SphinxBase 0.6
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00001 /* -*- c-basic-offset: 4; indent-tabs-mode: nil -*- */ 00002 /* ==================================================================== 00003 * Copyright (c) 1999-2007 Carnegie Mellon University. All rights 00004 * reserved. 00005 * 00006 * Redistribution and use in source and binary forms, with or without 00007 * modification, are permitted provided that the following conditions 00008 * are met: 00009 * 00010 * 1. Redistributions of source code must retain the above copyright 00011 * notice, this list of conditions and the following disclaimer. 00012 * 00013 * 2. Redistributions in binary form must reproduce the above copyright 00014 * notice, this list of conditions and the following disclaimer in 00015 * the documentation and/or other materials provided with the 00016 * distribution. 00017 * 00018 * This work was supported in part by funding from the Defense Advanced 00019 * Research Projects Agency and the National Science Foundation of the 00020 * United States of America, and the CMU Sphinx Speech Consortium. 00021 * 00022 * THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS'' AND 00023 * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 00024 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 00025 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY 00026 * NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 00027 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 00028 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 00029 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 00030 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 00031 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 00032 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 00033 * 00034 * ==================================================================== 00035 * 00036 */ 00037 /* 00038 * \file lm3g_templates.c Core Sphinx 3-gram code used in 00039 * DMP/DMP32/ARPA (for now) model code. 00040 */ 00041 00042 #include <assert.h> 00043 00044 /* Locate a specific bigram within a bigram list */ 00045 #define BINARY_SEARCH_THRESH 16 00046 static int32 00047 find_bg(bigram_t * bg, int32 n, int32 w) 00048 { 00049 int32 i, b, e; 00050 00051 /* Binary search until segment size < threshold */ 00052 b = 0; 00053 e = n; 00054 while (e - b > BINARY_SEARCH_THRESH) { 00055 i = (b + e) >> 1; 00056 if (bg[i].wid < w) 00057 b = i + 1; 00058 else if (bg[i].wid > w) 00059 e = i; 00060 else 00061 return i; 00062 } 00063 00064 /* Linear search within narrowed segment */ 00065 for (i = b; (i < e) && (bg[i].wid != w); i++); 00066 return ((i < e) ? i : -1); 00067 } 00068 00069 static int32 00070 lm3g_bg_score(NGRAM_MODEL_TYPE *model, 00071 int32 lw1, int32 lw2, int32 *n_used) 00072 { 00073 int32 i, n, b, score; 00074 bigram_t *bg; 00075 00076 if (lw1 < 0 || model->base.n < 2) { 00077 *n_used = 1; 00078 return model->lm3g.unigrams[lw2].prob1.l; 00079 } 00080 00081 b = FIRST_BG(model, lw1); 00082 n = FIRST_BG(model, lw1 + 1) - b; 00083 bg = model->lm3g.bigrams + b; 00084 00085 if ((i = find_bg(bg, n, lw2)) >= 0) { 00086 /* Access mode = bigram */ 00087 *n_used = 2; 00088 score = model->lm3g.prob2[bg[i].prob2].l; 00089 } 00090 else { 00091 /* Access mode = unigram */ 00092 *n_used = 1; 00093 score = model->lm3g.unigrams[lw1].bo_wt1.l + model->lm3g.unigrams[lw2].prob1.l; 00094 } 00095 00096 return (score); 00097 } 00098 00099 static void 00100 load_tginfo(NGRAM_MODEL_TYPE *model, int32 lw1, int32 lw2) 00101 { 00102 int32 i, n, b, t; 00103 bigram_t *bg; 00104 tginfo_t *tginfo; 00105 00106 /* First allocate space for tg information for bg lw1,lw2 */ 00107 tginfo = (tginfo_t *) listelem_malloc(model->lm3g.le); 00108 tginfo->w1 = lw1; 00109 tginfo->tg = NULL; 00110 tginfo->next = model->lm3g.tginfo[lw2]; 00111 model->lm3g.tginfo[lw2] = tginfo; 00112 00113 /* Locate bigram lw1,lw2 */ 00114 b = model->lm3g.unigrams[lw1].bigrams; 00115 n = model->lm3g.unigrams[lw1 + 1].bigrams - b; 00116 bg = model->lm3g.bigrams + b; 00117 00118 if ((n > 0) && ((i = find_bg(bg, n, lw2)) >= 0)) { 00119 tginfo->bowt = model->lm3g.bo_wt2[bg[i].bo_wt2].l; 00120 00121 /* Find t = Absolute first trigram index for bigram lw1,lw2 */ 00122 b += i; /* b = Absolute index of bigram lw1,lw2 on disk */ 00123 t = FIRST_TG(model, b); 00124 00125 tginfo->tg = model->lm3g.trigrams + t; 00126 00127 /* Find #tg for bigram w1,w2 */ 00128 tginfo->n_tg = FIRST_TG(model, b + 1) - t; 00129 } 00130 else { /* No bigram w1,w2 */ 00131 tginfo->bowt = 0; 00132 tginfo->n_tg = 0; 00133 } 00134 } 00135 00136 /* Similar to find_bg */ 00137 static int32 00138 find_tg(trigram_t * tg, int32 n, int32 w) 00139 { 00140 int32 i, b, e; 00141 00142 b = 0; 00143 e = n; 00144 while (e - b > BINARY_SEARCH_THRESH) { 00145 i = (b + e) >> 1; 00146 if (tg[i].wid < w) 00147 b = i + 1; 00148 else if (tg[i].wid > w) 00149 e = i; 00150 else 00151 return i; 00152 } 00153 00154 for (i = b; (i < e) && (tg[i].wid != w); i++); 00155 return ((i < e) ? i : -1); 00156 } 00157 00158 static int32 00159 lm3g_tg_score(NGRAM_MODEL_TYPE *model, int32 lw1, 00160 int32 lw2, int32 lw3, int32 *n_used) 00161 { 00162 ngram_model_t *base = &model->base; 00163 int32 i, n, score; 00164 trigram_t *tg; 00165 tginfo_t *tginfo, *prev_tginfo; 00166 00167 if ((base->n < 3) || (lw1 < 0) || (lw2 < 0)) 00168 return (lm3g_bg_score(model, lw2, lw3, n_used)); 00169 00170 prev_tginfo = NULL; 00171 for (tginfo = model->lm3g.tginfo[lw2]; tginfo; tginfo = tginfo->next) { 00172 if (tginfo->w1 == lw1) 00173 break; 00174 prev_tginfo = tginfo; 00175 } 00176 00177 if (!tginfo) { 00178 load_tginfo(model, lw1, lw2); 00179 tginfo = model->lm3g.tginfo[lw2]; 00180 } 00181 else if (prev_tginfo) { 00182 prev_tginfo->next = tginfo->next; 00183 tginfo->next = model->lm3g.tginfo[lw2]; 00184 model->lm3g.tginfo[lw2] = tginfo; 00185 } 00186 00187 tginfo->used = 1; 00188 00189 /* Trigrams for w1,w2 now pointed to by tginfo */ 00190 n = tginfo->n_tg; 00191 tg = tginfo->tg; 00192 if ((i = find_tg(tg, n, lw3)) >= 0) { 00193 /* Access mode = trigram */ 00194 *n_used = 3; 00195 score = model->lm3g.prob3[tg[i].prob3].l; 00196 } 00197 else { 00198 score = tginfo->bowt + lm3g_bg_score(model, lw2, lw3, n_used); 00199 } 00200 00201 return (score); 00202 } 00203 00204 static int32 00205 lm3g_template_score(ngram_model_t *base, int32 wid, 00206 int32 *history, int32 n_hist, 00207 int32 *n_used) 00208 { 00209 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base; 00210 switch (n_hist) { 00211 case 0: 00212 /* Access mode: unigram */ 00213 *n_used = 1; 00214 return model->lm3g.unigrams[wid].prob1.l; 00215 case 1: 00216 return lm3g_bg_score(model, history[0], wid, n_used); 00217 case 2: 00218 default: 00219 /* Anything greater than 2 is the same as a trigram for now. */ 00220 return lm3g_tg_score(model, history[1], history[0], wid, n_used); 00221 } 00222 } 00223 00224 static int32 00225 lm3g_template_raw_score(ngram_model_t *base, int32 wid, 00226 int32 *history, int32 n_hist, 00227 int32 *n_used) 00228 { 00229 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base; 00230 int32 score; 00231 00232 switch (n_hist) { 00233 case 0: 00234 /* Access mode: unigram */ 00235 *n_used = 1; 00236 /* Undo insertion penalty. */ 00237 score = model->lm3g.unigrams[wid].prob1.l - base->log_wip; 00238 /* Undo language weight. */ 00239 score = (int32)(score / base->lw); 00240 /* Undo unigram interpolation */ 00241 if (strcmp(base->word_str[wid], "<s>") != 0) { /* FIXME: configurable start_sym */ 00242 score = logmath_log(base->lmath, 00243 logmath_exp(base->lmath, score) 00244 - logmath_exp(base->lmath, 00245 base->log_uniform + base->log_uniform_weight)); 00246 } 00247 return score; 00248 case 1: 00249 score = lm3g_bg_score(model, history[0], wid, n_used); 00250 break; 00251 case 2: 00252 default: 00253 /* Anything greater than 2 is the same as a trigram for now. */ 00254 score = lm3g_tg_score(model, history[1], history[0], wid, n_used); 00255 break; 00256 } 00257 /* FIXME (maybe): This doesn't undo unigram weighting in backoff cases. */ 00258 return (int32)((score - base->log_wip) / base->lw); 00259 } 00260 00261 static int32 00262 lm3g_template_add_ug(ngram_model_t *base, 00263 int32 wid, int32 lweight) 00264 { 00265 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base; 00266 return lm3g_add_ug(base, &model->lm3g, wid, lweight); 00267 } 00268 00269 static void 00270 lm3g_template_flush(ngram_model_t *base) 00271 { 00272 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base; 00273 lm3g_tginfo_reset(base, &model->lm3g); 00274 } 00275 00276 typedef struct lm3g_iter_s { 00277 ngram_iter_t base; 00278 unigram_t *ug; 00279 bigram_t *bg; 00280 trigram_t *tg; 00281 } lm3g_iter_t; 00282 00283 static ngram_iter_t * 00284 lm3g_template_iter(ngram_model_t *base, int32 wid, 00285 int32 *history, int32 n_hist) 00286 { 00287 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base; 00288 lm3g_iter_t *itor = ckd_calloc(1, sizeof(*itor)); 00289 00290 ngram_iter_init((ngram_iter_t *)itor, base, n_hist, FALSE); 00291 00292 if (n_hist == 0) { 00293 /* Unigram is the easiest. */ 00294 itor->ug = model->lm3g.unigrams + wid; 00295 return (ngram_iter_t *)itor; 00296 } 00297 else if (n_hist == 1) { 00298 int32 i, n, b; 00299 /* Find the bigram, as in bg_score above (duplicate code...) */ 00300 itor->ug = model->lm3g.unigrams + history[0]; 00301 b = FIRST_BG(model, history[0]); 00302 n = FIRST_BG(model, history[0] + 1) - b; 00303 itor->bg = model->lm3g.bigrams + b; 00304 /* If no such bigram exists then fail. */ 00305 if ((i = find_bg(itor->bg, n, wid)) < 0) { 00306 ngram_iter_free((ngram_iter_t *)itor); 00307 return NULL; 00308 } 00309 itor->bg += i; 00310 return (ngram_iter_t *)itor; 00311 } 00312 else if (n_hist == 2) { 00313 int32 i, n; 00314 tginfo_t *tginfo, *prev_tginfo; 00315 /* Find the trigram, as in tg_score above (duplicate code...) */ 00316 itor->ug = model->lm3g.unigrams + history[1]; 00317 prev_tginfo = NULL; 00318 for (tginfo = model->lm3g.tginfo[history[0]]; 00319 tginfo; tginfo = tginfo->next) { 00320 if (tginfo->w1 == history[1]) 00321 break; 00322 prev_tginfo = tginfo; 00323 } 00324 00325 if (!tginfo) { 00326 load_tginfo(model, history[1], history[0]); 00327 tginfo = model->lm3g.tginfo[history[0]]; 00328 } 00329 else if (prev_tginfo) { 00330 prev_tginfo->next = tginfo->next; 00331 tginfo->next = model->lm3g.tginfo[history[0]]; 00332 model->lm3g.tginfo[history[0]] = tginfo; 00333 } 00334 00335 tginfo->used = 1; 00336 00337 /* Trigrams for w1,w2 now pointed to by tginfo */ 00338 n = tginfo->n_tg; 00339 itor->tg = tginfo->tg; 00340 if ((i = find_tg(itor->tg, n, wid)) >= 0) { 00341 itor->tg += i; 00342 /* Now advance the bigram pointer accordingly. FIXME: 00343 * Note that we actually already found the relevant bigram 00344 * in load_tginfo. */ 00345 itor->bg = model->lm3g.bigrams; 00346 while (FIRST_TG(model, (itor->bg - model->lm3g.bigrams + 1)) 00347 <= (itor->tg - model->lm3g.trigrams)) 00348 ++itor->bg; 00349 return (ngram_iter_t *)itor; 00350 } 00351 else { 00352 ngram_iter_free((ngram_iter_t *)itor); 00353 return (ngram_iter_t *)NULL; 00354 } 00355 } 00356 else { 00357 /* Should not happen. */ 00358 assert(n_hist == 0); /* Guaranteed to fail. */ 00359 ngram_iter_free((ngram_iter_t *)itor); 00360 return NULL; 00361 } 00362 } 00363 00364 static ngram_iter_t * 00365 lm3g_template_mgrams(ngram_model_t *base, int m) 00366 { 00367 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base; 00368 lm3g_iter_t *itor = ckd_calloc(1, sizeof(*itor)); 00369 ngram_iter_init((ngram_iter_t *)itor, base, m, FALSE); 00370 00371 itor->ug = model->lm3g.unigrams; 00372 itor->bg = model->lm3g.bigrams; 00373 itor->tg = model->lm3g.trigrams; 00374 00375 /* Advance bigram pointer to match first trigram. */ 00376 if (m > 1 && base->n_counts[1] > 1) { 00377 while (FIRST_TG(model, (itor->bg - model->lm3g.bigrams + 1)) 00378 <= (itor->tg - model->lm3g.trigrams)) 00379 ++itor->bg; 00380 } 00381 00382 /* Advance unigram pointer to match first bigram. */ 00383 if (m > 0 && base->n_counts[0] > 1) { 00384 while (itor->ug[1].bigrams <= (itor->bg - model->lm3g.bigrams)) 00385 ++itor->ug; 00386 } 00387 00388 return (ngram_iter_t *)itor; 00389 } 00390 00391 static ngram_iter_t * 00392 lm3g_template_successors(ngram_iter_t *bitor) 00393 { 00394 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)bitor->model; 00395 lm3g_iter_t *from = (lm3g_iter_t *)bitor; 00396 lm3g_iter_t *itor = ckd_calloc(1, sizeof(*itor)); 00397 00398 itor->ug = from->ug; 00399 switch (bitor->m) { 00400 case 0: 00401 /* Next itor bigrams is the same as this itor bigram or 00402 itor bigrams is more than total count. This means no successors */ 00403 if (((itor->ug + 1) - model->lm3g.unigrams < bitor->model->n_counts[0] && 00404 itor->ug->bigrams == (itor->ug + 1)->bigrams) || 00405 itor->ug->bigrams == bitor->model->n_counts[1]) 00406 goto done; 00407 00408 /* Start iterating from first bigram successor of from->ug. */ 00409 itor->bg = model->lm3g.bigrams + itor->ug->bigrams; 00410 break; 00411 case 1: 00412 itor->bg = from->bg; 00413 00414 /* This indicates no successors */ 00415 if (((itor->bg + 1) - model->lm3g.bigrams < bitor->model->n_counts[1] && 00416 FIRST_TG (model, itor->bg - model->lm3g.bigrams) == 00417 FIRST_TG (model, (itor->bg + 1) - model->lm3g.bigrams)) || 00418 FIRST_TG (model, itor->bg - model->lm3g.bigrams) == bitor->model->n_counts[2]) 00419 goto done; 00420 00421 /* Start iterating from first trigram successor of from->bg. */ 00422 itor->tg = (model->lm3g.trigrams 00423 + FIRST_TG(model, (itor->bg - model->lm3g.bigrams))); 00424 #if 0 00425 printf("%s %s => %d (%s)\n", 00426 model->base.word_str[itor->ug - model->lm3g.unigrams], 00427 model->base.word_str[itor->bg->wid], 00428 FIRST_TG(model, (itor->bg - model->lm3g.bigrams)), 00429 model->base.word_str[itor->tg->wid]); 00430 #endif 00431 break; 00432 case 2: 00433 default: 00434 /* All invalid! */ 00435 goto done; 00436 } 00437 00438 ngram_iter_init((ngram_iter_t *)itor, bitor->model, bitor->m + 1, TRUE); 00439 return (ngram_iter_t *)itor; 00440 done: 00441 ckd_free(itor); 00442 return NULL; 00443 } 00444 00445 static int32 const * 00446 lm3g_template_iter_get(ngram_iter_t *base, 00447 int32 *out_score, int32 *out_bowt) 00448 { 00449 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base->model; 00450 lm3g_iter_t *itor = (lm3g_iter_t *)base; 00451 00452 base->wids[0] = itor->ug - model->lm3g.unigrams; 00453 if (itor->bg) base->wids[1] = itor->bg->wid; 00454 if (itor->tg) base->wids[2] = itor->tg->wid; 00455 #if 0 00456 printf("itor_get: %d %d %d\n", base->wids[0], base->wids[1], base->wids[2]); 00457 #endif 00458 00459 switch (base->m) { 00460 case 0: 00461 *out_score = itor->ug->prob1.l; 00462 *out_bowt = itor->ug->bo_wt1.l; 00463 break; 00464 case 1: 00465 *out_score = model->lm3g.prob2[itor->bg->prob2].l; 00466 if (model->lm3g.bo_wt2) 00467 *out_bowt = model->lm3g.bo_wt2[itor->bg->bo_wt2].l; 00468 else 00469 *out_bowt = 0; 00470 break; 00471 case 2: 00472 *out_score = model->lm3g.prob3[itor->tg->prob3].l; 00473 *out_bowt = 0; 00474 break; 00475 default: /* Should not happen. */ 00476 return NULL; 00477 } 00478 return base->wids; 00479 } 00480 00481 static ngram_iter_t * 00482 lm3g_template_iter_next(ngram_iter_t *base) 00483 { 00484 NGRAM_MODEL_TYPE *model = (NGRAM_MODEL_TYPE *)base->model; 00485 lm3g_iter_t *itor = (lm3g_iter_t *)base; 00486 00487 switch (base->m) { 00488 case 0: 00489 ++itor->ug; 00490 /* Check for end condition. */ 00491 if (itor->ug - model->lm3g.unigrams >= base->model->n_counts[0]) 00492 goto done; 00493 break; 00494 case 1: 00495 ++itor->bg; 00496 /* Check for end condition. */ 00497 if (itor->bg - model->lm3g.bigrams >= base->model->n_counts[1]) 00498 goto done; 00499 /* Advance unigram pointer if necessary in order to get one 00500 * that points to this bigram. */ 00501 while (itor->bg - model->lm3g.bigrams >= itor->ug[1].bigrams) { 00502 /* Stop if this is a successor iterator, since we don't 00503 * want a new unigram. */ 00504 if (base->successor) 00505 goto done; 00506 ++itor->ug; 00507 if (itor->ug == model->lm3g.unigrams + base->model->n_counts[0]) { 00508 E_ERROR("Bigram %d has no valid unigram parent\n", 00509 itor->bg - model->lm3g.bigrams); 00510 goto done; 00511 } 00512 } 00513 break; 00514 case 2: 00515 ++itor->tg; 00516 /* Check for end condition. */ 00517 if (itor->tg - model->lm3g.trigrams >= base->model->n_counts[2]) 00518 goto done; 00519 /* Advance bigram pointer if necessary. */ 00520 while (itor->tg - model->lm3g.trigrams >= 00521 FIRST_TG(model, (itor->bg - model->lm3g.bigrams + 1))) { 00522 if (base->successor) 00523 goto done; 00524 ++itor->bg; 00525 if (itor->bg == model->lm3g.bigrams + base->model->n_counts[1]) { 00526 E_ERROR("Trigram %d has no valid bigram parent\n", 00527 itor->tg - model->lm3g.trigrams); 00528 00529 goto done; 00530 } 00531 } 00532 /* Advance unigram pointer if necessary. */ 00533 while (itor->bg - model->lm3g.bigrams >= itor->ug[1].bigrams) { 00534 ++itor->ug; 00535 if (itor->ug == model->lm3g.unigrams + base->model->n_counts[0]) { 00536 E_ERROR("Trigram %d has no valid unigram parent\n", 00537 itor->tg - model->lm3g.trigrams); 00538 goto done; 00539 } 00540 } 00541 break; 00542 default: /* Should not happen. */ 00543 goto done; 00544 } 00545 00546 return (ngram_iter_t *)itor; 00547 done: 00548 ngram_iter_free(base); 00549 return NULL; 00550 } 00551 00552 static void 00553 lm3g_template_iter_free(ngram_iter_t *base) 00554 { 00555 ckd_free(base); 00556 }