right.
+bool RescoreCompactLatticeSpeedup(
+    const TransitionInformation &tmodel,
+    BaseFloat speedup_factor,
+    DecodableInterface *decodable,
+    CompactLattice *clat);
+
+
+/// This function *adds* the negated scores obtained from the Decodable object,
+/// to the acoustic scores on the arcs.  If you want to replace them, you should
+/// use ScaleCompactLattice to first set the acoustic scores to zero.  Returns
+/// true on success, false on error (e.g. some kind of mismatched inputs).
+/// The input labels, if nonzero, are interpreted as transition-ids or whatever
+/// other index the Decodable object expects.
+bool RescoreLattice(DecodableInterface *decodable,
+                    Lattice *lat);
+
+/// This function Composes a CompactLattice format lattice with a
+/// DeterministicOnDemandFst<fst::StdFst> format fst, and outputs another
+/// CompactLattice format lattice. The first element (the one that corresponds
+/// to LM weight) in CompactLatticeWeight is used for composition.
+///
+/// Note that the DeterministicOnDemandFst interface is not "const", therefore
+/// we cannot use "const" for <det_fst>.
+void ComposeCompactLatticeDeterministic(
+    const CompactLattice& clat,
+    fst::DeterministicOnDemandFst<fst::StdArc>* det_fst,
+    CompactLattice* composed_clat);
+
+/// This function computes the mapping from the pair 
+/// (frame-index, transition-id) to the pair 
+/// (sum-of-acoustic-scores, num-of-occurences) over all occurences of the 
+/// transition-id in that frame.
+/// frame-index in the lattice. 
+/// This function is useful for retaining the acoustic scores in a 
+/// non-compact lattice after a process like determinization where the 
+/// frame-level acoustic scores are typically lost.
+/// The function ReplaceAcousticScoresFromMap is used to restore the 
+/// acoustic scores computed by this function.
+///
+///   @param [in] lat   Input lattice. Expected to be top-sorted. Otherwise the 
+///                     function will crash. 
+///   @param [out] acoustic_scores  
+///                     Pointer to a map from the pair (frame-index,
+///                     transition-id) to a pair (sum-of-acoustic-scores,
+///                     num-of-occurences).
+///                     Usually the acoustic scores for a pdf-id (and hence
+///                     transition-id) on a frame will be the same for all the
+///                     occurences of the pdf-id in that frame. 
+///                     But if not, we will take the average of the acoustic
+///                     scores. Hence, we store both the sum-of-acoustic-scores
+///                     and the num-of-occurences of the transition-id in that
+///                     frame.
+void ComputeAcousticScoresMap(
+    const Lattice &lat,
+    unordered_map<std::pair<int32, int32>, std::pair<BaseFloat, int32>,
+                                        PairHasher<int32> > *acoustic_scores);
+
+/// This function restores acoustic scores computed using the function
+/// ComputeAcousticScoresMap into the lattice.
+///
+///   @param [in] acoustic_scores  
+///                      A map from the pair (frame-index, transition-id) to a
+///                      pair (sum-of-acoustic-scores, num-of-occurences) of 
+///                      the occurences of the transition-id in that frame.
+///                      See the comments for ComputeAcousticScoresMap for 
+///                      details.
+///   @param [out] lat   Pointer to the output lattice.
+void ReplaceAcousticScoresFromMap(
+    const unordered_map<std::pair<int32, int32>, std::pair<BaseFloat, int32>,
+                                        PairHasher<int32> > &acoustic_scores,
+    Lattice *lat);
+
+}  // namespace kaldi
+
+#endif  // KALDI_LAT_LATTICE_FUNCTIONS_H_

speechx/speechx/nnet/CMakeLists.txt

@@ -0,0 +1,2 @@
+aux_source_directory(. DIR_LIB_SRCS)
+add_library(nnet STATIC ${DIR_LIB_SRCS})

speechx/speechx/nnet/decodable-itf.h

@@ -0,0 +1,124 @@
+// itf/decodable-itf.h
+
+// Copyright 2009-2011  Microsoft Corporation;  Saarland University;
+//                      Mirko Hannemann;  Go Vivace Inc.;
+//                2013  Johns Hopkins University (author: Daniel Povey)
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef KALDI_ITF_DECODABLE_ITF_H_
+#define KALDI_ITF_DECODABLE_ITF_H_ 1
+#include "base/kaldi-common.h"
+
+namespace kaldi {
+/// @ingroup Interfaces
+/// @{
+
+
+/**
+    DecodableInterface provides a link between the (acoustic-modeling and
+    feature-processing) code and the decoder.  The idea is to make this
+    interface as small as possible, and to make it as agnostic as possible about
+    the form of the acoustic model (e.g. don't assume the probabilities are a
+    function of just a vector of floats), and about the decoder (e.g. don't
+    assume it accesses frames in strict left-to-right order).  For normal
+    models, without on-line operation, the "decodable" sub-class will just be a
+    wrapper around a matrix of features and an acoustic model, and it will
+    answer the question 'what is the acoustic likelihood for this index and this
+    frame?'.
+
+    For online decoding, where the features are coming in in real time, it is
+    important to understand the IsLastFrame() and NumFramesReady() functions.
+    There are two ways these are used: the old online-decoding code, in ../online/,
+    and the new online-decoding code, in ../online2/.  In the old online-decoding
+    code, the decoder would do:
+    \code{.cc}
+    for (int frame = 0; !decodable.IsLastFrame(frame); frame++) {
+      // Process this frame
+    }
+    \endcode
+   and the call to IsLastFrame would block if the features had not arrived yet.
+   The decodable object would have to know when to terminate the decoding.  This
+   online-decoding mode is still supported, it is what happens when you call, for
+   example, LatticeFasterDecoder::Decode().
+
+   We realized that this "blocking" mode of decoding is not very convenient
+   because it forces the program to be multi-threaded and makes it complex to
+   control endpointing.  In the "new" decoding code, you don't call (for example)
+   LatticeFasterDecoder::Decode(), you call LatticeFasterDecoder::InitDecoding(),
+   and then each time you get more features, you provide them to the decodable
+   object, and you call LatticeFasterDecoder::AdvanceDecoding(), which does
+   something like this:
+   \code{.cc}
+   while (num_frames_decoded_ < decodable.NumFramesReady()) {
+     // Decode one more frame [increments num_frames_decoded_]
+   }
+   \endcode
+   So the decodable object never has IsLastFrame() called.  For decoding where
+   you are starting with a matrix of features, the NumFramesReady() function will
+   always just return the number of frames in the file, and IsLastFrame() will
+   return true for the last frame.
+
+   For truly online decoding, the "old" online decodable objects in ../online/
+   have a "blocking" IsLastFrame() and will crash if you call NumFramesReady().
+   The "new" online decodable objects in ../online2/ return the number of frames
+   currently accessible if you call NumFramesReady().  You will likely not need
+   to call IsLastFrame(), but we implement it to only return true for the last
+   frame of the file once we've decided to terminate decoding.
+*/
+class DecodableInterface {
+ public:
+  /// Returns the log likelihood, which will be negated in the decoder.
+  /// The "frame" starts from zero.  You should verify that NumFramesReady() > frame
+  /// before calling this.
+  virtual BaseFloat LogLikelihood(int32 frame, int32 index) = 0;
+
+  /// Returns true if this is the last frame.  Frames are zero-based, so the
+  /// first frame is zero.  IsLastFrame(-1) will return false, unless the file
+  /// is empty (which is a case that I'm not sure all the code will handle, so
+  /// be careful).  Caution: the behavior of this function in an online setting
+  /// is being changed somewhat.  In future it may return false in cases where
+  /// we haven't yet decided to terminate decoding, but later true if we decide
+  /// to terminate decoding.  The plan in future is to rely more on
+  /// NumFramesReady(), and in future, IsLastFrame() would always return false
+  /// in an online-decoding setting, and would only return true in a
+  /// decoding-from-matrix setting where we want to allow the last delta or LDA
+  /// features to be flushed out for compatibility with the baseline setup.
+  virtual bool IsLastFrame(int32 frame) const = 0;
+
+  /// The call NumFramesReady() will return the number of frames currently available
+  /// for this decodable object.  This is for use in setups where you don't want the
+  /// decoder to block while waiting for input.  This is newly added as of Jan 2014,
+  /// and I hope, going forward, to rely on this mechanism more than IsLastFrame to
+  /// know when to stop decoding.
+  virtual int32 NumFramesReady() const {
+    KALDI_ERR << "NumFramesReady() not implemented for this decodable type.";
+    return -1;
+  }
+
+  /// Returns the number of states in the acoustic model
+  /// (they will be indexed one-based, i.e. from 1 to NumIndices();
+  /// this is for compatibility with OpenFst).
+  virtual int32 NumIndices() const = 0;
+
+  virtual std::vector<BaseFloat> FrameLogLikelihood(int32 frame);
+
+  virtual ~DecodableInterface() {}
+};
+/// @}
+}  // namespace Kaldi
+
+#endif  // KALDI_ITF_DECODABLE_ITF_H_

speechx/speechx/nnet/decodable.cc

@@ -0,0 +1,46 @@
+#include "nnet/decodable.h"
+
+namespace ppspeech {
+
+using kaldi::BaseFloat;
+using kaldi::Matrix;
+
+Decodable::Decodable(const std::shared_ptr<NnetInterface>& nnet):
+  frontend_(NULL),
+  nnet_(nnet),
+  finished_(false),
+  frames_ready_(0) {
+}
+
+void Decodable::Acceptlikelihood(const Matrix<BaseFloat>& likelihood) {
+  frames_ready_ += likelihood.NumRows();
+}
+
+//Decodable::Init(DecodableConfig config) {
+//}
+
+bool Decodable::IsLastFrame(int32 frame) const {
+  CHECK_LE(frame, frames_ready_);
+  return finished_ && (frame == frames_ready_ - 1);
+}
+
+int32 Decodable::NumIndices() const {
+  return 0;
+}
+
+BaseFloat Decodable::LogLikelihood(int32 frame, int32 index) {
+  return 0;
+}
+
+void Decodable::FeedFeatures(const Matrix<kaldi::BaseFloat>& features) {
+  nnet_->FeedForward(features, &nnet_cache_); 
+  frames_ready_ += nnet_cache_.NumRows(); 
+  return ;
+}
+
+void Decodable::Reset() {
+  // frontend_.Reset();
+  nnet_->Reset();
+}
+
+} // namespace ppspeech

speechx/speechx/nnet/decodable.h

@@ -0,0 +1,31 @@
+#include "nnet/decodable-itf.h"
+#include "base/common.h"
+#include "kaldi/matrix/kaldi-matrix.h"
+#include "frontend/feature_extractor_interface.h"
+#include "nnet/nnet_interface.h"
+
+namespace ppspeech {
+
+struct DecodableOpts;
+
+class Decodable : public kaldi::DecodableInterface {
+  public: 
+    explicit Decodable(const std::shared_ptr<NnetInterface>& nnet);
+    //void Init(DecodableOpts config);
+    virtual kaldi::BaseFloat LogLikelihood(int32 frame, int32 index);
+    virtual bool IsLastFrame(int32 frame) const;
+    virtual int32 NumIndices() const;
+    void Acceptlikelihood(const kaldi::Matrix<kaldi::BaseFloat>& likelihood); // remove later
+    void FeedFeatures(const kaldi::Matrix<kaldi::BaseFloat>& feature); // only for test, todo remove later
+    std::vector<BaseFloat> FrameLogLikelihood(int32 frame);
+    void Reset();
+    void InputFinished() { finished_ = true; }
+  private:
+    std::shared_ptr<FeatureExtractorInterface> frontend_;
+    std::shared_ptr<NnetInterface> nnet_;
+    kaldi::Matrix<kaldi::BaseFloat> nnet_cache_;
+    bool finished_;
+    int32 frames_ready_;
+};
+
+}  // namespace ppspeech

speechx/speechx/nnet/nnet_interface.h

@@ -0,0 +1,19 @@
+
+#pragma once
+
+#include "base/basic_types.h"
+#include "kaldi/base/kaldi-types.h"
+#include "kaldi/matrix/kaldi-matrix.h"
+
+namespace ppspeech {
+
+class NnetInterface {
+  public:
+    virtual ~NnetInterface() {}
+    virtual void FeedForward(const kaldi::Matrix<kaldi::BaseFloat>& features,
+                             kaldi::Matrix<kaldi::BaseFloat>* inferences); 
+    virtual void Reset();
+
+};
+
+}  // namespace ppspeech

speechx/speechx/nnet/paddle_nnet.cc

@@ -0,0 +1,182 @@
+#include "nnet/paddle_nnet.h"
+#include "absl/strings/str_split.h"
+
+namespace ppspeech {
+
+using std::vector;
+using std::string;
+using std::shared_ptr;
+using kaldi::Matrix;
+
+void PaddleNnet::InitCacheEncouts(const ModelOptions& opts) {
+  std::vector<std::string> cache_names;
+  cache_names = absl::StrSplit(opts.cache_names, ", ");
+  std::vector<std::string> cache_shapes;
+  cache_shapes = absl::StrSplit(opts.cache_shape, ", ");
+  assert(cache_shapes.size() == cache_names.size());
+
+  for (size_t i = 0; i < cache_shapes.size(); i++) {
+    std::vector<std::string> tmp_shape;
+    tmp_shape = absl::StrSplit(cache_shapes[i], "- ");
+    std::vector<int> cur_shape;
+    std::transform(tmp_shape.begin(), tmp_shape.end(),
+                    std::back_inserter(cur_shape),
+                    [](const std::string& s) {
+                        return atoi(s.c_str());
+                    });
+    cache_names_idx_[cache_names[i]] = i;
+    std::shared_ptr<Tensor<BaseFloat>> cache_eout = std::make_shared<Tensor<BaseFloat>>(cur_shape);
+    cache_encouts_.push_back(cache_eout);
+  }
+}
+
+PaddleNnet::PaddleNnet(const ModelOptions& opts) {
+    paddle_infer::Config config;
+    config.SetModel(opts.model_path, opts.params_path);
+    if (opts.use_gpu) {
+      config.EnableUseGpu(500, 0);
+    }
+    config.SwitchIrOptim(opts.switch_ir_optim);
+    if (opts.enable_fc_padding) {
+      config.DisableFCPadding();
+    }
+    if (opts.enable_profile) {
+      config.EnableProfile();
+    }
+    pool.reset(new paddle_infer::services::PredictorPool(config, opts.thread_num));
+    if (pool == nullptr) {
+        LOG(ERROR) << "create the predictor pool failed";
+    }
+    pool_usages.resize(opts.thread_num);
+    std::fill(pool_usages.begin(), pool_usages.end(), false);
+    LOG(INFO) << "load paddle model success";
+
+    LOG(INFO) << "start to check the predictor input and output names";
+    LOG(INFO) << "input names: " << opts.input_names;
+    LOG(INFO) << "output names: " << opts.output_names;
+    vector<string> input_names_vec = absl::StrSplit(opts.input_names, ", ");
+    vector<string> output_names_vec = absl::StrSplit(opts.output_names, ", ");
+    paddle_infer::Predictor* predictor = GetPredictor();
+        
+    std::vector<std::string> model_input_names = predictor->GetInputNames();
+    assert(input_names_vec.size() == model_input_names.size());
+    for (size_t i = 0; i < model_input_names.size(); i++) {
+        assert(input_names_vec[i] == model_input_names[i]);
+    }
+
+    std::vector<std::string> model_output_names = predictor->GetOutputNames();
+    assert(output_names_vec.size() == model_output_names.size());
+    for (size_t i = 0;i < output_names_vec.size(); i++) {
+        assert(output_names_vec[i] == model_output_names[i]);
+    }
+    ReleasePredictor(predictor);
+
+    InitCacheEncouts(opts);
+}
+
+paddle_infer::Predictor* PaddleNnet::GetPredictor() {
+    LOG(INFO) << "attempt to get a new predictor instance " << std::endl;
+    paddle_infer::Predictor* predictor = nullptr;
+    std::lock_guard<std::mutex> guard(pool_mutex);
+    int pred_id = 0;
+
+    while (pred_id < pool_usages.size()) {
+        if (pool_usages[pred_id] == false) {
+            predictor = pool->Retrive(pred_id);
+            break;
+        }
+        ++pred_id;
+    }
+
+    if (predictor) {
+        pool_usages[pred_id] = true;
+        predictor_to_thread_id[predictor] = pred_id;
+        LOG(INFO) << pred_id << " predictor create success";
+    } else {
+        LOG(INFO) << "Failed to get predictor from pool !!!";
+    }
+
+    return predictor;
+}
+
+int PaddleNnet::ReleasePredictor(paddle_infer::Predictor* predictor) {
+    LOG(INFO) << "attempt to releae a predictor";
+    std::lock_guard<std::mutex> guard(pool_mutex);
+    auto iter = predictor_to_thread_id.find(predictor);
+
+    if (iter == predictor_to_thread_id.end()) {
+        LOG(INFO) << "there is no such predictor";
+        return 0;
+    }
+
+    LOG(INFO) << iter->second << " predictor will be release";
+    pool_usages[iter->second] = false;
+    predictor_to_thread_id.erase(predictor);
+    LOG(INFO) << "release success";
+    return 0;
+}
+
+shared_ptr<Tensor<BaseFloat>> PaddleNnet::GetCacheEncoder(const string& name) {
+  auto iter = cache_names_idx_.find(name);
+  if (iter == cache_names_idx_.end()) {
+    return nullptr;
+  }
+  assert(iter->second < cache_encouts_.size());
+  return cache_encouts_[iter->second]; 
+}
+
+void PaddleNnet::FeedForward(const Matrix<BaseFloat>& features, Matrix<BaseFloat>* inferences) {
+    
+    paddle_infer::Predictor* predictor = GetPredictor(); 
+    // 1. 得到所有的 input tensor 的名称
+    int row = features.NumRows();
+    int col = features.NumCols();
+    std::vector<std::string> input_names = predictor->GetInputNames();
+    std::vector<std::string> output_names = predictor->GetOutputNames();
+    LOG(INFO) << "feat info: row=" << row << ", col=" << col;
+
+    std::unique_ptr<paddle_infer::Tensor> input_tensor = predictor->GetInputHandle(input_names[0]);
+    std::vector<int> INPUT_SHAPE = {1, row, col};
+    input_tensor->Reshape(INPUT_SHAPE);
+    input_tensor->CopyFromCpu(features.Data());
+    // 3. 输入每个音频帧数
+    std::unique_ptr<paddle_infer::Tensor> input_len = predictor->GetInputHandle(input_names[1]);
+    std::vector<int> input_len_size = {1};
+    input_len->Reshape(input_len_size);
+    std::vector<int64_t> audio_len;
+    audio_len.push_back(row);
+    input_len->CopyFromCpu(audio_len.data());
+    // 输入流式的缓存数据
+    std::unique_ptr<paddle_infer::Tensor> h_box = predictor->GetInputHandle(input_names[2]);
+    shared_ptr<Tensor<BaseFloat>> h_cache = GetCacheEncoder(input_names[2]);
+    h_box->Reshape(h_cache->get_shape());
+    h_box->CopyFromCpu(h_cache->get_data().data());
+    std::unique_ptr<paddle_infer::Tensor> c_box = predictor->GetInputHandle(input_names[3]);
+    shared_ptr<Tensor<float>> c_cache = GetCacheEncoder(input_names[3]);
+    c_box->Reshape(c_cache->get_shape());
+    c_box->CopyFromCpu(c_cache->get_data().data());
+    bool success = predictor->Run();
+
+    if (success == false) {
+        LOG(INFO) << "predictor run occurs error";
+    }
+
+    LOG(INFO) << "get the model success";
+    std::unique_ptr<paddle_infer::Tensor> h_out = predictor->GetOutputHandle(output_names[2]);
+    assert(h_cache->get_shape() == h_out->shape());
+    h_out->CopyToCpu(h_cache->get_data().data());
+    std::unique_ptr<paddle_infer::Tensor> c_out = predictor->GetOutputHandle(output_names[3]);
+    assert(c_cache->get_shape() == c_out->shape());
+    c_out->CopyToCpu(c_cache->get_data().data());
+    // 5. 得到最后的输出结果
+    std::unique_ptr<paddle_infer::Tensor> output_tensor =
+        predictor->GetOutputHandle(output_names[0]);
+    std::vector<int> output_shape = output_tensor->shape();
+    row = output_shape[1];
+    col = output_shape[2];
+    inferences->Resize(row, col);
+    output_tensor->CopyToCpu(inferences->Data());
+    ReleasePredictor(predictor);
+}
+
+} // namespace ppspeech           

speechx/speechx/nnet/paddle_nnet.h

@@ -0,0 +1,108 @@
+
+#pragma once
+
+#include "nnet/nnet_interface.h"
+#include "base/common.h"
+#include "paddle_inference_api.h"
+
+#include "kaldi/matrix/kaldi-matrix.h"
+#include "kaldi/util/options-itf.h"
+
+#include <numeric>
+
+namespace ppspeech {
+
+struct ModelOptions {
+  std::string model_path;
+  std::string params_path;
+  int thread_num;
+  bool use_gpu;
+  bool switch_ir_optim;
+  std::string input_names;
+  std::string output_names;
+  std::string cache_names;
+  std::string cache_shape;
+  bool enable_fc_padding;
+  bool enable_profile;
+  ModelOptions() : 
+      model_path("model/final.zip"),
+      params_path("model/avg_1.jit.pdmodel"),
+      thread_num(2),
+      use_gpu(false),
+      input_names("audio"),
+      output_names("probs"),
+      cache_names("enouts"),
+      cache_shape("1-1-1"),
+      switch_ir_optim(false),
+      enable_fc_padding(false),
+      enable_profile(false) {
+  }
+
+  void Register(kaldi::OptionsItf* opts) {
+    opts->Register("model-path", &model_path, "model file path");
+    opts->Register("model-params", &params_path, "params model file path");
+    opts->Register("thread-num", &thread_num, "thread num");
+    opts->Register("use-gpu", &use_gpu, "if use gpu");
+    opts->Register("input-names", &input_names, "paddle input names");
+    opts->Register("output-names", &output_names, "paddle output names");
+    opts->Register("cache-names", &cache_names, "cache names");
+    opts->Register("cache-shape", &cache_shape, "cache shape");
+    opts->Register("switch-ir-optiom", &switch_ir_optim, "paddle SwitchIrOptim option");
+    opts->Register("enable-fc-padding", &enable_fc_padding, "paddle EnableFCPadding option");
+    opts->Register("enable-profile", &enable_profile, "paddle EnableProfile option");
+  }
+};
+
+template<typename T>
+class Tensor {
+public:
+    Tensor() {
+    }
+    Tensor(const std::vector<int>& shape) :
+        _shape(shape) {
+        int data_size = std::accumulate(_shape.begin(), _shape.end(),
+                                            1, std::multiplies<int>());
+        LOG(INFO) << "data size: " << data_size;
+        _data.resize(data_size, 0);
+    }
+    void reshape(const std::vector<int>& shape) {
+        _shape = shape;
+        int data_size = std::accumulate(_shape.begin(), _shape.end(),
+                                        1, std::multiplies<int>());
+        _data.resize(data_size, 0);
+    }
+    const std::vector<int>& get_shape() const {
+        return _shape;
+    }
+    std::vector<T>& get_data() {
+        return _data;
+    }
+private:
+    std::vector<int> _shape;
+    std::vector<T> _data;
+};
+
+class PaddleNnet : public NnetInterface {
+  public:
+    PaddleNnet(const ModelOptions& opts);
+    virtual void FeedForward(const kaldi::Matrix<kaldi::BaseFloat>& features, 
+                             kaldi::Matrix<kaldi::BaseFloat>* inferences);
+    std::shared_ptr<Tensor<kaldi::BaseFloat>> GetCacheEncoder(const std::string& name);
+    void InitCacheEncouts(const ModelOptions& opts);
+    
+  private:
+    paddle_infer::Predictor* GetPredictor();
+    int ReleasePredictor(paddle_infer::Predictor* predictor); 
+
+    std::unique_ptr<paddle_infer::services::PredictorPool> pool;
+    std::vector<bool> pool_usages;
+    std::mutex pool_mutex;
+    std::map<paddle_infer::Predictor*, int> predictor_to_thread_id;
+    std::map<std::string, int> cache_names_idx_;
+    std::vector<std::shared_ptr<Tensor<kaldi::BaseFloat>>> cache_encouts_;
+
+  public:
+    DISALLOW_COPY_AND_ASSIGN(PaddleNnet);
+};
+
+} // namespace ppspeech                                                                                                                                                                                                                             

speechx/speechx/utils/CMakeLists.txt

@@ -0,0 +1,4 @@
+
+add_library(utils
+  file_utils.cc
+)

speechx/speechx/utils/file_utils.cc

@@ -0,0 +1,17 @@
+#include "utils/file_utils.h"
+
+bool ReadFileToVector(const std::string& filename,
+                      std::vector<std::string>* vocabulary) {
+    std::ifstream file_in(filename);
+    if (!file_in) {
+        std::cerr << "please input a valid file" << std::endl;
+        return false;
+    }
+
+    std::string line;
+    while (std::getline(file_in, line)) {
+        vocabulary->emplace_back(line);
+    }
+
+    return true;
+}

speechx/speechx/utils/file_utils.h

@@ -0,0 +1,8 @@
+#include "base/common.h"
+
+namespace ppspeech {
+
+bool ReadFileToVector(const std::string& filename, 
+                      std::vector<std::string>* data); 
+
+}