1 | /* |
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2 | Copyright (C) 2007 Amaury Hazan <ahazan@iua.upf.edu> |
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3 | and Paul Brossier <piem@piem.org> |
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4 | |
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5 | This program is free software; you can redistribute it and/or modify |
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6 | it under the terms of the GNU General Public License as published by |
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7 | the Free Software Foundation; either version 2 of the License, or |
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8 | (at your option) any later version. |
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9 | |
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10 | This program is distributed in the hope that it will be useful, |
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11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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13 | GNU General Public License for more details. |
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14 | |
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15 | You should have received a copy of the GNU General Public License |
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16 | along with this program; if not, write to the Free Software |
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17 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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18 | |
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19 | */ |
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20 | |
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21 | /* part of this mfcc implementation were inspired from LibXtract |
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22 | http://libxtract.sourceforge.net/ |
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23 | */ |
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24 | |
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25 | #include "aubio_priv.h" |
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26 | #include "sample.h" |
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27 | #include "filterbank.h" |
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28 | |
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29 | #define USE_EQUAL_GAIN 1 |
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30 | #define VERY_SMALL_NUMBER 2e-42 |
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31 | |
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32 | /** \brief A structure to store a set of n_filters filters of lenghts win_s */ |
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33 | struct aubio_filterbank_t_ { |
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34 | uint_t win_s; |
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35 | uint_t n_filters; |
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36 | fvec_t **filters; |
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37 | }; |
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38 | |
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39 | aubio_filterbank_t * new_aubio_filterbank(uint_t n_filters, uint_t win_s){ |
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40 | /** allocating space for filterbank object */ |
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41 | aubio_filterbank_t * fb = AUBIO_NEW(aubio_filterbank_t); |
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42 | uint_t filter_cnt; |
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43 | fb->win_s=win_s; |
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44 | fb->n_filters=n_filters; |
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45 | |
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46 | /** allocating filter tables */ |
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47 | fb->filters=AUBIO_ARRAY(fvec_t*,n_filters); |
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48 | for (filter_cnt=0; filter_cnt<n_filters; filter_cnt++) |
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49 | /* considering one-channel filters */ |
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50 | fb->filters[filter_cnt]=new_fvec(win_s, 1); |
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51 | |
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52 | return fb; |
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53 | } |
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54 | |
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55 | aubio_filterbank_t * new_aubio_filterbank_mfcc(uint_t n_filters, uint_t win_s, smpl_t samplerate, smpl_t freq_min, smpl_t freq_max){ |
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56 | smpl_t nyquist = samplerate/2.; |
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57 | uint_t style = 1; |
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58 | aubio_filterbank_t * fb = new_aubio_filterbank(n_filters, win_s); |
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59 | |
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60 | uint_t n, i, k, *fft_peak, M, next_peak; |
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61 | smpl_t norm, mel_freq_max, mel_freq_min, norm_fact, height, inc, val, |
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62 | freq_bw_mel, *mel_peak, *height_norm, *lin_peak; |
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63 | |
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64 | mel_peak = height_norm = lin_peak = NULL; |
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65 | fft_peak = NULL; |
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66 | norm = 1; |
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67 | |
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68 | mel_freq_max = 1127 * log(1 + freq_max / 700); |
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69 | mel_freq_min = 1127 * log(1 + freq_min / 700); |
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70 | freq_bw_mel = (mel_freq_max - mel_freq_min) / fb->n_filters; |
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71 | |
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72 | mel_peak = (smpl_t *)malloc((fb->n_filters + 2) * sizeof(smpl_t)); |
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73 | /* +2 for zeros at start and end */ |
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74 | lin_peak = (smpl_t *)malloc((fb->n_filters + 2) * sizeof(smpl_t)); |
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75 | fft_peak = (uint_t *)malloc((fb->n_filters + 2) * sizeof(uint_t)); |
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76 | height_norm = (smpl_t *)malloc(fb->n_filters * sizeof(smpl_t)); |
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77 | |
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78 | if(mel_peak == NULL || height_norm == NULL || |
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79 | lin_peak == NULL || fft_peak == NULL) |
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80 | return NULL; |
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81 | |
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82 | M = fb->win_s >> 1; |
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83 | |
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84 | mel_peak[0] = mel_freq_min; |
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85 | lin_peak[0] = 700 * (exp(mel_peak[0] / 1127) - 1); |
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86 | fft_peak[0] = lin_peak[0] / nyquist * M; |
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87 | |
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88 | |
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89 | for (n = 1; n <= fb->n_filters; n++){ |
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90 | /*roll out peak locations - mel, linear and linear on fft window scale */ |
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91 | mel_peak[n] = mel_peak[n - 1] + freq_bw_mel; |
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92 | lin_peak[n] = 700 * (exp(mel_peak[n] / 1127) -1); |
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93 | fft_peak[n] = lin_peak[n] / nyquist * M; |
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94 | } |
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95 | |
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96 | for (n = 0; n < fb->n_filters; n++){ |
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97 | /*roll out normalised gain of each peak*/ |
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98 | if (style == USE_EQUAL_GAIN){ |
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99 | height = 1; |
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100 | norm_fact = norm; |
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101 | } |
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102 | else{ |
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103 | height = 2 / (lin_peak[n + 2] - lin_peak[n]); |
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104 | norm_fact = norm / (2 / (lin_peak[2] - lin_peak[0])); |
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105 | } |
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106 | height_norm[n] = height * norm_fact; |
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107 | } |
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108 | |
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109 | i = 0; |
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110 | |
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111 | for(n = 0; n < fb->n_filters; n++){ |
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112 | |
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113 | /*calculate the rise increment*/ |
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114 | if(n > 0) |
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115 | inc = height_norm[n] / (fft_peak[n] - fft_peak[n - 1]); |
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116 | else |
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117 | inc = height_norm[n] / fft_peak[n]; |
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118 | val = 0; |
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119 | |
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120 | /*zero the start of the array*/ |
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121 | for(k = 0; k < i; k++) |
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122 | //fft_tables[n][k] = 0.f; |
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123 | fb->filters[n]->data[0][k]=0.f; |
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124 | |
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125 | /*fill in the rise */ |
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126 | for(; i <= fft_peak[n]; i++){ |
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127 | // fft_tables[n][i] = val; |
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128 | fb->filters[n]->data[0][k]=val; |
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129 | val += inc; |
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130 | } |
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131 | |
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132 | /*calculate the fall increment */ |
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133 | inc = height_norm[n] / (fft_peak[n + 1] - fft_peak[n]); |
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134 | |
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135 | val = 0; |
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136 | next_peak = fft_peak[n + 1]; |
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137 | |
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138 | /*reverse fill the 'fall' */ |
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139 | for(i = next_peak; i > fft_peak[n]; i--){ |
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140 | //fft_tables[n][i] = val; |
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141 | fb->filters[n]->data[0][k]=val; |
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142 | val += inc; |
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143 | } |
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144 | |
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145 | /*zero the rest of the array*/ |
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146 | for(k = next_peak + 1; k < fb->win_s; k++) |
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147 | //fft_tables[n][k] = 0.f; |
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148 | fb->filters[n]->data[0][k]=0.f; |
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149 | } |
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150 | |
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151 | free(mel_peak); |
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152 | free(lin_peak); |
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153 | free(height_norm); |
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154 | free(fft_peak); |
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155 | |
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156 | return fb; |
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157 | |
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158 | } |
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159 | |
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160 | |
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161 | void del_aubio_filterbank(aubio_filterbank_t * fb){ |
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162 | uint_t filter_cnt; |
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163 | /** deleting filter tables first */ |
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164 | for (filter_cnt=0; filter_cnt<fb->n_filters; filter_cnt++) |
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165 | del_fvec(fb->filters[filter_cnt]); |
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166 | AUBIO_FREE(fb->filters); |
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167 | AUBIO_FREE(fb); |
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168 | } |
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169 | |
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170 | void aubio_filterbank_do(aubio_filterbank_t * f, cvec_t * in, fvec_t *out) { |
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171 | uint_t n, filter_cnt; |
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172 | for(filter_cnt = 0; (filter_cnt < f->n_filters) |
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173 | && (filter_cnt < out->length); filter_cnt++){ |
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174 | out->data[0][filter_cnt] = 0.f; |
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175 | for(n = 0; n < in->length; n++){ |
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176 | out->data[0][filter_cnt] += in->norm[0][n] |
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177 | * f->filters[filter_cnt]->data[0][n]; |
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178 | } |
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179 | out->data[0][filter_cnt] = |
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180 | LOG(out->data[0][filter_cnt] < VERY_SMALL_NUMBER ? |
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181 | VERY_SMALL_NUMBER : out->data[0][filter_cnt]); |
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182 | } |
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183 | |
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184 | return; |
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185 | } |
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