You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
57 lines
1.6 KiB
57 lines
1.6 KiB
/**
|
|
* Copyright (c) 2022 Xiaomi Corporation (authors: Fangjun Kuang)
|
|
*
|
|
* See LICENSE 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
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef KALDI_NATIVE_FBANK_CSRC_RFFT_H_
|
|
#define KALDI_NATIVE_FBANK_CSRC_RFFT_H_
|
|
|
|
#include <memory>
|
|
|
|
namespace knf {
|
|
|
|
// n-point Real discrete Fourier transform
|
|
// where n is a power of 2. n >= 2
|
|
//
|
|
// R[k] = sum_j=0^n-1 in[j]*cos(2*pi*j*k/n), 0<=k<=n/2
|
|
// I[k] = sum_j=0^n-1 in[j]*sin(2*pi*j*k/n), 0<k<n/2
|
|
class Rfft {
|
|
public:
|
|
// @param n Number of fft bins. it should be a power of 2.
|
|
explicit Rfft(int32_t n);
|
|
~Rfft();
|
|
|
|
/** @param in_out A 1-D array of size n.
|
|
* On return:
|
|
* in_out[0] = R[0]
|
|
* in_out[1] = R[n/2]
|
|
* for 1 < k < n/2,
|
|
* in_out[2*k] = R[k]
|
|
* in_out[2*k+1] = I[k]
|
|
*
|
|
*/
|
|
void Compute(float *in_out);
|
|
void Compute(double *in_out);
|
|
|
|
private:
|
|
class RfftImpl;
|
|
std::unique_ptr<RfftImpl> impl_;
|
|
};
|
|
|
|
} // namespace knf
|
|
|
|
#endif // KALDI_NATIVE_FBANK_CSRC_RFFT_H_
|