diff options
Diffstat (limited to 'media/pocketsphinx/src/ps_lattice.c')
| -rw-r--r-- | media/pocketsphinx/src/ps_lattice.c | 1940 |
1 files changed, 0 insertions, 1940 deletions
diff --git a/media/pocketsphinx/src/ps_lattice.c b/media/pocketsphinx/src/ps_lattice.c deleted file mode 100644 index 6f44a282b..000000000 --- a/media/pocketsphinx/src/ps_lattice.c +++ /dev/null @@ -1,1940 +0,0 @@ -/* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */ -/* ==================================================================== - * Copyright (c) 2008 Carnegie Mellon University. All rights - * reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in - * the documentation and/or other materials provided with the - * distribution. - * - * This work was supported in part by funding from the Defense Advanced - * Research Projects Agency and the National Science Foundation of the - * United States of America, and the CMU Sphinx Speech Consortium. - * - * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND - * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, - * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR - * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY - * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT - * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE - * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - * - * ==================================================================== - * - */ - -/** - * @file ps_lattice.c Word graph search. - */ - -/* System headers. */ -#include <assert.h> -#include <string.h> -#include <math.h> - -/* SphinxBase headers. */ -#include <sphinxbase/ckd_alloc.h> -#include <sphinxbase/listelem_alloc.h> -#include <sphinxbase/strfuncs.h> -#include <sphinxbase/err.h> -#include <sphinxbase/pio.h> - -/* Local headers. */ -#include "pocketsphinx_internal.h" -#include "ps_lattice_internal.h" -#include "ngram_search.h" -#include "dict.h" - -/* - * Create a directed link between "from" and "to" nodes, but if a link already exists, - * choose one with the best ascr. - */ -void -ps_lattice_link(ps_lattice_t *dag, ps_latnode_t *from, ps_latnode_t *to, - int32 score, int32 ef) -{ - latlink_list_t *fwdlink; - - /* Look for an existing link between "from" and "to" nodes */ - for (fwdlink = from->exits; fwdlink; fwdlink = fwdlink->next) - if (fwdlink->link->to == to) - break; - - if (fwdlink == NULL) { - latlink_list_t *revlink; - ps_latlink_t *link; - - /* No link between the two nodes; create a new one */ - link = listelem_malloc(dag->latlink_alloc); - fwdlink = listelem_malloc(dag->latlink_list_alloc); - revlink = listelem_malloc(dag->latlink_list_alloc); - - link->from = from; - link->to = to; - link->ascr = score; - link->ef = ef; - link->best_prev = NULL; - - fwdlink->link = revlink->link = link; - fwdlink->next = from->exits; - from->exits = fwdlink; - revlink->next = to->entries; - to->entries = revlink; - } - else { - /* Link already exists; just retain the best ascr */ - if (score BETTER_THAN fwdlink->link->ascr) { - fwdlink->link->ascr = score; - fwdlink->link->ef = ef; - } - } -} - -void -ps_lattice_penalize_fillers(ps_lattice_t *dag, int32 silpen, int32 fillpen) -{ - ps_latnode_t *node; - - for (node = dag->nodes; node; node = node->next) { - latlink_list_t *linklist; - if (node != dag->start && node != dag->end && dict_filler_word(dag->dict, node->basewid)) { - for (linklist = node->entries; linklist; linklist = linklist->next) - linklist->link->ascr += (node->basewid == dag->silence) ? silpen : fillpen; - } - } -} - -static void -delete_node(ps_lattice_t *dag, ps_latnode_t *node) -{ - latlink_list_t *x, *next_x; - - for (x = node->exits; x; x = next_x) { - next_x = x->next; - x->link->from = NULL; - listelem_free(dag->latlink_list_alloc, x); - } - for (x = node->entries; x; x = next_x) { - next_x = x->next; - x->link->to = NULL; - listelem_free(dag->latlink_list_alloc, x); - } - listelem_free(dag->latnode_alloc, node); -} - - -static void -remove_dangling_links(ps_lattice_t *dag, ps_latnode_t *node) -{ - latlink_list_t *x, *prev_x, *next_x; - - prev_x = NULL; - for (x = node->exits; x; x = next_x) { - next_x = x->next; - if (x->link->to == NULL) { - if (prev_x) - prev_x->next = next_x; - else - node->exits = next_x; - listelem_free(dag->latlink_alloc, x->link); - listelem_free(dag->latlink_list_alloc, x); - } - else - prev_x = x; - } - prev_x = NULL; - for (x = node->entries; x; x = next_x) { - next_x = x->next; - if (x->link->from == NULL) { - if (prev_x) - prev_x->next = next_x; - else - node->entries = next_x; - listelem_free(dag->latlink_alloc, x->link); - listelem_free(dag->latlink_list_alloc, x); - } - else - prev_x = x; - } -} - -void -ps_lattice_delete_unreachable(ps_lattice_t *dag) -{ - ps_latnode_t *node, *prev_node, *next_node; - int i; - - /* Remove unreachable nodes from the list of nodes. */ - prev_node = NULL; - for (node = dag->nodes; node; node = next_node) { - next_node = node->next; - if (!node->reachable) { - if (prev_node) - prev_node->next = next_node; - else - dag->nodes = next_node; - /* Delete this node and NULLify links to it. */ - delete_node(dag, node); - } - else - prev_node = node; - } - - /* Remove all links to and from unreachable nodes. */ - i = 0; - for (node = dag->nodes; node; node = node->next) { - /* Assign sequence numbers. */ - node->id = i++; - - /* We should obviously not encounter unreachable nodes here! */ - assert(node->reachable); - - /* Remove all links that go nowhere. */ - remove_dangling_links(dag, node); - } -} - -int32 -ps_lattice_write(ps_lattice_t *dag, char const *filename) -{ - FILE *fp; - int32 i; - ps_latnode_t *d, *initial, *final; - - initial = dag->start; - final = dag->end; - - E_INFO("Writing lattice file: %s\n", filename); - if ((fp = fopen(filename, "w")) == NULL) { - E_ERROR_SYSTEM("Failed to open lattice file '%s' for writing", filename); - return -1; - } - - /* Stupid Sphinx-III lattice code expects 'getcwd:' here */ - fprintf(fp, "# getcwd: /this/is/bogus\n"); - fprintf(fp, "# -logbase %e\n", logmath_get_base(dag->lmath)); - fprintf(fp, "#\n"); - - fprintf(fp, "Frames %d\n", dag->n_frames); - fprintf(fp, "#\n"); - - for (i = 0, d = dag->nodes; d; d = d->next, i++); - fprintf(fp, - "Nodes %d (NODEID WORD STARTFRAME FIRST-ENDFRAME LAST-ENDFRAME)\n", - i); - for (i = 0, d = dag->nodes; d; d = d->next, i++) { - d->id = i; - fprintf(fp, "%d %s %d %d %d ; %d\n", - i, dict_wordstr(dag->dict, d->wid), - d->sf, d->fef, d->lef, d->node_id); - } - fprintf(fp, "#\n"); - - fprintf(fp, "Initial %d\nFinal %d\n", initial->id, final->id); - fprintf(fp, "#\n"); - - /* Don't bother with this, it's not used by anything. */ - fprintf(fp, "BestSegAscr %d (NODEID ENDFRAME ASCORE)\n", - 0 /* #BPTable entries */ ); - fprintf(fp, "#\n"); - - fprintf(fp, "Edges (FROM-NODEID TO-NODEID ASCORE)\n"); - for (d = dag->nodes; d; d = d->next) { - latlink_list_t *l; - for (l = d->exits; l; l = l->next) { - if (l->link->ascr WORSE_THAN WORST_SCORE || l->link->ascr BETTER_THAN 0) - continue; - fprintf(fp, "%d %d %d\n", - d->id, l->link->to->id, l->link->ascr << SENSCR_SHIFT); - } - } - fprintf(fp, "End\n"); - fclose(fp); - - return 0; -} - -int32 -ps_lattice_write_htk(ps_lattice_t *dag, char const *filename) -{ - FILE *fp; - ps_latnode_t *d, *initial, *final; - int32 j, n_links, n_nodes; - - initial = dag->start; - final = dag->end; - - E_INFO("Writing lattice file: %s\n", filename); - if ((fp = fopen(filename, "w")) == NULL) { - E_ERROR_SYSTEM("Failed to open lattice file '%s' for writing", filename); - return -1; - } - - for (n_links = n_nodes = 0, d = dag->nodes; d; d = d->next) { - latlink_list_t *l; - if (!d->reachable) - continue; - d->id = n_nodes; - for (l = d->exits; l; l = l->next) { - if (l->link->to == NULL || !l->link->to->reachable) - continue; - if (l->link->ascr WORSE_THAN WORST_SCORE || l->link->ascr BETTER_THAN 0) - continue; - ++n_links; - } - ++n_nodes; - } - - fprintf(fp, "# Lattice generated by PocketSphinx\n"); - fprintf(fp, "#\n# Header\n#\n"); - fprintf(fp, "VERSION=1.0\n"); - fprintf(fp, "start=%d\n", initial->id); - fprintf(fp, "end=%d\n", final->id); - fprintf(fp, "#\n"); - - fprintf(fp, "N=%d\tL=%d\n", n_nodes, n_links); - fprintf(fp, "#\n# Node definitions\n#\n"); - for (d = dag->nodes; d; d = d->next) { - char const *word = dict_wordstr(dag->dict, d->wid); - char const *c = strrchr(word, '('); - int altpron = 1; - if (!d->reachable) - continue; - if (c) - altpron = atoi(c + 1); - word = dict_basestr(dag->dict, d->wid); - if (d->wid == dict_startwid(dag->dict)) - word = "!SENT_START"; - else if (d->wid == dict_finishwid(dag->dict)) - word = "!SENT_END"; - else if (dict_filler_word(dag->dict, d->wid)) - word = "!NULL"; - fprintf(fp, "I=%d\tt=%.2f\tW=%s\tv=%d\n", - d->id, (double)d->sf / dag->frate, - word, altpron); - } - fprintf(fp, "#\n# Link definitions\n#\n"); - for (j = 0, d = dag->nodes; d; d = d->next) { - latlink_list_t *l; - if (!d->reachable) - continue; - for (l = d->exits; l; l = l->next) { - if (l->link->to == NULL || !l->link->to->reachable) - continue; - if (l->link->ascr WORSE_THAN WORST_SCORE || l->link->ascr BETTER_THAN 0) - continue; - fprintf(fp, "J=%d\tS=%d\tE=%d\ta=%f\tp=%g\n", j++, - d->id, l->link->to->id, - logmath_log_to_ln(dag->lmath, l->link->ascr << SENSCR_SHIFT), - logmath_exp(dag->lmath, l->link->alpha + l->link->beta - dag->norm)); - } - } - fclose(fp); - - return 0; -} - -/* Read parameter from a lattice file*/ -static int -dag_param_read(lineiter_t *li, char *param) -{ - int32 n; - - while ((li = lineiter_next(li)) != NULL) { - char *c; - - /* Ignore comments. */ - if (li->buf[0] == '#') - continue; - - /* Find the first space. */ - c = strchr(li->buf, ' '); - if (c == NULL) continue; - - /* Check that the first field equals param and that there's a number after it. */ - if (strncmp(li->buf, param, strlen(param)) == 0 - && sscanf(c + 1, "%d", &n) == 1) - return n; - } - return -1; -} - -/* Mark every node that has a path to the argument dagnode as "reachable". */ -static void -dag_mark_reachable(ps_latnode_t * d) -{ - latlink_list_t *l; - - d->reachable = 1; - for (l = d->entries; l; l = l->next) - if (l->link->from && !l->link->from->reachable) - dag_mark_reachable(l->link->from); -} - -ps_lattice_t * -ps_lattice_read(ps_decoder_t *ps, - char const *file) -{ - FILE *fp; - int32 ispipe; - lineiter_t *line; - float64 lb; - float32 logratio; - ps_latnode_t *tail; - ps_latnode_t **darray; - ps_lattice_t *dag; - int i, k, n_nodes; - int32 pip, silpen, fillpen; - - dag = ckd_calloc(1, sizeof(*dag)); - - if (ps) { - dag->search = ps->search; - dag->dict = dict_retain(ps->dict); - dag->lmath = logmath_retain(ps->lmath); - dag->dict = dict_init(NULL, NULL, dag->lmath); - dag->frate = cmd_ln_int32_r(dag->search->config, "-frate"); - } - else { - dag->dict = dict_init(NULL, NULL, dag->lmath); - dag->lmath = logmath_init(1.0001, 0, FALSE); - dag->frate = 100; - } - dag->silence = dict_silwid(dag->dict); - dag->latnode_alloc = listelem_alloc_init(sizeof(ps_latnode_t)); - dag->latlink_alloc = listelem_alloc_init(sizeof(ps_latlink_t)); - dag->latlink_list_alloc = listelem_alloc_init(sizeof(latlink_list_t)); - dag->refcount = 1; - - tail = NULL; - darray = NULL; - - E_INFO("Reading DAG file: %s\n", file); - if ((fp = fopen_compchk(file, &ispipe)) == NULL) { - E_ERROR_SYSTEM("Failed to open DAG file '%s' for reading", file); - return NULL; - } - line = lineiter_start(fp); - - /* Read and verify logbase (ONE BIG HACK!!) */ - if (line == NULL) { - E_ERROR("Premature EOF(%s)\n", file); - goto load_error; - } - if (strncmp(line->buf, "# getcwd: ", 10) != 0) { - E_ERROR("%s does not begin with '# getcwd: '\n%s", file, line->buf); - goto load_error; - } - if ((line = lineiter_next(line)) == NULL) { - E_ERROR("Premature EOF(%s)\n", file); - goto load_error; - } - if ((strncmp(line->buf, "# -logbase ", 11) != 0) - || (sscanf(line->buf + 11, "%lf", &lb) != 1)) { - E_WARN("%s: Cannot find -logbase in header\n", file); - lb = 1.0001; - } - logratio = 1.0f; - if (dag->lmath == NULL) - dag->lmath = logmath_init(lb, 0, TRUE); - else { - float32 pb = logmath_get_base(dag->lmath); - if (fabs(lb - pb) >= 0.0001) { - E_WARN("Inconsistent logbases: %f vs %f: will compensate\n", lb, pb); - logratio = (float32)(log(lb) / log(pb)); - E_INFO("Lattice log ratio: %f\n", logratio); - } - } - /* Read Frames parameter */ - dag->n_frames = dag_param_read(line, "Frames"); - if (dag->n_frames <= 0) { - E_ERROR("Frames parameter missing or invalid\n"); - goto load_error; - } - /* Read Nodes parameter */ - n_nodes = dag_param_read(line, "Nodes"); - if (n_nodes <= 0) { - E_ERROR("Nodes parameter missing or invalid\n"); - goto load_error; - } - - /* Read nodes */ - darray = ckd_calloc(n_nodes, sizeof(*darray)); - for (i = 0; i < n_nodes; i++) { - ps_latnode_t *d; - int32 w; - int seqid, sf, fef, lef; - char wd[256]; - - if ((line = lineiter_next(line)) == NULL) { - E_ERROR("Premature EOF while loading Nodes(%s)\n", file); - goto load_error; - } - - if ((k = - sscanf(line->buf, "%d %255s %d %d %d", &seqid, wd, &sf, &fef, - &lef)) != 5) { - E_ERROR("Cannot parse line: %s, value of count %d\n", line->buf, k); - goto load_error; - } - - w = dict_wordid(dag->dict, wd); - if (w < 0) { - if (dag->search == NULL) { - char *ww = ckd_salloc(wd); - if (dict_word2basestr(ww) != -1) { - if (dict_wordid(dag->dict, ww) == BAD_S3WID) - dict_add_word(dag->dict, ww, NULL, 0); - } - ckd_free(ww); - w = dict_add_word(dag->dict, wd, NULL, 0); - } - if (w < 0) { - E_ERROR("Unknown word in line: %s\n", line->buf); - goto load_error; - } - } - - if (seqid != i) { - E_ERROR("Seqno error: %s\n", line->buf); - goto load_error; - } - - d = listelem_malloc(dag->latnode_alloc); - darray[i] = d; - d->wid = w; - d->basewid = dict_basewid(dag->dict, w); - d->id = seqid; - d->sf = sf; - d->fef = fef; - d->lef = lef; - d->reachable = 0; - d->exits = d->entries = NULL; - d->next = NULL; - - if (!dag->nodes) - dag->nodes = d; - else - tail->next = d; - tail = d; - } - - /* Read initial node ID */ - k = dag_param_read(line, "Initial"); - if ((k < 0) || (k >= n_nodes)) { - E_ERROR("Initial node parameter missing or invalid\n"); - goto load_error; - } - dag->start = darray[k]; - - /* Read final node ID */ - k = dag_param_read(line, "Final"); - if ((k < 0) || (k >= n_nodes)) { - E_ERROR("Final node parameter missing or invalid\n"); - goto load_error; - } - dag->end = darray[k]; - - /* Read bestsegscore entries and ignore them. */ - if ((k = dag_param_read(line, "BestSegAscr")) < 0) { - E_ERROR("BestSegAscr parameter missing\n"); - goto load_error; - } - for (i = 0; i < k; i++) { - if ((line = lineiter_next(line)) == NULL) { - E_ERROR("Premature EOF while (%s) ignoring BestSegAscr\n", - line); - goto load_error; - } - } - - /* Read in edges. */ - while ((line = lineiter_next(line)) != NULL) { - if (line->buf[0] == '#') - continue; - if (0 == strncmp(line->buf, "Edges", 5)) - break; - } - if (line == NULL) { - E_ERROR("Edges missing\n"); - goto load_error; - } - while ((line = lineiter_next(line)) != NULL) { - int from, to, ascr; - ps_latnode_t *pd, *d; - - if (sscanf(line->buf, "%d %d %d", &from, &to, &ascr) != 3) - break; - if (ascr WORSE_THAN WORST_SCORE) - continue; - pd = darray[from]; - d = darray[to]; - if (logratio != 1.0f) - ascr = (int32)(ascr * logratio); - ps_lattice_link(dag, pd, d, ascr, d->sf - 1); - } - if (strcmp(line->buf, "End\n") != 0) { - E_ERROR("Terminating 'End' missing\n"); - goto load_error; - } - lineiter_free(line); - fclose_comp(fp, ispipe); - ckd_free(darray); - - /* Minor hack: If the final node is a filler word and not </s>, - * then set its base word ID to </s>, so that the language model - * scores won't be screwed up. */ - if (dict_filler_word(dag->dict, dag->end->wid)) - dag->end->basewid = dag->search - ? ps_search_finish_wid(dag->search) - : dict_wordid(dag->dict, S3_FINISH_WORD); - - /* Mark reachable from dag->end */ - dag_mark_reachable(dag->end); - - /* Free nodes unreachable from dag->end and their links */ - ps_lattice_delete_unreachable(dag); - - if (ps) { - /* Build links around silence and filler words, since they do - * not exist in the language model. FIXME: This is - * potentially buggy, as we already do this before outputing - * lattices. */ - pip = logmath_log(dag->lmath, cmd_ln_float32_r(ps->config, "-pip")); - silpen = pip + logmath_log(dag->lmath, - cmd_ln_float32_r(ps->config, "-silprob")); - fillpen = pip + logmath_log(dag->lmath, - cmd_ln_float32_r(ps->config, "-fillprob")); - ps_lattice_penalize_fillers(dag, silpen, fillpen); - } - - return dag; - - load_error: - E_ERROR("Failed to load %s\n", file); - lineiter_free(line); - if (fp) fclose_comp(fp, ispipe); - ckd_free(darray); - return NULL; -} - -int -ps_lattice_n_frames(ps_lattice_t *dag) -{ - return dag->n_frames; -} - -ps_lattice_t * -ps_lattice_init_search(ps_search_t *search, int n_frame) -{ - ps_lattice_t *dag; - - dag = ckd_calloc(1, sizeof(*dag)); - dag->search = search; - dag->dict = dict_retain(search->dict); - dag->lmath = logmath_retain(search->acmod->lmath); - dag->frate = cmd_ln_int32_r(dag->search->config, "-frate"); - dag->silence = dict_silwid(dag->dict); - dag->n_frames = n_frame; - dag->latnode_alloc = listelem_alloc_init(sizeof(ps_latnode_t)); - dag->latlink_alloc = listelem_alloc_init(sizeof(ps_latlink_t)); - dag->latlink_list_alloc = listelem_alloc_init(sizeof(latlink_list_t)); - dag->refcount = 1; - return dag; -} - -ps_lattice_t * -ps_lattice_retain(ps_lattice_t *dag) -{ - ++dag->refcount; - return dag; -} - -int -ps_lattice_free(ps_lattice_t *dag) -{ - if (dag == NULL) - return 0; - if (--dag->refcount > 0) - return dag->refcount; - logmath_free(dag->lmath); - dict_free(dag->dict); - listelem_alloc_free(dag->latnode_alloc); - listelem_alloc_free(dag->latlink_alloc); - listelem_alloc_free(dag->latlink_list_alloc); - ckd_free(dag->hyp_str); - ckd_free(dag); - return 0; -} - -logmath_t * -ps_lattice_get_logmath(ps_lattice_t *dag) -{ - return dag->lmath; -} - -ps_latnode_iter_t * -ps_latnode_iter(ps_lattice_t *dag) -{ - return dag->nodes; -} - -ps_latnode_iter_t * -ps_latnode_iter_next(ps_latnode_iter_t *itor) -{ - return itor->next; -} - -void -ps_latnode_iter_free(ps_latnode_iter_t *itor) -{ - /* Do absolutely nothing. */ -} - -ps_latnode_t * -ps_latnode_iter_node(ps_latnode_iter_t *itor) -{ - return itor; -} - -int -ps_latnode_times(ps_latnode_t *node, int16 *out_fef, int16 *out_lef) -{ - if (out_fef) *out_fef = (int16)node->fef; - if (out_lef) *out_lef = (int16)node->lef; - return node->sf; -} - -char const * -ps_latnode_word(ps_lattice_t *dag, ps_latnode_t *node) -{ - return dict_wordstr(dag->dict, node->wid); -} - -char const * -ps_latnode_baseword(ps_lattice_t *dag, ps_latnode_t *node) -{ - return dict_wordstr(dag->dict, node->basewid); -} - -int32 -ps_latnode_prob(ps_lattice_t *dag, ps_latnode_t *node, - ps_latlink_t **out_link) -{ - latlink_list_t *links; - int32 bestpost = logmath_get_zero(dag->lmath); - - for (links = node->exits; links; links = links->next) { - int32 post = links->link->alpha + links->link->beta - dag->norm; - if (post > bestpost) { - if (out_link) *out_link = links->link; - bestpost = post; - } - } - return bestpost; -} - -ps_latlink_iter_t * -ps_latnode_exits(ps_latnode_t *node) -{ - return node->exits; -} - -ps_latlink_iter_t * -ps_latnode_entries(ps_latnode_t *node) -{ - return node->entries; -} - -ps_latlink_iter_t * -ps_latlink_iter_next(ps_latlink_iter_t *itor) -{ - return itor->next; -} - -void -ps_latlink_iter_free(ps_latlink_iter_t *itor) -{ - /* Do absolutely nothing. */ -} - -ps_latlink_t * -ps_latlink_iter_link(ps_latlink_iter_t *itor) -{ - return itor->link; -} - -int -ps_latlink_times(ps_latlink_t *link, int16 *out_sf) -{ - if (out_sf) { - if (link->from) { - *out_sf = link->from->sf; - } - else { - *out_sf = 0; - } - } - return link->ef; -} - -ps_latnode_t * -ps_latlink_nodes(ps_latlink_t *link, ps_latnode_t **out_src) -{ - if (out_src) *out_src = link->from; - return link->to; -} - -char const * -ps_latlink_word(ps_lattice_t *dag, ps_latlink_t *link) -{ - if (link->from == NULL) - return NULL; - return dict_wordstr(dag->dict, link->from->wid); -} - -char const * -ps_latlink_baseword(ps_lattice_t *dag, ps_latlink_t *link) -{ - if (link->from == NULL) - return NULL; - return dict_wordstr(dag->dict, link->from->basewid); -} - -ps_latlink_t * -ps_latlink_pred(ps_latlink_t *link) -{ - return link->best_prev; -} - -int32 -ps_latlink_prob(ps_lattice_t *dag, ps_latlink_t *link, int32 *out_ascr) -{ - int32 post = link->alpha + link->beta - dag->norm; - if (out_ascr) *out_ascr = link->ascr << SENSCR_SHIFT; - return post; -} - -char const * -ps_lattice_hyp(ps_lattice_t *dag, ps_latlink_t *link) -{ - ps_latlink_t *l; - size_t len; - char *c; - - /* Backtrace once to get hypothesis length. */ - len = 0; - /* FIXME: There may not be a search, but actually there should be a dict. */ - if (dict_real_word(dag->dict, link->to->basewid)) { - char *wstr = dict_wordstr(dag->dict, link->to->basewid); - if (wstr != NULL) - len += strlen(wstr) + 1; - } - for (l = link; l; l = l->best_prev) { - if (dict_real_word(dag->dict, l->from->basewid)) { - char *wstr = dict_wordstr(dag->dict, l->from->basewid); - if (wstr != NULL) - len += strlen(wstr) + 1; - } - } - - /* Backtrace again to construct hypothesis string. */ - ckd_free(dag->hyp_str); - dag->hyp_str = ckd_calloc(1, len+1); /* extra one incase the hyp is empty */ - c = dag->hyp_str + len - 1; - if (dict_real_word(dag->dict, link->to->basewid)) { - char *wstr = dict_wordstr(dag->dict, link->to->basewid); - if (wstr != NULL) { - len = strlen(wstr); - c -= len; - memcpy(c, wstr, len); - if (c > dag->hyp_str) { - --c; - *c = ' '; - } - } - } - for (l = link; l; l = l->best_prev) { - if (dict_real_word(dag->dict, l->from->basewid)) { - char *wstr = dict_wordstr(dag->dict, l->from->basewid); - if (wstr != NULL) { - len = strlen(wstr); - c -= len; - memcpy(c, wstr, len); - if (c > dag->hyp_str) { - --c; - *c = ' '; - } - } - } - } - - return dag->hyp_str; -} - -static void -ps_lattice_compute_lscr(ps_seg_t *seg, ps_latlink_t *link, int to) -{ - ngram_model_t *lmset; - - /* Language model score is included in the link score for FSG - * search. FIXME: Of course, this is sort of a hack :( */ - if (0 != strcmp(ps_search_name(seg->search), PS_SEARCH_NGRAM)) { - seg->lback = 1; /* Unigram... */ - seg->lscr = 0; - return; - } - - lmset = ((ngram_search_t *)seg->search)->lmset; - - if (link->best_prev == NULL) { - if (to) /* Sentence has only two words. */ - seg->lscr = ngram_bg_score(lmset, link->to->basewid, - link->from->basewid, &seg->lback) - >> SENSCR_SHIFT; - else {/* This is the start symbol, its lscr is always 0. */ - seg->lscr = 0; - seg->lback = 1; - } - } - else { - /* Find the two predecessor words. */ - if (to) { - seg->lscr = ngram_tg_score(lmset, link->to->basewid, - link->from->basewid, - link->best_prev->from->basewid, - &seg->lback) >> SENSCR_SHIFT; - } - else { - if (link->best_prev->best_prev) - seg->lscr = ngram_tg_score(lmset, link->from->basewid, - link->best_prev->from->basewid, - link->best_prev->best_prev->from->basewid, - &seg->lback) >> SENSCR_SHIFT; - else - seg->lscr = ngram_bg_score(lmset, link->from->basewid, - link->best_prev->from->basewid, - &seg->lback) >> SENSCR_SHIFT; - } - } -} - -static void -ps_lattice_link2itor(ps_seg_t *seg, ps_latlink_t *link, int to) -{ - dag_seg_t *itor = (dag_seg_t *)seg; - ps_latnode_t *node; - - if (to) { - node = link->to; - seg->ef = node->lef; - seg->prob = 0; /* norm + beta - norm */ - } - else { - latlink_list_t *x; - ps_latnode_t *n; - logmath_t *lmath = ps_search_acmod(seg->search)->lmath; - - node = link->from; - seg->ef = link->ef; - seg->prob = link->alpha + link->beta - itor->norm; - /* Sum over all exits for this word and any alternate - pronunciations at the same frame. */ - for (n = node; n; n = n->alt) { - for (x = n->exits; x; x = x->next) { - if (x->link == link) - continue; - seg->prob = logmath_add(lmath, seg->prob, - x->link->alpha + x->link->beta - itor->norm); - } - } - } - seg->word = dict_wordstr(ps_search_dict(seg->search), node->wid); - seg->sf = node->sf; - seg->ascr = link->ascr << SENSCR_SHIFT; - /* Compute language model score from best predecessors. */ - ps_lattice_compute_lscr(seg, link, to); -} - -static void -ps_lattice_seg_free(ps_seg_t *seg) -{ - dag_seg_t *itor = (dag_seg_t *)seg; - - ckd_free(itor->links); - ckd_free(itor); -} - -static ps_seg_t * -ps_lattice_seg_next(ps_seg_t *seg) -{ - dag_seg_t *itor = (dag_seg_t *)seg; - - ++itor->cur; - if (itor->cur == itor->n_links + 1) { - ps_lattice_seg_free(seg); - return NULL; - } - else if (itor->cur == itor->n_links) { - /* Re-use the last link but with the "to" node. */ - ps_lattice_link2itor(seg, itor->links[itor->cur - 1], TRUE); - } - else { - ps_lattice_link2itor(seg, itor->links[itor->cur], FALSE); - } - - return seg; -} - -static ps_segfuncs_t ps_lattice_segfuncs = { - /* seg_next */ ps_lattice_seg_next, - /* seg_free */ ps_lattice_seg_free -}; - -ps_seg_t * -ps_lattice_seg_iter(ps_lattice_t *dag, ps_latlink_t *link, float32 lwf) -{ - dag_seg_t *itor; - ps_latlink_t *l; - int cur; - - /* Calling this an "iterator" is a bit of a misnomer since we have - * to get the entire backtrace in order to produce it. - */ - itor = ckd_calloc(1, sizeof(*itor)); - itor->base.vt = &ps_lattice_segfuncs; - itor->base.search = dag->search; - itor->base.lwf = lwf; - itor->n_links = 0; - itor->norm = dag->norm; - - for (l = link; l; l = l->best_prev) { - ++itor->n_links; - } - if (itor->n_links == 0) { - ckd_free(itor); - return NULL; - } - - itor->links = ckd_calloc(itor->n_links, sizeof(*itor->links)); - cur = itor->n_links - 1; - for (l = link; l; l = l->best_prev) { - itor->links[cur] = l; - --cur; - } - - ps_lattice_link2itor((ps_seg_t *)itor, itor->links[0], FALSE); - return (ps_seg_t *)itor; -} - -latlink_list_t * -latlink_list_new(ps_lattice_t *dag, ps_latlink_t *link, latlink_list_t *next) -{ - latlink_list_t *ll; - - ll = listelem_malloc(dag->latlink_list_alloc); - ll->link = link; - ll->next = next; - - return ll; -} - -void -ps_lattice_pushq(ps_lattice_t *dag, ps_latlink_t *link) -{ - if (dag->q_head == NULL) - dag->q_head = dag->q_tail = latlink_list_new(dag, link, NULL); - else { - dag->q_tail->next = latlink_list_new(dag, link, NULL); - dag->q_tail = dag->q_tail->next; - } - -} - -ps_latlink_t * -ps_lattice_popq(ps_lattice_t *dag) -{ - latlink_list_t *x; - ps_latlink_t *link; - - if (dag->q_head == NULL) - return NULL; - link = dag->q_head->link; - x = dag->q_head->next; - listelem_free(dag->latlink_list_alloc, dag->q_head); - dag->q_head = x; - if (dag->q_head == NULL) - dag->q_tail = NULL; - return link; -} - -void -ps_lattice_delq(ps_lattice_t *dag) -{ - while (ps_lattice_popq(dag)) { - /* Do nothing. */ - } -} - -ps_latlink_t * -ps_lattice_traverse_edges(ps_lattice_t *dag, ps_latnode_t *start, ps_latnode_t *end) -{ - ps_latnode_t *node; - latlink_list_t *x; - - /* Cancel any unfinished traversal. */ - ps_lattice_delq(dag); - - /* Initialize node fanin counts and path scores. */ - for (node = dag->nodes; node; node = node->next) - node->info.fanin = 0; - for (node = dag->nodes; node; node = node->next) { - for (x = node->exits; x; x = x->next) - (x->link->to->info.fanin)++; - } - - /* Initialize agenda with all exits from start. */ - if (start == NULL) start = dag->start; - for (x = start->exits; x; x = x->next) - ps_lattice_pushq(dag, x->link); - - /* Pull the first edge off the queue. */ - return ps_lattice_traverse_next(dag, end); -} - -ps_latlink_t * -ps_lattice_traverse_next(ps_lattice_t *dag, ps_latnode_t *end) -{ - ps_latlink_t *next; - - next = ps_lattice_popq(dag); - if (next == NULL) - return NULL; - - /* Decrease fanin count for destination node and expand outgoing - * edges if all incoming edges have been seen. */ - --next->to->info.fanin; - if (next->to->info.fanin == 0) { - latlink_list_t *x; - - if (end == NULL) end = dag->end; - if (next->to == end) { - /* If we have traversed all links entering the end node, - * clear the queue, causing future calls to this function - * to return NULL. */ - ps_lattice_delq(dag); - return next; - } - - /* Extend all outgoing edges. */ - for (x = next->to->exits; x; x = x->next) - ps_lattice_pushq(dag, x->link); - } - return next; -} - -ps_latlink_t * -ps_lattice_reverse_edges(ps_lattice_t *dag, ps_latnode_t *start, ps_latnode_t *end) -{ - ps_latnode_t *node; - latlink_list_t *x; - - /* Cancel any unfinished traversal. */ - ps_lattice_delq(dag); - - /* Initialize node fanout counts and path scores. */ - for (node = dag->nodes; node; node = node->next) { - node->info.fanin = 0; - for (x = node->exits; x; x = x->next) - ++node->info.fanin; - } - - /* Initialize agenda with all entries from end. */ - if (end == NULL) end = dag->end; - for (x = end->entries; x; x = x->next) - ps_lattice_pushq(dag, x->link); - - /* Pull the first edge off the queue. */ - return ps_lattice_reverse_next(dag, start); -} - -ps_latlink_t * -ps_lattice_reverse_next(ps_lattice_t *dag, ps_latnode_t *start) -{ - ps_latlink_t *next; - - next = ps_lattice_popq(dag); - if (next == NULL) - return NULL; - - /* Decrease fanout count for source node and expand incoming - * edges if all incoming edges have been seen. */ - --next->from->info.fanin; - if (next->from->info.fanin == 0) { - latlink_list_t *x; - - if (start == NULL) start = dag->start; - if (next->from == start) { - /* If we have traversed all links entering the start node, - * clear the queue, causing future calls to this function - * to return NULL. */ - ps_lattice_delq(dag); - return next; - } - - /* Extend all outgoing edges. */ - for (x = next->from->entries; x; x = x->next) - ps_lattice_pushq(dag, x->link); - } - return next; -} - -/* - * Find the best score from dag->start to end point of any link and - * use it to update links further down the path. This is like - * single-source shortest path search, except that it is done over - * edges rather than nodes, which allows us to do exact trigram scoring. - * - * Helpfully enough, we get half of the posterior probability - * calculation for free that way too. (interesting research topic: is - * there a reliable Viterbi analogue to word-level Forward-Backward - * like there is for state-level? Or, is it just lattice density?) - */ -ps_latlink_t * -ps_lattice_bestpath(ps_lattice_t *dag, ngram_model_t *lmset, - float32 lwf, float32 ascale) -{ - ps_search_t *search; - ps_latnode_t *node; - ps_latlink_t *link; - ps_latlink_t *bestend; - latlink_list_t *x; - logmath_t *lmath; - int32 bestescr; - - search = dag->search; - lmath = dag->lmath; - - /* Initialize path scores for all links exiting dag->start, and - * set all other scores to the minimum. Also initialize alphas to - * log-zero. */ - for (node = dag->nodes; node; node = node->next) { - for (x = node->exits; x; x = x->next) { - x->link->path_scr = MAX_NEG_INT32; - x->link->alpha = logmath_get_zero(lmath); - } - } - for (x = dag->start->exits; x; x = x->next) { - int32 n_used; - int16 to_is_fil; - - to_is_fil = dict_filler_word(ps_search_dict(search), x->link->to->basewid) && x->link->to != dag->end; - - /* Best path points to dag->start, obviously. */ - x->link->path_scr = x->link->ascr; - if (lmset && !to_is_fil) - x->link->path_scr += (ngram_bg_score(lmset, x->link->to->basewid, - ps_search_start_wid(search), &n_used) >> SENSCR_SHIFT) * lwf; - x->link->best_prev = NULL; - /* No predecessors for start links. */ - x->link->alpha = 0; - } - - /* Traverse the edges in the graph, updating path scores. */ - for (link = ps_lattice_traverse_edges(dag, NULL, NULL); - link; link = ps_lattice_traverse_next(dag, NULL)) { - int32 bprob, n_used; - int32 w3_wid, w2_wid; - int16 w3_is_fil, w2_is_fil; - ps_latlink_t *prev_link; - - /* Sanity check, we should not be traversing edges that - * weren't previously updated, otherwise nasty overflows will result. */ - assert(link->path_scr != MAX_NEG_INT32); - - /* Find word predecessor if from-word is filler */ - w3_wid = link->from->basewid; - w2_wid = link->to->basewid; - w3_is_fil = dict_filler_word(ps_search_dict(search), link->from->basewid) && link->from != dag->start; - w2_is_fil = dict_filler_word(ps_search_dict(search), w2_wid) && link->to != dag->end; - prev_link = link; - - if (w3_is_fil) { - while (prev_link->best_prev != NULL) { - prev_link = prev_link->best_prev; - w3_wid = prev_link->from->basewid; - if (!dict_filler_word(ps_search_dict(search), w3_wid) || prev_link->from == dag->start) { - w3_is_fil = FALSE; - break; - } - } - } - - /* Calculate common bigram probability for all alphas. */ - if (lmset && !w3_is_fil && !w2_is_fil) - bprob = ngram_ng_prob(lmset, w2_wid, &w3_wid, 1, &n_used); - else - bprob = 0; - /* Add in this link's acoustic score, which was a constant - factor in previous computations (if any). */ - link->alpha += (link->ascr << SENSCR_SHIFT) * ascale; - - if (w2_is_fil) { - w2_is_fil = w3_is_fil; - w3_is_fil = TRUE; - w2_wid = w3_wid; - while (prev_link->best_prev != NULL) { - prev_link = prev_link->best_prev; - w3_wid = prev_link->from->basewid; - if (!dict_filler_word(ps_search_dict(search), w3_wid) || prev_link->from == dag->start) { - w3_is_fil = FALSE; - break; - } - } - } - - /* Update scores for all paths exiting link->to. */ - for (x = link->to->exits; x; x = x->next) { - int32 score; - int32 w1_wid; - int16 w1_is_fil; - - w1_wid = x->link->to->basewid; - w1_is_fil = dict_filler_word(ps_search_dict(search), w1_wid) && x->link->to != dag->end; - - /* Update alpha with sum of previous alphas. */ - x->link->alpha = logmath_add(lmath, x->link->alpha, link->alpha + bprob); - - /* Update link score with maximum link score. */ - score = link->path_scr + x->link->ascr; - /* Calculate language score for bestpath if possible */ - if (lmset && !w1_is_fil && !w2_is_fil) { - if (w3_is_fil) - //partial context available - score += (ngram_bg_score(lmset, w1_wid, w2_wid, &n_used) >> SENSCR_SHIFT) * lwf; - else - //full context available - score += (ngram_tg_score(lmset, w1_wid, w2_wid, w3_wid, &n_used) >> SENSCR_SHIFT) * lwf; - } - - if (score BETTER_THAN x->link->path_scr) { - x->link->path_scr = score; - x->link->best_prev = link; - } - } - } - - /* Find best link entering final node, and calculate normalizer - * for posterior probabilities. */ - bestend = NULL; - bestescr = MAX_NEG_INT32; - - /* Normalizer is the alpha for the imaginary link exiting the - final node. */ - dag->norm = logmath_get_zero(lmath); - for (x = dag->end->entries; x; x = x->next) { - int32 bprob, n_used; - int32 from_wid; - int16 from_is_fil; - - from_wid = x->link->from->basewid; - from_is_fil = dict_filler_word(ps_search_dict(search), from_wid) && x->link->from != dag->start; - if (from_is_fil) { - ps_latlink_t *prev_link = x->link; - while (prev_link->best_prev != NULL) { - prev_link = prev_link->best_prev; - from_wid = prev_link->from->basewid; - if (!dict_filler_word(ps_search_dict(search), from_wid) || prev_link->from == dag->start) { - from_is_fil = FALSE; - break; - } - } - } - - if (lmset && !from_is_fil) - bprob = ngram_ng_prob(lmset, - x->link->to->basewid, - &from_wid, 1, &n_used); - else - bprob = 0; - dag->norm = logmath_add(lmath, dag->norm, x->link->alpha + bprob); - if (x->link->path_scr BETTER_THAN bestescr) { - bestescr = x->link->path_scr; - bestend = x->link; - } - } - /* FIXME: floating point... */ - dag->norm += (int32)(dag->final_node_ascr << SENSCR_SHIFT) * ascale; - - E_INFO("Bestpath score: %d\n", bestescr); - E_INFO("Normalizer P(O) = alpha(%s:%d:%d) = %d\n", - dict_wordstr(dag->search->dict, dag->end->wid), - dag->end->sf, dag->end->lef, - dag->norm); - return bestend; -} - -static int32 -ps_lattice_joint(ps_lattice_t *dag, ps_latlink_t *link, float32 ascale) -{ - ngram_model_t *lmset; - int32 jprob; - - /* Sort of a hack... */ - if (dag->search && 0 == strcmp(ps_search_name(dag->search), PS_SEARCH_NGRAM)) - lmset = ((ngram_search_t *)dag->search)->lmset; - else - lmset = NULL; - - jprob = (dag->final_node_ascr << SENSCR_SHIFT) * ascale; - while (link) { - if (lmset) { - int lback; - int32 from_wid, to_wid; - int16 from_is_fil, to_is_fil; - - from_wid = link->from->basewid; - to_wid = link->to->basewid; - from_is_fil = dict_filler_word(dag->dict, from_wid) && link->from != dag->start; - to_is_fil = dict_filler_word(dag->dict, to_wid) && link->to != dag->end; - - /* Find word predecessor if from-word is filler */ - if (!to_is_fil && from_is_fil) { - ps_latlink_t *prev_link = link; - while (prev_link->best_prev != NULL) { - prev_link = prev_link->best_prev; - from_wid = prev_link->from->basewid; - if (!dict_filler_word(dag->dict, from_wid) || prev_link->from == dag->start) { - from_is_fil = FALSE; - break; - } - } - } - - /* Compute unscaled language model probability. Note that - this is actually not the language model probability - that corresponds to this link, but that is okay, - because we are just taking the sum over all links in - the best path. */ - if (!from_is_fil && !to_is_fil) - jprob += ngram_ng_prob(lmset, to_wid, - &from_wid, 1, &lback); - } - /* If there is no language model, we assume that the language - model probability (such as it is) has been included in the - link score. */ - jprob += (link->ascr << SENSCR_SHIFT) * ascale; - link = link->best_prev; - } - - E_INFO("Joint P(O,S) = %d P(S|O) = %d\n", jprob, jprob - dag->norm); - return jprob; -} - -int32 -ps_lattice_posterior(ps_lattice_t *dag, ngram_model_t *lmset, - float32 ascale) -{ - logmath_t *lmath; - ps_latnode_t *node; - ps_latlink_t *link; - latlink_list_t *x; - ps_latlink_t *bestend; - int32 bestescr; - - lmath = dag->lmath; - - /* Reset all betas to zero. */ - for (node = dag->nodes; node; node = node->next) { - for (x = node->exits; x; x = x->next) { - x->link->beta = logmath_get_zero(lmath); - } - } - - bestend = NULL; - bestescr = MAX_NEG_INT32; - /* Accumulate backward probabilities for all links. */ - for (link = ps_lattice_reverse_edges(dag, NULL, NULL); - link; link = ps_lattice_reverse_next(dag, NULL)) { - int32 bprob, n_used; - int32 from_wid, to_wid; - int16 from_is_fil, to_is_fil; - - from_wid = link->from->basewid; - to_wid = link->to->basewid; - from_is_fil = dict_filler_word(dag->dict, from_wid) && link->from != dag->start; - to_is_fil = dict_filler_word(dag->dict, to_wid) && link->to != dag->end; - - /* Find word predecessor if from-word is filler */ - if (!to_is_fil && from_is_fil) { - ps_latlink_t *prev_link = link; - while (prev_link->best_prev != NULL) { - prev_link = prev_link->best_prev; - from_wid = prev_link->from->basewid; - if (!dict_filler_word(dag->dict, from_wid) || prev_link->from == dag->start) { - from_is_fil = FALSE; - break; - } - } - } - - /* Calculate LM probability. */ - if (lmset && !from_is_fil && !to_is_fil) - bprob = ngram_ng_prob(lmset, to_wid, &from_wid, 1, &n_used); - else - bprob = 0; - - if (link->to == dag->end) { - /* Track the best path - we will backtrace in order to - calculate the unscaled joint probability for sentence - posterior. */ - if (link->path_scr BETTER_THAN bestescr) { - bestescr = link->path_scr; - bestend = link; - } - /* Imaginary exit link from final node has beta = 1.0 */ - link->beta = bprob + (dag->final_node_ascr << SENSCR_SHIFT) * ascale; - } - else { - /* Update beta from all outgoing betas. */ - for (x = link->to->exits; x; x = x->next) { - link->beta = logmath_add(lmath, link->beta, - x->link->beta + bprob - + (x->link->ascr << SENSCR_SHIFT) * ascale); - } - } - } - - /* Return P(S|O) = P(O,S)/P(O) */ - return ps_lattice_joint(dag, bestend, ascale) - dag->norm; -} - -int32 -ps_lattice_posterior_prune(ps_lattice_t *dag, int32 beam) -{ - ps_latlink_t *link; - int npruned = 0; - - for (link = ps_lattice_traverse_edges(dag, dag->start, dag->end); - link; link = ps_lattice_traverse_next(dag, dag->end)) { - link->from->reachable = FALSE; - if (link->alpha + link->beta - dag->norm < beam) { - latlink_list_t *x, *tmp, *next; - tmp = NULL; - for (x = link->from->exits; x; x = next) { - next = x->next; - if (x->link == link) { - listelem_free(dag->latlink_list_alloc, x); - } - else { - x->next = tmp; - tmp = x; - } - } - link->from->exits = tmp; - tmp = NULL; - for (x = link->to->entries; x; x = next) { - next = x->next; - if (x->link == link) { - listelem_free(dag->latlink_list_alloc, x); - } - else { - x->next = tmp; - tmp = x; - } - } - link->to->entries = tmp; - listelem_free(dag->latlink_alloc, link); - ++npruned; - } - } - dag_mark_reachable(dag->end); - ps_lattice_delete_unreachable(dag); - return npruned; -} - - -/* Parameters to prune n-best alternatives search */ -#define MAX_PATHS 500 /* Max allowed active paths at any time */ -#define MAX_HYP_TRIES 10000 - -/* - * For each node in any path between from and end of utt, find the - * best score from "from".sf to end of utt. (NOTE: Uses bigram probs; - * this is an estimate of the best score from "from".) (NOTE #2: yes, - * this is the "heuristic score" used in A* search) - */ -static int32 -best_rem_score(ps_astar_t *nbest, ps_latnode_t * from) -{ - latlink_list_t *x; - int32 bestscore, score; - - if (from->info.rem_score <= 0) - return (from->info.rem_score); - - /* Best score from "from" to end of utt not known; compute from successors */ - bestscore = WORST_SCORE; - for (x = from->exits; x; x = x->next) { - int32 n_used; - - score = best_rem_score(nbest, x->link->to); - score += x->link->ascr; - if (nbest->lmset) - score += (ngram_bg_score(nbest->lmset, x->link->to->basewid, - from->basewid, &n_used) >> SENSCR_SHIFT) - * nbest->lwf; - if (score BETTER_THAN bestscore) - bestscore = score; - } - from->info.rem_score = bestscore; - - return bestscore; -} - -/* - * Insert newpath in sorted (by path score) list of paths. But if newpath is - * too far down the list, drop it (FIXME: necessary?) - * total_score = path score (newpath) + rem_score to end of utt. - */ -static void -path_insert(ps_astar_t *nbest, ps_latpath_t *newpath, int32 total_score) -{ - ps_latpath_t *prev, *p; - int32 i; - - prev = NULL; - for (i = 0, p = nbest->path_list; (i < MAX_PATHS) && p; p = p->next, i++) { - if ((p->score + p->node->info.rem_score) < total_score) - break; - prev = p; - } - - /* newpath should be inserted between prev and p */ - if (i < MAX_PATHS) { - /* Insert new partial hyp */ - newpath->next = p; - if (!prev) - nbest->path_list = newpath; - else - prev->next = newpath; - if (!p) - nbest->path_tail = newpath; - - nbest->n_path++; - nbest->n_hyp_insert++; - nbest->insert_depth += i; - } - else { - /* newpath score too low; reject it and also prune paths beyond MAX_PATHS */ - nbest->path_tail = prev; - prev->next = NULL; - nbest->n_path = MAX_PATHS; - listelem_free(nbest->latpath_alloc, newpath); - - nbest->n_hyp_reject++; - for (; p; p = newpath) { - newpath = p->next; - listelem_free(nbest->latpath_alloc, p); - nbest->n_hyp_reject++; - } - } -} - -/* Find all possible extensions to given partial path */ -static void -path_extend(ps_astar_t *nbest, ps_latpath_t * path) -{ - latlink_list_t *x; - ps_latpath_t *newpath; - int32 total_score, tail_score; - - /* Consider all successors of path->node */ - for (x = path->node->exits; x; x = x->next) { - int32 n_used; - - /* Skip successor if no path from it reaches the final node */ - if (x->link->to->info.rem_score <= WORST_SCORE) - continue; - - /* Create path extension and compute exact score for this extension */ - newpath = listelem_malloc(nbest->latpath_alloc); - newpath->node = x->link->to; - newpath->parent = path; - newpath->score = path->score + x->link->ascr; - if (nbest->lmset) { - if (path->parent) { - newpath->score += nbest->lwf - * (ngram_tg_score(nbest->lmset, newpath->node->basewid, - path->node->basewid, - path->parent->node->basewid, &n_used) - >> SENSCR_SHIFT); - } - else - newpath->score += nbest->lwf - * (ngram_bg_score(nbest->lmset, newpath->node->basewid, - path->node->basewid, &n_used) - >> SENSCR_SHIFT); - } - - /* Insert new partial path hypothesis into sorted path_list */ - nbest->n_hyp_tried++; - total_score = newpath->score + newpath->node->info.rem_score; - - /* First see if hyp would be worse than the worst */ - if (nbest->n_path >= MAX_PATHS) { - tail_score = - nbest->path_tail->score - + nbest->path_tail->node->info.rem_score; - if (total_score < tail_score) { - listelem_free(nbest->latpath_alloc, newpath); - nbest->n_hyp_reject++; - continue; - } - } - - path_insert(nbest, newpath, total_score); - } -} - -ps_astar_t * -ps_astar_start(ps_lattice_t *dag, - ngram_model_t *lmset, - float32 lwf, - int sf, int ef, - int w1, int w2) -{ - ps_astar_t *nbest; - ps_latnode_t *node; - - nbest = ckd_calloc(1, sizeof(*nbest)); - nbest->dag = dag; - nbest->lmset = lmset; - nbest->lwf = lwf; - nbest->sf = sf; - if (ef < 0) - nbest->ef = dag->n_frames + 1; - else - nbest->ef = ef; - nbest->w1 = w1; - nbest->w2 = w2; - nbest->latpath_alloc = listelem_alloc_init(sizeof(ps_latpath_t)); - - /* Initialize rem_score (A* heuristic) to default values */ - for (node = dag->nodes; node; node = node->next) { - if (node == dag->end) - node->info.rem_score = 0; - else if (node->exits == NULL) - node->info.rem_score = WORST_SCORE; - else - node->info.rem_score = 1; /* +ve => unknown value */ - } - - /* Create initial partial hypotheses list consisting of nodes starting at sf */ - nbest->path_list = nbest->path_tail = NULL; - for (node = dag->nodes; node; node = node->next) { - if (node->sf == sf) { - ps_latpath_t *path; - int32 n_used; - - best_rem_score(nbest, node); - path = listelem_malloc(nbest->latpath_alloc); - path->node = node; - path->parent = NULL; - if (nbest->lmset) - path->score = nbest->lwf * - ((w1 < 0) - ? ngram_bg_score(nbest->lmset, node->basewid, w2, &n_used) - : ngram_tg_score(nbest->lmset, node->basewid, w2, w1, &n_used)); - else - path->score = 0; - path->score >>= SENSCR_SHIFT; - path_insert(nbest, path, path->score + node->info.rem_score); - } - } - - return nbest; -} - -ps_latpath_t * -ps_astar_next(ps_astar_t *nbest) -{ - ps_lattice_t *dag; - - dag = nbest->dag; - - /* Pop the top (best) partial hypothesis */ - while ((nbest->top = nbest->path_list) != NULL) { - nbest->path_list = nbest->path_list->next; - if (nbest->top == nbest->path_tail) - nbest->path_tail = NULL; - nbest->n_path--; - - /* Complete hypothesis? */ - if ((nbest->top->node->sf >= nbest->ef) - || ((nbest->top->node == dag->end) && - (nbest->ef > dag->end->sf))) { - /* FIXME: Verify that it is non-empty. Also we may want - * to verify that it is actually distinct from other - * paths, since often this is not the case*/ - return nbest->top; - } - else { - if (nbest->top->node->fef < nbest->ef) - path_extend(nbest, nbest->top); - } - } - - /* Did not find any more paths to extend. */ - return NULL; -} - -char const * -ps_astar_hyp(ps_astar_t *nbest, ps_latpath_t *path) -{ - ps_search_t *search; - ps_latpath_t *p; - size_t len; - char *c; - char *hyp; - - search = nbest->dag->search; - - /* Backtrace once to get hypothesis length. */ - len = 0; - for (p = path; p; p = p->parent) { - if (dict_real_word(ps_search_dict(search), p->node->basewid)) { - char *wstr = dict_wordstr(ps_search_dict(search), p->node->basewid); - if (wstr != NULL) - len += strlen(wstr) + 1; - } - } - - if (len == 0) { - return NULL; - } - - /* Backtrace again to construct hypothesis string. */ - hyp = ckd_calloc(1, len); - c = hyp + len - 1; - for (p = path; p; p = p->parent) { - if (dict_real_word(ps_search_dict(search), p->node->basewid)) { - char *wstr = dict_wordstr(ps_search_dict(search), p->node->basewid); - if (wstr != NULL) { - len = strlen(wstr); - c -= len; - memcpy(c, wstr, len); - if (c > hyp) { - --c; - *c = ' '; - } - } - } - } - - nbest->hyps = glist_add_ptr(nbest->hyps, hyp); - return hyp; -} - -static void -ps_astar_node2itor(astar_seg_t *itor) -{ - ps_seg_t *seg = (ps_seg_t *)itor; - ps_latnode_t *node; - - assert(itor->cur < itor->n_nodes); - node = itor->nodes[itor->cur]; - if (itor->cur == itor->n_nodes - 1) - seg->ef = node->lef; - else - seg->ef = itor->nodes[itor->cur + 1]->sf - 1; - seg->word = dict_wordstr(ps_search_dict(seg->search), node->wid); - seg->sf = node->sf; - seg->prob = 0; /* FIXME: implement forward-backward */ -} - -static void -ps_astar_seg_free(ps_seg_t *seg) -{ - astar_seg_t *itor = (astar_seg_t *)seg; - ckd_free(itor->nodes); - ckd_free(itor); -} - -static ps_seg_t * -ps_astar_seg_next(ps_seg_t *seg) -{ - astar_seg_t *itor = (astar_seg_t *)seg; - - ++itor->cur; - if (itor->cur == itor->n_nodes) { - ps_astar_seg_free(seg); - return NULL; - } - else { - ps_astar_node2itor(itor); - } - - return seg; -} - -static ps_segfuncs_t ps_astar_segfuncs = { - /* seg_next */ ps_astar_seg_next, - /* seg_free */ ps_astar_seg_free -}; - -ps_seg_t * -ps_astar_seg_iter(ps_astar_t *astar, ps_latpath_t *path, float32 lwf) -{ - astar_seg_t *itor; - ps_latpath_t *p; - int cur; - - /* Backtrace and make an iterator, this should look familiar by now. */ - itor = ckd_calloc(1, sizeof(*itor)); - itor->base.vt = &ps_astar_segfuncs; - itor->base.search = astar->dag->search; - itor->base.lwf = lwf; - itor->n_nodes = itor->cur = 0; - for (p = path; p; p = p->parent) { - ++itor->n_nodes; - } - itor->nodes = ckd_calloc(itor->n_nodes, sizeof(*itor->nodes)); - cur = itor->n_nodes - 1; - for (p = path; p; p = p->parent) { - itor->nodes[cur] = p->node; - --cur; - } - - ps_astar_node2itor(itor); - return (ps_seg_t *)itor; -} - -void -ps_astar_finish(ps_astar_t *nbest) -{ - gnode_t *gn; - - /* Free all hyps. */ - for (gn = nbest->hyps; gn; gn = gnode_next(gn)) { - ckd_free(gnode_ptr(gn)); - } - glist_free(nbest->hyps); - /* Free all paths. */ - listelem_alloc_free(nbest->latpath_alloc); - /* Free the Henge. */ - ckd_free(nbest); -} - |