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| 1 | +#include <stdio.h> |
| 2 | +#include <stdlib.h> |
| 3 | +#include <math.h> |
| 4 | +#include "RBM.h" |
| 5 | + |
| 6 | +double uniform(double, double); |
| 7 | +int binomial(int, double); |
| 8 | +double sigmoid(double); |
| 9 | + |
| 10 | + |
| 11 | +void test_rbm(void); |
| 12 | + |
| 13 | + |
| 14 | +double uniform(double min, double max) { |
| 15 | + return rand() / (RAND_MAX + 1.0) * (max - min) + min; |
| 16 | +} |
| 17 | + |
| 18 | +int binomial(int n, double p) { |
| 19 | + if(p < 0 || p > 1) return 0; |
| 20 | + |
| 21 | + int i; |
| 22 | + int c = 0; |
| 23 | + double r; |
| 24 | + |
| 25 | + for(i=0; i<n; i++) { |
| 26 | + r = rand() / (RAND_MAX + 1.0); |
| 27 | + if (r < p) c++; |
| 28 | + } |
| 29 | + |
| 30 | + return c; |
| 31 | +} |
| 32 | + |
| 33 | +double sigmoid(double x) { |
| 34 | + return 1.0 / (1.0 + exp(-x)); |
| 35 | +} |
| 36 | + |
| 37 | + |
| 38 | +void RBM__construct(RBM* this, int N, int n_visible, int n_hidden) { |
| 39 | + int i, j; |
| 40 | + double a = 1.0 / n_visible; |
| 41 | + |
| 42 | + this->N = N; |
| 43 | + this->n_visible = n_visible; |
| 44 | + this->n_hidden = n_hidden; |
| 45 | + |
| 46 | + this->W = (double **)malloc(sizeof(double*) * n_hidden); |
| 47 | + this->W[0] = (double *)malloc(sizeof(double) * n_visible * n_hidden); |
| 48 | + for(i=0; i<n_hidden; i++) this->W[i] = this->W[0] + i * n_visible; |
| 49 | + this->hbias = (double *)malloc(sizeof(double) * n_hidden); |
| 50 | + this->vbias = (double *)malloc(sizeof(double) * n_visible); |
| 51 | + |
| 52 | + for(i=0; i<n_hidden; i++) { |
| 53 | + for(j=0; j<n_visible; j++) { |
| 54 | + this->W[i][j] = uniform(-a, a); |
| 55 | + } |
| 56 | + } |
| 57 | +} |
| 58 | + |
| 59 | +void RBM__destruct(RBM* this) { |
| 60 | + free(this->W); |
| 61 | + free(this->hbias); |
| 62 | + free(this->vbias); |
| 63 | +} |
| 64 | + |
| 65 | +void RBM_contrastive_divergence(RBM* this, int *input, double lr, int k) { |
| 66 | + int i, j, step; |
| 67 | + |
| 68 | + double *ph_mean = (double *)malloc(sizeof(double) * this->n_hidden); |
| 69 | + int *ph_sample = (int *)malloc(sizeof(int) * this->n_hidden); |
| 70 | + double *nv_means = (double *)malloc(sizeof(double) * this->n_visible); |
| 71 | + int *nv_samples = (int *)malloc(sizeof(int) * this->n_visible); |
| 72 | + double *nh_means = (double *)malloc(sizeof(double) * this->n_hidden); |
| 73 | + int *nh_samples = (int *)malloc(sizeof(int) * this->n_hidden); |
| 74 | + |
| 75 | + /* CD-k */ |
| 76 | + RBM_sample_h_given_v(this, input, ph_mean, ph_sample); |
| 77 | + |
| 78 | + for(step=0; step<k; step++) { |
| 79 | + if(step == 0) { |
| 80 | + RBM_gibbs_hvh(this, ph_sample, nv_means, nv_samples, nh_means, nh_samples); |
| 81 | + } else { |
| 82 | + RBM_gibbs_hvh(this, nh_samples, nv_means, nv_samples, nh_means, nh_samples); |
| 83 | + } |
| 84 | + } |
| 85 | + |
| 86 | + for(i=0; i<this->n_hidden; i++) { |
| 87 | + for(j=0; j<this->n_visible; j++) { |
| 88 | + this->W[i][j] += lr * (ph_sample[i] * input[j] - nh_means[i] * nv_samples[j]) / this->N; |
| 89 | + } |
| 90 | + this->hbias[i] += lr * (ph_sample[i] - nh_means[i]) / this->N; |
| 91 | + } |
| 92 | + |
| 93 | + for(i=0; i<this->n_visible; i++) { |
| 94 | + this->vbias[i] += lr * (input[i] - nv_samples[i]) / this->N; |
| 95 | + } |
| 96 | + |
| 97 | + |
| 98 | + free(ph_mean); |
| 99 | + free(ph_sample); |
| 100 | + free(nv_means); |
| 101 | + free(nv_samples); |
| 102 | + free(nh_means); |
| 103 | + free(nh_samples); |
| 104 | +} |
| 105 | + |
| 106 | + |
| 107 | +void RBM_sample_h_given_v(RBM* this, int *v0_sample, double *mean, int *sample) { |
| 108 | + int i; |
| 109 | + for(i=0; i<this->n_hidden; i++) { |
| 110 | + mean[i] = RBM_propup(this, v0_sample, this->W[i], this->hbias[i]); |
| 111 | + sample[i] = binomial(1, mean[i]); |
| 112 | + } |
| 113 | +} |
| 114 | + |
| 115 | +void RBM_sample_v_given_h(RBM* this, int *h0_sample, double *mean, int *sample) { |
| 116 | + int i; |
| 117 | + for(i=0; i<this->n_visible; i++) { |
| 118 | + mean[i] = RBM_propdown(this, h0_sample, i, this->vbias[i]); |
| 119 | + sample[i] = binomial(1, mean[i]); |
| 120 | + } |
| 121 | +} |
| 122 | + |
| 123 | +double RBM_propup(RBM* this, int *v, double *w, double b) { |
| 124 | + int j; |
| 125 | + double pre_sigmoid_activation = 0.0; |
| 126 | + for(j=0; j<this->n_visible; j++) { |
| 127 | + pre_sigmoid_activation += w[j] * v[j]; |
| 128 | + } |
| 129 | + pre_sigmoid_activation += b; |
| 130 | + return sigmoid(pre_sigmoid_activation); |
| 131 | +} |
| 132 | + |
| 133 | +double RBM_propdown(RBM* this, int *h, int i, double b) { |
| 134 | + int j; |
| 135 | + double pre_sigmoid_activation = 0.0; |
| 136 | + |
| 137 | + for(j=0; j<this->n_hidden; j++) { |
| 138 | + pre_sigmoid_activation += this->W[j][i] * h[j]; |
| 139 | + } |
| 140 | + pre_sigmoid_activation += b; |
| 141 | + return sigmoid(pre_sigmoid_activation); |
| 142 | +} |
| 143 | + |
| 144 | +void RBM_gibbs_hvh(RBM* this, int *h0_sample, double *nv_means, int *nv_samples, \ |
| 145 | + double *nh_means, int *nh_samples) { |
| 146 | + RBM_sample_v_given_h(this, h0_sample, nv_means, nv_samples); |
| 147 | + RBM_sample_h_given_v(this, nv_samples, nh_means, nh_samples); |
| 148 | +} |
| 149 | + |
| 150 | +void RBM_reconstruct(RBM* this, int *v, double *reconstructed_v) { |
| 151 | + int i, j; |
| 152 | + double *h = (double *)malloc(sizeof(double) * this->n_hidden); |
| 153 | + double pre_sigmoid_activation; |
| 154 | + |
| 155 | + for(i=0; i<this->n_hidden; i++) { |
| 156 | + h[i] = RBM_propup(this, v, this->W[i], this->hbias[i]); |
| 157 | + } |
| 158 | + |
| 159 | + for(i=0; i<this->n_visible; i++) { |
| 160 | + pre_sigmoid_activation = 0.0; |
| 161 | + for(j=0; j<this->n_hidden; j++) { |
| 162 | + pre_sigmoid_activation += this->W[j][i] * h[j]; |
| 163 | + } |
| 164 | + pre_sigmoid_activation += this->vbias[i]; |
| 165 | + |
| 166 | + reconstructed_v[i] = sigmoid(pre_sigmoid_activation); |
| 167 | + } |
| 168 | + |
| 169 | + free(h); |
| 170 | +} |
| 171 | + |
| 172 | + |
| 173 | + |
| 174 | + |
| 175 | +void test_rbm(void) { |
| 176 | + srand(0); |
| 177 | + |
| 178 | + int i, j, epoch; |
| 179 | + |
| 180 | + double learning_rate = 0.1; |
| 181 | + int training_epochs = 1000; |
| 182 | + int k = 1; |
| 183 | + |
| 184 | + int train_N = 6; |
| 185 | + int test_N = 2; |
| 186 | + int n_visible = 6; |
| 187 | + int n_hidden = 3; |
| 188 | + |
| 189 | + // training data |
| 190 | + int train_X[6][6] = { |
| 191 | + {1, 1, 1, 0, 0, 0}, |
| 192 | + {1, 0, 1, 0, 0, 0}, |
| 193 | + {1, 1, 1, 0, 0, 0}, |
| 194 | + {0, 0, 1, 1, 1, 0}, |
| 195 | + {0, 0, 1, 0, 1, 0}, |
| 196 | + {0, 0, 1, 1, 1, 0} |
| 197 | + }; |
| 198 | + |
| 199 | + // construct RBM |
| 200 | + RBM rbm; |
| 201 | + RBM__construct(&rbm, train_N, n_visible, n_hidden); |
| 202 | + |
| 203 | + // train |
| 204 | + for(epoch=0; epoch<training_epochs; epoch++) { |
| 205 | + for(i=0; i<train_N; i++) { |
| 206 | + RBM_contrastive_divergence(&rbm, train_X[i], learning_rate, k); |
| 207 | + } |
| 208 | + } |
| 209 | + |
| 210 | + |
| 211 | + // test data |
| 212 | + int test_X[2][6] = { |
| 213 | + {1, 1, 0, 0, 0, 0}, |
| 214 | + {0, 0, 0, 1, 1, 0} |
| 215 | + }; |
| 216 | + double reconstructed_X[2][6]; |
| 217 | + |
| 218 | + // test |
| 219 | + for(i=0; i<test_N; i++) { |
| 220 | + RBM_reconstruct(&rbm, test_X[i], reconstructed_X[i]); |
| 221 | + for(j=0; j<n_visible; j++) { |
| 222 | + printf("%.5f ", reconstructed_X[i][j]); |
| 223 | + } |
| 224 | + printf("\n"); |
| 225 | + } |
| 226 | + |
| 227 | + |
| 228 | + // destruct RBM |
| 229 | + RBM__destruct(&rbm); |
| 230 | +} |
| 231 | + |
| 232 | + |
| 233 | + |
| 234 | +int main(void) { |
| 235 | + test_rbm(); |
| 236 | + |
| 237 | + return 0; |
| 238 | +} |
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