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Adding sampling

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This commit is contained in:
Jean-Marc Valin 2018-11-26 11:04:41 -05:00
parent 91c9524af3
commit 575d8d6fa4
3 changed files with 38 additions and 5 deletions
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30
dnn/nnet.c
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@ -30,6 +30,7 @@
#include "config.h"
#endif
#include <stdlib.h>
#include <math.h>
#include "opus_types.h"
#include "arch.h"
@ -236,3 +237,32 @@ void compute_embedding(const EmbeddingLayer *layer, float *output, int input)
}
}
int sample_from_pdf(const float *pdf, int N, float exp_boost, float pdf_floor)
{
int i;
float sum, norm;
float r;
float tmp[DUAL_FC_OUT_SIZE];
celt_assert(N <= DUAL_FC_OUT_SIZE);
sum = 0;
/* Decrease the temperature of the sampling. */
for (i=0;i<N;i++)
{
tmp[i] = pow(pdf[i], 1.f+exp_boost);
sum += tmp[i];
}
norm = 1.f/sum;
/* Convert tmp to a CDF while subtracting the floor */
tmp[0] = MAX16(0, norm*tmp[0] - pdf_floor);
for (i=1;i<N;i++)
{
tmp[i] = tmp[i-1] + MAX16(0, norm*tmp[i] - pdf_floor);
}
/* Do the sampling (from the cdf). */
r = tmp[N-1] * ((float)rand()/RAND_MAX);
for (i=0;i<N-1;i++)
{
if (r > tmp[i]) return r;
}
return N-1;
}