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1 /* | |
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 | |
11 #include "webrtc/modules/audio_processing/agc/gmm.h" | |
12 | |
13 #include <math.h> | |
14 #include <stdlib.h> | |
15 | |
16 #include "webrtc/typedefs.h" | |
17 | |
18 namespace webrtc { | |
19 | |
20 static const int kMaxDimension = 10; | |
21 | |
22 static void RemoveMean(const double* in, const double* mean_vec, | |
23 int dimension, double* out) { | |
24 for (int n = 0; n < dimension; ++n) | |
25 out[n] = in[n] - mean_vec[n]; | |
26 } | |
27 | |
28 static double ComputeExponent(const double* in, const double* covar_inv, | |
29 int dimension) { | |
30 double q = 0; | |
31 for (int i = 0; i < dimension; ++i) { | |
32 double v = 0; | |
33 for (int j = 0; j < dimension; j++) | |
34 v += (*covar_inv++) * in[j]; | |
35 q += v * in[i]; | |
36 } | |
37 q *= -0.5; | |
38 return q; | |
39 } | |
40 | |
41 double EvaluateGmm(const double* x, const GmmParameters& gmm_parameters) { | |
42 if (gmm_parameters.dimension > kMaxDimension) { | |
43 return -1; // This is invalid pdf so the caller can check this. | |
44 } | |
45 double f = 0; | |
46 double v[kMaxDimension]; | |
47 const double* mean_vec = gmm_parameters.mean; | |
48 const double* covar_inv = gmm_parameters.covar_inverse; | |
49 | |
50 for (int n = 0; n < gmm_parameters.num_mixtures; n++) { | |
51 RemoveMean(x, mean_vec, gmm_parameters.dimension, v); | |
52 double q = ComputeExponent(v, covar_inv, gmm_parameters.dimension) + | |
53 gmm_parameters.weight[n]; | |
54 f += exp(q); | |
55 mean_vec += gmm_parameters.dimension; | |
56 covar_inv += gmm_parameters.dimension * gmm_parameters.dimension; | |
57 } | |
58 return f; | |
59 } | |
60 | |
61 } // namespace webrtc | |
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