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PaddleSpeech/runtime/engine/common/utils/math.cc

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// Copyright (c) 2021 Mobvoi Inc (Zhendong Peng)
// 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 "utils/math.h"
#include "base/basic_types.h"
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <utility>
#include <vector>
namespace ppspeech {
// Sum in log scale
float LogSumExp(float x, float y) {
if (x <= -kBaseFloatMax) return y;
if (y <= -kBaseFloatMax) return x;
float max = std::max(x, y);
return max + std::log(std::exp(x - max) + std::exp(y - max));
}
// greater compare for smallest priority_queue
template <typename T>
struct ValGreaterComp {
bool operator()(const std::pair<T, int32_t>& lhs,
const std::pair<T, int32_t>& rhs) const {
return lhs.first > rhs.first ||
(lhs.first == rhs.first && lhs.second < rhs.second);
}
};
template <typename T>
void TopK(const std::vector<T>& data,
int32_t k,
std::vector<T>* values,
std::vector<int>* indices) {
int n = data.size();
int min_k_n = std::min(k, n);
// smallest heap, (val, idx)
std::vector<std::pair<T, int32_t>> smallest_heap;
for (int i = 0; i < min_k_n; i++) {
smallest_heap.emplace_back(data[i], i);
}
// smallest priority_queue
std::priority_queue<std::pair<T, int32_t>,
std::vector<std::pair<T, int32_t>>,
ValGreaterComp<T>>
pq(ValGreaterComp<T>(), std::move(smallest_heap));
// top k
for (int i = k; i < n; i++) {
if (pq.top().first < data[i]) {
pq.pop();
pq.emplace(data[i], i);
}
}
values->resize(min_k_n);
indices->resize(min_k_n);
// from largest to samllest
int cur = values->size() - 1;
while (!pq.empty()) {
const auto& item = pq.top();
(*values)[cur] = item.first;
(*indices)[cur] = item.second;
// item if reference, must pop here
pq.pop();
cur--;
}
}
template void TopK<float>(const std::vector<float>& data,
int32_t k,
std::vector<float>* values,
std::vector<int>* indices);
} // namespace ppspeech