blob: 8bfaec5d3f9a2f7f925a9c3acc7686a92ab36b8f [file] [log] [blame]
pbos@webrtc.org788acd12014-12-15 09:41:24 +00001/*
2 * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
Mirko Bonadei92ea95e2017-09-15 06:47:31 +020011#include "modules/audio_processing/vad/gmm.h"
pbos@webrtc.org788acd12014-12-15 09:41:24 +000012
13#include <math.h>
14#include <stdlib.h>
15
Mirko Bonadei92ea95e2017-09-15 06:47:31 +020016#include "typedefs.h"
pbos@webrtc.org788acd12014-12-15 09:41:24 +000017
18namespace webrtc {
19
20static const int kMaxDimension = 10;
21
aluebsecf6b812015-06-25 12:28:48 -070022static void RemoveMean(const double* in,
23 const double* mean_vec,
24 int dimension,
25 double* out) {
pbos@webrtc.org788acd12014-12-15 09:41:24 +000026 for (int n = 0; n < dimension; ++n)
27 out[n] = in[n] - mean_vec[n];
28}
29
aluebsecf6b812015-06-25 12:28:48 -070030static double ComputeExponent(const double* in,
31 const double* covar_inv,
pbos@webrtc.org788acd12014-12-15 09:41:24 +000032 int dimension) {
33 double q = 0;
34 for (int i = 0; i < dimension; ++i) {
35 double v = 0;
36 for (int j = 0; j < dimension; j++)
37 v += (*covar_inv++) * in[j];
38 q += v * in[i];
39 }
40 q *= -0.5;
41 return q;
42}
43
44double EvaluateGmm(const double* x, const GmmParameters& gmm_parameters) {
45 if (gmm_parameters.dimension > kMaxDimension) {
46 return -1; // This is invalid pdf so the caller can check this.
47 }
48 double f = 0;
49 double v[kMaxDimension];
50 const double* mean_vec = gmm_parameters.mean;
51 const double* covar_inv = gmm_parameters.covar_inverse;
52
53 for (int n = 0; n < gmm_parameters.num_mixtures; n++) {
54 RemoveMean(x, mean_vec, gmm_parameters.dimension, v);
55 double q = ComputeExponent(v, covar_inv, gmm_parameters.dimension) +
aluebsecf6b812015-06-25 12:28:48 -070056 gmm_parameters.weight[n];
pbos@webrtc.org788acd12014-12-15 09:41:24 +000057 f += exp(q);
58 mean_vec += gmm_parameters.dimension;
59 covar_inv += gmm_parameters.dimension * gmm_parameters.dimension;
60 }
61 return f;
62}
63
64} // namespace webrtc