PocketSphinx  5prealpha
ngram_search.c File Reference

N-Gram based multi-pass search ("FBS") More...

#include <string.h>
#include <assert.h>
#include <sphinxbase/ckd_alloc.h>
#include <sphinxbase/listelem_alloc.h>
#include <sphinxbase/err.h>
#include "pocketsphinx_internal.h"
#include "ps_lattice_internal.h"
#include "ngram_search.h"
#include "ngram_search_fwdtree.h"
#include "ngram_search_fwdflat.h"

Go to the source code of this file.

Macros

#define NGRAM_HISTORY_LONG_WORD   2000 /* 20s */
 

Functions

ps_search_tngram_search_init (const char *name, ngram_model_t *lm, cmd_ln_t *config, acmod_t *acmod, dict_t *dict, dict2pid_t *d2p)
 Initialize the N-Gram search module.
 
void ngram_search_free (ps_search_t *search)
 Finalize the N-Gram search module.
 
int ngram_search_mark_bptable (ngram_search_t *ngs, int frame_idx)
 Record the current frame's index in the backpointer table. More...
 
void ngram_search_save_bp (ngram_search_t *ngs, int frame_idx, int32 w, int32 score, int32 path, int32 rc)
 Enter a word in the backpointer table.
 
int ngram_search_find_exit (ngram_search_t *ngs, int frame_idx, int32 *out_best_score)
 Find the best word exit for the current frame in the backpointer table. More...
 
char const * ngram_search_bp_hyp (ngram_search_t *ngs, int bpidx)
 Backtrace from a given backpointer index to obtain a word hypothesis. More...
 
void ngram_search_alloc_all_rc (ngram_search_t *ngs, int32 w)
 Allocate last phone channels for all possible right contexts for word w.
 
void ngram_search_free_all_rc (ngram_search_t *ngs, int32 w)
 Allocate last phone channels for all possible right contexts for word w.
 
int32 ngram_search_exit_score (ngram_search_t *ngs, bptbl_t *pbe, int rcphone)
 Get the exit score for a backpointer entry with a given right context.
 
void ngram_compute_seg_score (ngram_search_t *ngs, bptbl_t *be, float32 lwf, int32 *out_ascr, int32 *out_lscr)
 
void dump_bptable (ngram_search_t *ngs)
 
ps_lattice_tngram_search_lattice (ps_search_t *search)
 Construct a word lattice from the current hypothesis.
 
void ngram_search_set_lm (ngram_model_t *lm)
 Sets the global language model. More...
 

Detailed Description

N-Gram based multi-pass search ("FBS")

Definition in file ngram_search.c.

Function Documentation

char const* ngram_search_bp_hyp ( ngram_search_t ngs,
int  bpidx 
)

Backtrace from a given backpointer index to obtain a word hypothesis.

Returns
a read-only string with the best hypothesis.

Definition at line 550 of file ngram_search.c.

References bptbl_s::bp, dict_real_word(), ps_search_s::hyp_str, and bptbl_s::wid.

int ngram_search_find_exit ( ngram_search_t ngs,
int  frame_idx,
int32 *  out_best_score 
)

Find the best word exit for the current frame in the backpointer table.

Returns
the backpointer index of the best word exit.

Definition at line 506 of file ngram_search.c.

References BETTER_THAN, ngram_search_s::n_frame, bptbl_s::score, bptbl_s::wid, and WORST_SCORE.

int ngram_search_mark_bptable ( ngram_search_t ngs,
int  frame_idx 
)

Record the current frame's index in the backpointer table.

Returns
the current backpointer index.

Definition at line 329 of file ngram_search.c.

References ngram_search_s::frm_wordlist, and ngram_search_s::n_frame_alloc.

Referenced by ngram_fwdflat_finish(), ngram_fwdflat_search(), ngram_fwdtree_finish(), and ngram_fwdtree_search().

void ngram_search_set_lm ( ngram_model_t *  lm)

Sets the global language model.

Sets the language model to use if nothing was passed in configuration

Definition at line 1403 of file ngram_search.c.