blocky/liblocky/pathfinder.c
2022-06-22 11:49:01 +09:00

69 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->step_branch > 0);
assert(pf->seed > 0);
assert(pf->block_num >= pf->step_branch);
assert(pf->hopping_algo == BLKY_PATHFINDER_HOPPING_ALGO_XORSHFIT);
pf->step_first = NULL;
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);
}
void blky_pathfinder_feed(blky_pathfinder_t* pf, const double* probs) {
blky_pathfinder_step_t* step = NULL;
if (++pf->steps > 1) {
step = calloc(pf->step_bytes, 1);
assert(step);
}
for (uint32_t bi = 0; bi < pf->block_num; ++bi) {
const double prob = probs[bi];
const uint64_t pbase = blky_numeric_xorshift64_rev(bi);
for (uint32_t si = 0; si < pf->step_branch; ++si) {
const uint64_t prev_seed = pbase - si*pf->block_num/pf->step_branch;
const uint32_t prev_bi = (uint32_t) (prev_seed % pf->block_num);
const double prev_prob = pf->probs_prev[prev_bi];
const double sum = prev_prob + prob;
if (pf->probs[bi] < sum) {
pf->probs[bi] = sum;
if (step) step->indices[prev_bi] = bi;
}
}
}
if (step) {
if (pf->step_last) {
pf->step_last->next = step;
pf->step_last = step;
} else {
pf->step_first = pf->step_last = step;
}
}
double* temp = pf->probs;
pf->probs = pf->probs_prev;
pf->probs_prev = temp;
}