blocky/liblocky/pathfinder.c

75 lines
1.8 KiB
C

#include "liblocky.h"
#include <assert.h>
#include <stdlib.h>
void blky_pathfinder_init(blky_pathfinder_t* pf) {
assert(pf->block_num > 0);
assert(pf->feat_bits > 0);
assert(pf->feat_bits < 32);
assert(pf->seed > 0);
assert(pf->block_num > (uint32_t) (1 << pf->feat_bits));
pf->step_last = NULL;
pf->step_bytes =
sizeof(blky_pathfinder_step_t) +
sizeof(uint32_t)*(pf->block_num-1);
pf->probs = calloc(sizeof(*pf->probs), pf->block_num);
assert(pf->probs);
pf->probs_prev = calloc(sizeof(*pf->probs_prev), pf->block_num);
assert(pf->probs_prev);
}
void blky_pathfinder_deinit(blky_pathfinder_t* pf) {
free(pf->probs);
free(pf->probs_prev);
blky_pathfinder_step_t* step = pf->step_last;
while (step) {
blky_pathfinder_step_t* temp = step->prev;
free(step);
step = temp;
}
}
void blky_pathfinder_feed(blky_pathfinder_t* pf, const double* probs) {
double* temp = pf->probs;
pf->probs = pf->probs_prev;
pf->probs_prev = temp;
blky_pathfinder_step_t* step = NULL;
if (++pf->steps > 1) {
step = calloc(pf->step_bytes, 1);
assert(step);
}
const uint32_t feat_max = 1 << pf->feat_bits;
assert(feat_max < pf->block_num);
pf->seed = blky_numeric_xorshift64(pf->seed);
for (uint32_t bi = 0; bi < pf->block_num; ++bi) {
const double prob = probs[bi];
for (uint32_t pbi = 0; pbi < pf->block_num; ++pbi) {
for (uint32_t fi = 0; fi < feat_max; ++fi) {
if (blky_numeric_hop(pbi, fi, pf->seed)%pf->block_num != bi) continue;
const double sum = pf->probs_prev[pbi] + prob;
if (pf->probs[bi] < sum) {
pf->probs[bi] = sum;
if (step) step->indices[bi] = pbi;
}
}
}
}
if (step) {
step->prev = pf->step_last;
pf->step_last = step;
}
}