PocketSphinx  5prealpha
phone_loop_search.c
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37 
42 #include <sphinxbase/err.h>
43 
44 #include "phone_loop_search.h"
45 
46 static int phone_loop_search_start(ps_search_t *search);
47 static int phone_loop_search_step(ps_search_t *search, int frame_idx);
48 static int phone_loop_search_finish(ps_search_t *search);
49 static int phone_loop_search_reinit(ps_search_t *search, dict_t *dict, dict2pid_t *d2p);
50 static void phone_loop_search_free(ps_search_t *search);
51 static char const *phone_loop_search_hyp(ps_search_t *search, int32 *out_score);
52 static int32 phone_loop_search_prob(ps_search_t *search);
53 static ps_seg_t *phone_loop_search_seg_iter(ps_search_t *search);
54 
55 static ps_searchfuncs_t phone_loop_search_funcs = {
56  /* start: */ phone_loop_search_start,
57  /* step: */ phone_loop_search_step,
58  /* finish: */ phone_loop_search_finish,
59  /* reinit: */ phone_loop_search_reinit,
60  /* free: */ phone_loop_search_free,
61  /* lattice: */ NULL,
62  /* hyp: */ phone_loop_search_hyp,
63  /* prob: */ phone_loop_search_prob,
64  /* seg_iter: */ phone_loop_search_seg_iter,
65 };
66 
67 static int
68 phone_loop_search_reinit(ps_search_t *search, dict_t *dict, dict2pid_t *d2p)
69 {
71  cmd_ln_t *config = ps_search_config(search);
72  acmod_t *acmod = ps_search_acmod(search);
73  int i;
74 
75  /* Free old dict2pid, dict, if necessary. */
76  ps_search_base_reinit(search, dict, d2p);
77 
78  /* Initialize HMM context. */
79  if (pls->hmmctx)
81  pls->hmmctx = hmm_context_init(bin_mdef_n_emit_state(acmod->mdef),
82  acmod->tmat->tp, NULL, acmod->mdef->sseq);
83  if (pls->hmmctx == NULL)
84  return -1;
85 
86  /* Initialize penalty storage */
87  pls->n_phones = bin_mdef_n_ciphone(acmod->mdef);
88  pls->window = cmd_ln_int32_r(config, "-pl_window");
89  if (pls->penalties)
90  ckd_free(pls->penalties);
91  pls->penalties = (int32 *)ckd_calloc(pls->n_phones, sizeof(*pls->penalties));
92  if (pls->pen_buf)
93  ckd_free_2d(pls->pen_buf);
94  pls->pen_buf = (int32 **)ckd_calloc_2d(pls->window, pls->n_phones, sizeof(**pls->pen_buf));
95 
96  /* Initialize phone HMMs. */
97  if (pls->hmms) {
98  for (i = 0; i < pls->n_phones; ++i)
99  hmm_deinit((hmm_t *)&pls->hmms[i]);
100  ckd_free(pls->hmms);
101  }
102  pls->hmms = (hmm_t *)ckd_calloc(pls->n_phones, sizeof(*pls->hmms));
103  for (i = 0; i < pls->n_phones; ++i) {
104  hmm_init(pls->hmmctx, (hmm_t *)&pls->hmms[i],
105  FALSE,
106  bin_mdef_pid2ssid(acmod->mdef, i),
107  bin_mdef_pid2tmatid(acmod->mdef, i));
108  }
109  pls->penalty_weight = cmd_ln_float64_r(config, "-pl_weight");
110  pls->beam = logmath_log(acmod->lmath, cmd_ln_float64_r(config, "-pl_beam")) >> SENSCR_SHIFT;
111  pls->pbeam = logmath_log(acmod->lmath, cmd_ln_float64_r(config, "-pl_pbeam")) >> SENSCR_SHIFT;
112  pls->pip = logmath_log(acmod->lmath, cmd_ln_float32_r(config, "-pl_pip")) >> SENSCR_SHIFT;
113  E_INFO("State beam %d Phone exit beam %d Insertion penalty %d\n",
114  pls->beam, pls->pbeam, pls->pip);
115 
116  return 0;
117 }
118 
119 ps_search_t *
120 phone_loop_search_init(cmd_ln_t *config,
121  acmod_t *acmod,
122  dict_t *dict)
123 {
124  phone_loop_search_t *pls;
125 
126  /* Allocate and initialize. */
127  pls = (phone_loop_search_t *)ckd_calloc(1, sizeof(*pls));
128  ps_search_init(ps_search_base(pls), &phone_loop_search_funcs,
129  PS_SEARCH_TYPE_PHONE_LOOP, PS_DEFAULT_PL_SEARCH,
130  config, acmod, dict, NULL);
131  phone_loop_search_reinit(ps_search_base(pls), ps_search_dict(pls),
132  ps_search_dict2pid(pls));
133 
134  return ps_search_base(pls);
135 }
136 
137 static void
138 phone_loop_search_free_renorm(phone_loop_search_t *pls)
139 {
140  gnode_t *gn;
141  for (gn = pls->renorm; gn; gn = gnode_next(gn))
142  ckd_free(gnode_ptr(gn));
143  glist_free(pls->renorm);
144  pls->renorm = NULL;
145 }
146 
147 static void
148 phone_loop_search_free(ps_search_t *search)
149 {
150  phone_loop_search_t *pls = (phone_loop_search_t *)search;
151  int i;
152 
153  ps_search_base_free(search);
154  for (i = 0; i < pls->n_phones; ++i)
155  hmm_deinit((hmm_t *)&pls->hmms[i]);
156  phone_loop_search_free_renorm(pls);
157  ckd_free_2d(pls->pen_buf);
158  ckd_free(pls->hmms);
159  ckd_free(pls->penalties);
160  hmm_context_free(pls->hmmctx);
161  ckd_free(pls);
162 }
163 
164 static int
165 phone_loop_search_start(ps_search_t *search)
166 {
167  phone_loop_search_t *pls = (phone_loop_search_t *)search;
168  int i;
169 
170  /* Reset and enter all phone HMMs. */
171  for (i = 0; i < pls->n_phones; ++i) {
172  hmm_t *hmm = (hmm_t *)&pls->hmms[i];
173  hmm_clear(hmm);
174  hmm_enter(hmm, 0, -1, 0);
175  }
176  memset(pls->penalties, 0, pls->n_phones * sizeof(*pls->penalties));
177  for (i = 0; i < pls->window; i++)
178  memset(pls->pen_buf[i], 0, pls->n_phones * sizeof(*pls->pen_buf[i]));
179  phone_loop_search_free_renorm(pls);
180  pls->best_score = 0;
181  pls->pen_buf_ptr = 0;
182 
183  return 0;
184 }
185 
186 static void
187 renormalize_hmms(phone_loop_search_t *pls, int frame_idx, int32 norm)
188 {
189  phone_loop_renorm_t *rn = (phone_loop_renorm_t *)ckd_calloc(1, sizeof(*rn));
190  int i;
191 
192  pls->renorm = glist_add_ptr(pls->renorm, rn);
193  rn->frame_idx = frame_idx;
194  rn->norm = norm;
195 
196  for (i = 0; i < pls->n_phones; ++i) {
197  hmm_normalize((hmm_t *)&pls->hmms[i], norm);
198  }
199 }
200 
201 static void
202 evaluate_hmms(phone_loop_search_t *pls, int16 const *senscr, int frame_idx)
203 {
204  int32 bs = WORST_SCORE;
205  int i;
206 
207  hmm_context_set_senscore(pls->hmmctx, senscr);
208 
209  for (i = 0; i < pls->n_phones; ++i) {
210  hmm_t *hmm = (hmm_t *)&pls->hmms[i];
211  int32 score;
212 
213  if (hmm_frame(hmm) < frame_idx)
214  continue;
215  score = hmm_vit_eval(hmm);
216  if (score BETTER_THAN bs) {
217  bs = score;
218  }
219  }
220  pls->best_score = bs;
221 }
222 
223 static void
224 store_scores(phone_loop_search_t *pls, int frame_idx)
225 {
226  int i, j, itr;
227 
228  for (i = 0; i < pls->n_phones; ++i) {
229  hmm_t *hmm = (hmm_t *)&pls->hmms[i];
230  pls->pen_buf[pls->pen_buf_ptr][i] = (hmm_bestscore(hmm) - pls->best_score) * pls->penalty_weight;
231  }
232  pls->pen_buf_ptr++;
233  pls->pen_buf_ptr = pls->pen_buf_ptr % pls->window;
234 
235  /* update penalties */
236  for (i = 0; i < pls->n_phones; ++i) {
237  pls->penalties[i] = WORST_SCORE;
238  for (j = 0, itr = pls->pen_buf_ptr + 1; j < pls->window; j++, itr++) {
239  itr = itr % pls->window;
240  if (pls->pen_buf[itr][i] > pls->penalties[i])
241  pls->penalties[i] = pls->pen_buf[itr][i];
242  }
243  }
244 }
245 
246 static void
247 prune_hmms(phone_loop_search_t *pls, int frame_idx)
248 {
249  int32 thresh = pls->best_score + pls->beam;
250  int nf = frame_idx + 1;
251  int i;
252 
253  /* Check all phones to see if they remain active in the next frame. */
254  for (i = 0; i < pls->n_phones; ++i) {
255  hmm_t *hmm = (hmm_t *)&pls->hmms[i];
256 
257  if (hmm_frame(hmm) < frame_idx)
258  continue;
259  /* Retain if score better than threshold. */
260  if (hmm_bestscore(hmm) BETTER_THAN thresh) {
261  hmm_frame(hmm) = nf;
262  }
263  else
264  hmm_clear_scores(hmm);
265  }
266 }
267 
268 static void
269 phone_transition(phone_loop_search_t *pls, int frame_idx)
270 {
271  int32 thresh = pls->best_score + pls->pbeam;
272  int nf = frame_idx + 1;
273  int i;
274 
275  /* Now transition out of phones whose last states are inside the
276  * phone transition beam. */
277  for (i = 0; i < pls->n_phones; ++i) {
278  hmm_t *hmm = (hmm_t *)&pls->hmms[i];
279  int32 newphone_score;
280  int j;
281 
282  if (hmm_frame(hmm) != nf)
283  continue;
284 
285  newphone_score = hmm_out_score(hmm) + pls->pip;
286  if (newphone_score BETTER_THAN thresh) {
287  /* Transition into all phones using the usual Viterbi rule. */
288  for (j = 0; j < pls->n_phones; ++j) {
289  hmm_t *nhmm = (hmm_t *)&pls->hmms[j];
290 
291  if (hmm_frame(nhmm) < frame_idx
292  || newphone_score BETTER_THAN hmm_in_score(nhmm)) {
293  hmm_enter(nhmm, newphone_score, hmm_out_history(hmm), nf);
294  }
295  }
296  }
297  }
298 }
299 
300 static int
301 phone_loop_search_step(ps_search_t *search, int frame_idx)
302 {
303  phone_loop_search_t *pls = (phone_loop_search_t *)search;
304  acmod_t *acmod = ps_search_acmod(search);
305  int16 const *senscr;
306  int i;
307 
308  /* All CI senones are active all the time. */
309  if (!ps_search_acmod(pls)->compallsen) {
310  acmod_clear_active(ps_search_acmod(pls));
311  for (i = 0; i < pls->n_phones; ++i)
312  acmod_activate_hmm(acmod, (hmm_t *)&pls->hmms[i]);
313  }
314 
315  /* Calculate senone scores for current frame. */
316  senscr = acmod_score(acmod, &frame_idx);
317 
318  /* Renormalize, if necessary. */
319  if (pls->best_score + (2 * pls->beam) WORSE_THAN WORST_SCORE) {
320  E_INFO("Renormalizing Scores at frame %d, best score %d\n",
321  frame_idx, pls->best_score);
322  renormalize_hmms(pls, frame_idx, pls->best_score);
323  }
324 
325  /* Evaluate phone HMMs for current frame. */
326  evaluate_hmms(pls, senscr, frame_idx);
327 
328  /* Store hmm scores for senone penaly calculation */
329  store_scores(pls, frame_idx);
330 
331  /* Prune phone HMMs. */
332  prune_hmms(pls, frame_idx);
333 
334  /* Do phone transitions. */
335  phone_transition(pls, frame_idx);
336 
337  return 0;
338 }
339 
340 static int
341 phone_loop_search_finish(ps_search_t *search)
342 {
343  /* Actually nothing to do here really. */
344  return 0;
345 }
346 
347 static char const *
348 phone_loop_search_hyp(ps_search_t *search, int32 *out_score)
349 {
350  E_WARN("Hypotheses are not returned from phone loop search");
351  return NULL;
352 }
353 
354 static int32
355 phone_loop_search_prob(ps_search_t *search)
356 {
357  /* FIXME: Actually... they ought to be. */
358  E_WARN("Posterior probabilities are not returned from phone loop search");
359  return 0;
360 }
361 
362 static ps_seg_t *
363 phone_loop_search_seg_iter(ps_search_t *search)
364 {
365  E_WARN("Hypotheses are not returned from phone loop search");
366  return NULL;
367 }
int32 * penalties
Penalties for CI phones in current frame.
Base structure for search module.
void hmm_init(hmm_context_t *ctx, hmm_t *hmm, int mpx, int ssid, int tmatid)
Populate a previously-allocated HMM structure, allocating internal data.
Definition: hmm.c:89
int32 pbeam
Phone exit pruning beam width.
hmm_context_t * hmmctx
HMM context structure.
void ps_search_base_reinit(ps_search_t *search, dict_t *dict, dict2pid_t *d2p)
Re-initialize base structure with new dictionary.
An individual HMM among the HMM search space.
uint8 *** tp
The transition matrices; kept in the same scale as acoustic scores; tp[tmatid][from-state][to-state]...
Definition: tmat.h:56
logmath_t * lmath
Log-math computation.
Definition: acmod.h:151
uint16 ** sseq
Unique senone sequences (2D array built at load time)
Definition: bin_mdef.h:134
void hmm_deinit(hmm_t *hmm)
Free an HMM structure, releasing internal data (but not the HMM structure itself).
Definition: hmm.c:111
void acmod_activate_hmm(acmod_t *acmod, hmm_t *hmm)
Activate senones associated with an HMM.
Definition: acmod.c:1213
int32 ** pen_buf
Penalty buffer.
float64 penalty_weight
Weighting factor for penalties.
void ps_search_init(ps_search_t *search, ps_searchfuncs_t *vt, const char *type, const char *name, cmd_ln_t *config, acmod_t *acmod, dict_t *dict, dict2pid_t *d2p)
Initialize base structure.
int32 norm
Normalization constant.
int32 hmm_vit_eval(hmm_t *hmm)
Viterbi evaluation of given HMM.
Definition: hmm.c:789
void hmm_normalize(hmm_t *h, int32 bestscr)
Renormalize the scores in this HMM based on the given best score.
Definition: hmm.c:209
hmm_context_t * hmm_context_init(int32 n_emit_state, uint8 **const *tp, int16 const *senscore, uint16 *const *sseq)
Create an HMM context.
Definition: hmm.c:56
void ps_search_base_free(ps_search_t *search)
Free search.
int16 pen_buf_ptr
Pointer for frame to fill in penalty buffer.
#define WORST_SCORE
Large &quot;bad&quot; score.
Definition: hmm.h:84
tmat_t * tmat
Transition matrices.
Definition: acmod.h:160
void hmm_enter(hmm_t *h, int32 score, int32 histid, int frame)
Enter an HMM with the given path score and history ID.
Definition: hmm.c:201
void acmod_clear_active(acmod_t *acmod)
Clear set of active senones.
Definition: acmod.c:1197
#define hmm_context_set_senscore(ctx, senscr)
Change the senone score array for a context.
Definition: hmm.h:227
#define SENSCR_SHIFT
Shift count for senone scores.
Definition: hmm.h:73
a structure for a dictionary.
Definition: dict.h:76
#define WORSE_THAN
Is one score worse than another?
Definition: hmm.h:100
void hmm_clear(hmm_t *h)
Reset the states of the HMM to the invalid condition.
Definition: hmm.c:183
Fast and rough context-independent phoneme loop search.
int32 best_score
Best Viterbi score in current frame.
int window
Window size for phoneme lookahead.
hmm_t * hmms
Basic HMM structures for CI phones.
int32 beam
HMM pruning beam width.
#define BETTER_THAN
Is one score better than another?
Definition: hmm.h:95
void hmm_clear_scores(hmm_t *h)
Reset the scores of the HMM.
Definition: hmm.c:170
int32 pip
Phone insertion penalty (&quot;language score&quot;).
void hmm_context_free(hmm_context_t *ctx)
Free an HMM context.
Definition: hmm.c:80
bin_mdef_t * mdef
Model definition.
Definition: acmod.h:159
V-table for search algorithm.
Base structure for hypothesis segmentation iterator.
int frame_idx
Frame of renormalization.
Acoustic model structure.
Definition: acmod.h:148
Building composite triphone (as well as word internal triphones) with the dictionary.
Definition: dict2pid.h:84
int16 n_phones
Size of phone array.
Phone loop search structure.
glist_t renorm
List of renormalizations.
int16 const * acmod_score(acmod_t *acmod, int *inout_frame_idx)
Score one frame of data.
Definition: acmod.c:1106
Renormalization event.