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"

Macros
#define	NGRAM_HISTORY_LONG_WORD 2000 /* 20s */

Functions
ps_search_t *	ngram_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.

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.

char const *	ngram_search_bp_hyp (ngram_search_t *ngs, int bpidx)
	Backtrace from a given backpointer index to obtain a word hypothesis.

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_t *	ngram_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.

Detailed Description

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

Definition in file ngram_search.c.

Macro Definition Documentation

◆ NGRAM_HISTORY_LONG_WORD

#define NGRAM_HISTORY_LONG_WORD 2000 /* 20s */

Definition at line 380 of file ngram_search.c.

Function Documentation

◆ dump_bptable()

void dump_bptable ( ngram_search_t * ngs )

Definition at line 756 of file ngram_search.c.

◆ ngram_compute_seg_score()

void ngram_compute_seg_score	(	ngram_search_t *	ngs,
		bptbl_t *	be,
		float32	lwf,
		int32 *	out_ascr,
		int32 *	out_lscr
	)

Definition at line 685 of file ngram_search.c.

◆ ngram_search_alloc_all_rc()

void ngram_search_alloc_all_rc	(	ngram_search_t *	ngs,
		int32	w
	)

Allocate last phone channels for all possible right contexts for word w.

Definition at line 598 of file ngram_search.c.

References ngram_search_s::chan_alloc, chan_s::ciphone, dict2pid_rssid, chan_s::hmm, ngram_search_s::hmmctx, xwdssid_t::n_ssid, chan_s::next, chan_s::rc_id, xwdssid_t::ssid, and ngram_search_s::word_chan.

◆ ngram_search_bp_hyp()

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, ps_search_s::hyp_str, and bptbl_s::wid.

◆ ngram_search_exit_score()

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.

Definition at line 660 of file ngram_search.c.

References xwdssid_t::cimap, dict2pid_rssid, bptbl_s::last2_phone, bptbl_s::last_phone, bptbl_s::s_idx, and bptbl_s::score.

Referenced by ngram_search_lattice().

◆ ngram_search_find_exit()

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.

◆ ngram_search_free()

void ngram_search_free ( ps_search_t * search )

Finalize the N-Gram search module.

Definition at line 289 of file ngram_search.c.

References ngram_search_s::active_word_list, ngram_search_s::chan_alloc, ngram_search_s::hmmctx, ngram_search_s::latnode_alloc, ngram_search_s::lmset, ngram_fwdflat_deinit(), ngram_fwdtree_deinit(), ngram_search_s::root_chan_alloc, ngram_search_s::word_active, and ngram_search_s::word_chan.

Referenced by ngram_search_init().

◆ ngram_search_free_all_rc()

void ngram_search_free_all_rc	(	ngram_search_t *	ngs,
		int32	w
	)

Allocate last phone channels for all possible right contexts for word w.

Definition at line 647 of file ngram_search.c.

References ngram_search_s::chan_alloc, chan_s::hmm, chan_s::next, and ngram_search_s::word_chan.

Referenced by ngram_fwdtree_finish().

◆ ngram_search_init()

ps_search_t * ngram_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.

Definition at line 140 of file ngram_search.c.

References acmod_set_grow(), ngram_search_s::active_word_list, ngram_search_s::chan_alloc, dict_size, ngram_search_s::hmmctx, ngram_search_s::latnode_alloc, ngram_search_s::lmset, acmod_s::mdef, ngram_search_s::n_frame_alloc, ngram_fwdflat_init(), ngram_fwdtree_init(), ngram_search_free(), ngram_search_s::root_chan_alloc, bin_mdef_s::sseq, acmod_s::tmat, tmat_t::tp, ngram_search_s::word_active, and ngram_search_s::word_chan.

Referenced by ps_set_lm().

◆ ngram_search_lattice()

ps_lattice_t * ngram_search_lattice ( ps_search_t * search )

Construct a word lattice from the current hypothesis.

Definition at line 1215 of file ngram_search.c.

References ps_latnode_s::alt, ps_latnode_s::basewid, ngram_search_s::best_score, BETTER_THAN, ps_search_s::dag, ps_search_s::dict, ps_lattice_s::end, ps_latnode_s::fef, ps_lattice_s::final_node_ascr, bptbl_s::frame, ps_lattice_s::latnode_alloc, ps_latnode_s::lef, ngram_search_s::n_frame, ps_lattice_s::n_frames, ps_lattice_s::n_nodes, ps_latnode_s::next, ngram_search_exit_score(), ps_lattice_s::nodes, ps_lattice_delete_unreachable(), ps_lattice_free(), ps_lattice_init_search(), ps_lattice_link(), ps_lattice_penalize_fillers(), ps_latnode_s::reachable, bptbl_s::score, ps_latnode_s::sf, ps_lattice_s::start, bptbl_s::wid, ps_latnode_s::wid, WORSE_THAN, and WORST_SCORE.

◆ ngram_search_mark_bptable()

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().

◆ ngram_search_save_bp()

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.

Definition at line 383 of file ngram_search.c.

References bptbl_s::bp, dict2pid_rssid, bptbl_s::frame, bptbl_s::last2_phone, bptbl_s::last_phone, bptbl_s::prev_real_wid, bptbl_s::real_wid, bptbl_s::s_idx, bptbl_s::score, bptbl_s::valid, bptbl_s::wid, WORSE_THAN, and WORST_SCORE.

◆ ngram_search_set_lm()

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.

Macros

Functions