libsent/src/hmminfo/check_hmm_restriction.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
 */

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

boolean
htk_hmm_has_several_arc_on_edge(HTK_HMM_INFO *hmminfo)
{
  HTK_HMM_Data *dt;
  HTK_HMM_Trans *t;
  boolean flag;
  int i;

  for (dt = hmminfo->start; dt; dt = dt->next) {
    t = dt->tr;
    flag = FALSE;
    for (i=0;i<t->statenum;i++) {
      if (t->a[0][i] != LOG_ZERO) {
        if (flag == FALSE) {
          flag = TRUE;
        } else {
          jlog("Stat: check_hmm_restriction: an HMM with several arcs from initial state found: \"%s\"\n", dt->name);
          return (TRUE);
        }
      }
    }
    flag = FALSE;
    for (i=0;i<t->statenum;i++) {
      if (t->a[i][t->statenum-1] != LOG_ZERO) {
        if (flag == FALSE) {
          flag = TRUE;
        } else {
          jlog("Stat: check_hmm_restriction: an HMM with several arcs to final state found: \"%s\"\n", dt->name);
          return (TRUE);
        }
      }
    }
  }

  return FALSE;
}

static boolean
trans_ok_p(HTK_HMM_Trans *t)
{
  int i;
  int tflag;
  int retflag = TRUE;

  /* check arc to initial state */
  tflag = FALSE;
  for (i=0;i<t->statenum;i++) {
    if (t->a[i][0] != LOG_ZERO) {
      tflag = TRUE;
      break;
    }
  }
  if (tflag) {
    jlog("Error: check_hmm_restriction: transition to initial state is not allowed\n");
    retflag = FALSE;
  }
  /* check arc from final state */
  tflag = FALSE;
  for (i=0;i<t->statenum;i++) {
    if (t->a[t->statenum-1][i] != LOG_ZERO) {
      tflag = TRUE;
      break;
    }
  }
  if (tflag) {
    jlog("Error: check_hmm_restriction: transition from final state is not allowed\n");
    retflag = FALSE;
  }
  /* check if arc from/to initial/final state exist */
  tflag = FALSE;
  for (i=0;i<t->statenum;i++) {
    if (t->a[0][i] != LOG_ZERO) {
      tflag = TRUE;
      break;
    }
  }
  if (tflag == FALSE) {
    jlog("Error: check_hmm_restriction: no transition from initial state\n");
    retflag = FALSE;
  }
  tflag = FALSE;
  for (i=0;i<t->statenum;i++) {
    if (t->a[i][t->statenum-1] != LOG_ZERO) {
      tflag = TRUE;
      break;
    }
  }
  if (tflag == FALSE) {
    jlog("Error: check_hmm_restriction: no transition to final state\n");
    retflag = FALSE;
  }
    
  return(retflag);
}

boolean
check_hmm_limit(HTK_HMM_Data *dt)
{
  boolean return_flag = TRUE;

  if (trans_ok_p(dt->tr) == FALSE) {
    return_flag = FALSE;
    jlog("Error: check_hmm_restriction: HMM \"%s\" has unsupported arc.\n", dt->name);
    put_htk_trans(jlog_get_fp(), dt->tr);
  }
  if (dt->tr->statenum < 3) {
    return_flag = FALSE;
    jlog("Error: HMM \"%s\" has no output state (statenum=%d)\n", dt->name, dt->tr->statenum);
  }
  return(return_flag);
}

boolean
check_all_hmm_limit(HTK_HMM_INFO *hmminfo)
{
  HTK_HMM_Data *dt;
  boolean return_flag = TRUE;

  for (dt = hmminfo->start; dt; dt = dt->next) {
    if (check_hmm_limit(dt) == FALSE) {
      return_flag = FALSE;
    }
  }
  return(return_flag);
}


boolean
is_skippable_model(HTK_HMM_Data *d)
{
  if (d->tr->a[0][d->tr->statenum-1] != LOG_ZERO) {
    return TRUE;
  }
  return FALSE;
}