libsent/src/phmm/mkwhmm.c

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/*
 * Copyright (c) 1991-2011 Kawahara Lab., Kyoto University
 * Copyright (c) 2000-2005 Shikano Lab., Nara Institute of Science and Technology
 * Copyright (c) 2005-2011 Julius project team, Nagoya Institute of Technology
 * All rights reserved
 */

/* When not a multi-path mode, initial & accept arc will be stripped and
   trans prob to accept state will be stored in accept_ac_a. */

#include <sent/stddefs.h>
#include <sent/hmm.h>

static int
totalstatelen(HMM_Logical **hdseq, int hdseqlen, boolean *has_sp, HTK_HMM_INFO *hmminfo)
{
  int i, len;

  len = 0;
  for (i=0;i<hdseqlen;i++) {
    len += hmm_logical_state_num(hdseq[i]) - 2;
    if (has_sp) {
      if (has_sp[i]) {
        len += hmm_logical_state_num(hmminfo->sp) - 2;
      }
    }
  }
  if (hmminfo->multipath) {
    /* add count for the initial and final state */
    len += 2;
  }
  return(len);
}

static void
add_arc(HMM_STATE *state, int arc, LOGPROB a)
{
  A_CELL *atmp;

  atmp = (A_CELL *)mymalloc(sizeof(A_CELL));
  atmp->a = a;
  atmp->arc = arc;
  atmp->next = state->ac;
  state->ac = atmp;
}

/* make word(phrase) HMM from HTK_HMM_INFO */
/* LM prob will be assigned for cross-word arcs */
/* new HMM is malloced and returned */

HMM *
new_make_word_hmm_with_lm(HTK_HMM_INFO *hmminfo, HMM_Logical **hdseq, int hdseqlen, boolean *has_sp, LOGPROB *lscore)
{
  HMM *new;
  int i,j,n;
  int afrom, ato;
  LOGPROB logprob;
  HTK_HMM_Trans *tr;
  int state_num;

  if (has_sp) {
    if (hmminfo->sp == NULL) {
      jlog("Error: mkwhmm: no short-pause model in hmminfo\n");
      return NULL;
    }
  }

  /* allocate needed states */
  new = (HMM *)mymalloc(sizeof(HMM));
  new->len = totalstatelen(hdseq, hdseqlen, has_sp, hmminfo);
  new->state = (HMM_STATE *)mymalloc(sizeof(HMM_STATE) * new->len);
  for (i=0;i<new->len;i++) {
    new->state[i].ac = NULL;
    new->state[i].is_pseudo_state = FALSE;
    new->state[i].out.state = NULL;
    new->state[i].out.cdset = NULL;
  }

  /* assign outprob informations into the states  */
  n = 0;
  if (hmminfo->multipath) n++;  /* skip first state */
  for (i = 0; i < hdseqlen; i++) {
    if (hdseq[i]->is_pseudo) {
      for (j = 1; j < hdseq[i]->body.pseudo->state_num - 1; j++) {
        new->state[n].is_pseudo_state = TRUE;
        new->state[n].out.cdset = &(hdseq[i]->body.pseudo->stateset[j]);
        n++;
      }
    } else {
      for (j = 1; j < hdseq[i]->body.defined->state_num - 1; j++) {
        new->state[n].is_pseudo_state = FALSE;
        new->state[n].out.state = hdseq[i]->body.defined->s[j];
        n++;
      }
    }
    if (has_sp) {
      if (has_sp[i]) {
        /* append sp at the end of the phone */
        if (hmminfo->sp->is_pseudo) {
          for (j = 1; j < hmm_logical_state_num(hmminfo->sp) - 1; j++) {
            new->state[n].is_pseudo_state = TRUE;
            new->state[n].out.cdset = &(hmminfo->sp->body.pseudo->stateset[j]);
            n++;
          }
        } else {
          for (j = 1; j < hmm_logical_state_num(hmminfo->sp) - 1; j++) {
            new->state[n].is_pseudo_state = FALSE;
            new->state[n].out.state = hmminfo->sp->body.defined->s[j];
            n++;
          }
        }
      }
    }
  }
  
  /* make transition arcs between each state*/
/* 
 *   for (i=0;i<hdseq[0]->def->state_num;i++) {
 *     if (i != 1 && (hdseq[0]->def->tr->a[0][i]) != LOG_ZERO) {
 *       jlog("initial state contains more than 1 arc.\n");
 *     }
 *   }
 */

  if (hmminfo->multipath) {

    int *out_from, *out_from_next;
    LOGPROB *out_a, *out_a_next;
    int out_num_prev, out_num_next;
    out_from = (int *)mymalloc(sizeof(int) * new->len);
    out_from_next = (int *)mymalloc(sizeof(int) * new->len);
    out_a = (LOGPROB *)mymalloc(sizeof(LOGPROB) * new->len);
    out_a_next = (LOGPROB *)mymalloc(sizeof(LOGPROB) * new->len);

    n = 0;                      /* n points to previous state */

    out_from[0] = 0;
    out_a[0] = 0.0;
    out_num_prev = 1;
    for (i = 0; i < hdseqlen; i++) {
      state_num = hmm_logical_state_num(hdseq[i]);
      tr = hmm_logical_trans(hdseq[i]);
      out_num_next = 0;
      /* arc from initial state */
      for (ato = 1; ato < state_num; ato++) {
        logprob = tr->a[0][ato];
        if (logprob != LOG_ZERO) {
          /* expand arc */
          if (ato == state_num-1) {
            /* from initial to final ... register all previously registered arcs for next expansion */
            if (lscore != NULL) logprob += lscore[i];
            for(j=0;j<out_num_prev;j++) {
              out_from_next[out_num_next] = out_from[j];
              out_a_next[out_num_next] = out_a[j] + logprob;
              out_num_next++;
            }
          } else {
            for(j=0;j<out_num_prev;j++) {
              add_arc(&(new->state[out_from[j]]), n + ato,
                      out_a[j] + logprob);
            }
          }
        }
      }
      /* arc from output state */
      for(afrom = 1; afrom < state_num - 1; afrom++) {
        for (ato = 1; ato < state_num; ato++) {
          logprob = tr->a[afrom][ato];
          if (logprob != LOG_ZERO) {
            if (ato == state_num - 1) {
              /* from output state to final ... register the arc for next expansion */
              if (lscore != NULL) logprob += lscore[i];
              out_from_next[out_num_next] = n+afrom;
              out_a_next[out_num_next++] = logprob;
            } else {
              add_arc(&(new->state[n+afrom]), n + ato, logprob);
            }
          }
        }
      }
      n += state_num - 2;
      for(j=0;j<out_num_next;j++) {
        out_from[j] = out_from_next[j];
        out_a[j] = out_a_next[j];
      }
      out_num_prev = out_num_next;

      /* inter-word short pause handling */
      if (has_sp && has_sp[i]) {
      
        out_num_next = 0;

        /* arc from initial state */
        for (ato = 1; ato < hmm_logical_state_num(hmminfo->sp); ato++) {
          logprob = hmm_logical_trans(hmminfo->sp)->a[0][ato];
          if (logprob != LOG_ZERO) {
            /* to control short pause insertion, transition probability toward
               the word-end short pause will be given a penalty */
            logprob += hmminfo->iwsp_penalty;
            /* expand arc */
            if (ato == hmm_logical_state_num(hmminfo->sp)-1) {
              /* from initial to final ... register all previously registered arcs for next expansion */
              for(j=0;j<out_num_prev;j++) {
                out_from_next[out_num_next] = out_from[j];
                out_a_next[out_num_next] = out_a[j] + logprob;
                out_num_next++;
              }
            } else {
              for(j=0;j<out_num_prev;j++) {
                add_arc(&(new->state[out_from[j]]), n + ato,
                        out_a[j] + logprob);
              }
            }
          }
        }
        /* if short pause model doesn't have a model skip transition, also add it */
        if (hmm_logical_trans(hmminfo->sp)->a[0][hmm_logical_state_num(hmminfo->sp)-1] == LOG_ZERO) {
          /* to make insertion sp model to have no effect on the original path,
             the skip transition probability should be 0.0 (=100%) */
          logprob = 0.0;
          for(j=0; j<out_num_prev; j++) {
            out_from_next[out_num_next] = out_from[j];
            out_a_next[out_num_next] = out_a[j] + logprob;
            out_num_next++;
          }
        }
        /* arc from output state */
        for(afrom = 1; afrom < hmm_logical_state_num(hmminfo->sp) - 1; afrom++) {
          for (ato = 1; ato < hmm_logical_state_num(hmminfo->sp); ato++) {
            logprob = hmm_logical_trans(hmminfo->sp)->a[afrom][ato];
            if (logprob != LOG_ZERO) {
              if (ato == hmm_logical_state_num(hmminfo->sp) - 1) {
                /* from output state to final ... register the arc for next expansion */
                out_from_next[out_num_next] = n+afrom;
                out_a_next[out_num_next++] = logprob;
              } else {
                add_arc(&(new->state[n+afrom]), n + ato, logprob);
              }
            }
          }
        }
        n += hmm_logical_state_num(hmminfo->sp) - 2;
        for(j=0;j<out_num_next;j++) {
          out_from[j] = out_from_next[j];
          out_a[j] = out_a_next[j];
        }
        out_num_prev = out_num_next;
      }
    }
      
    
    for(j=0;j<out_num_prev;j++) {
      add_arc(&(new->state[out_from[j]]), new->len-1, out_a[j]);
    }
    free(out_from);
    free(out_from_next);
    free(out_a);
    free(out_a_next);

  } else {
    /* non-multipath version */

    new->accept_ac_a = LOG_ZERO;
    n = 0;
    for (i = 0; i < hdseqlen; i++) {
      state_num = hmm_logical_state_num(hdseq[i]);
      tr = hmm_logical_trans(hdseq[i]);
      /* for each phoneme, consult the transition matrix to form HMM instance */
      for (afrom = 1; afrom < state_num - 1; afrom++) {
        for (ato = 1; ato < state_num; ato++) {
          logprob = tr->a[afrom][ato];
          if (logprob != LOG_ZERO) {
            /* if emitting transition, add connection probability to the arc */
            if (ato == state_num - 1 && lscore != NULL){
              logprob += lscore[i];
            }
            if (n + (ato - afrom) >= new->len) { /* arc to accept node */
              if (new->accept_ac_a != LOG_ZERO) {
                jlog("Error: mkwhmm: more than 1 arc to accept node found\n");
                return NULL;
                
              } else {
                new->accept_ac_a = logprob;
              }
            } else {
              add_arc(&(new->state[n]), n + (ato - afrom), logprob);
            }
          }
        }
        n++;
      }
    }
  }

  return (new);
}

HMM *
new_make_word_hmm(HTK_HMM_INFO *hmminfo, HMM_Logical **hdseq, int hdseqlen, boolean *has_sp)
{
  return(new_make_word_hmm_with_lm(hmminfo, hdseq, hdseqlen, has_sp, NULL));
}

void
free_hmm(HMM *d)
{
  A_CELL *ac, *atmp;
  int i;

  for (i=0;i<d->len;i++) {
    ac = d->state[i].ac;
    while (ac) {
      atmp = ac->next;
      free(ac);
      ac = atmp;
    }
  }
  free(d->state);
  free(d);
}