libjulius/src/search_bestfirst_v2.c File Reference

Viterbi path update and scoring on the second pass (standard version). More...

#include <julius/julius.h>

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Detailed Description

Viterbi path update and scoring on the second pass (standard version).

This file has functions for score calculations on the 2nd pass. It includes Viterbi path update calculation of a hypothesis, calculations of scores and word trellis connection at word expansion.

The cross-word triphone will be computed just at word expansion time, for precise scoring. This is called "nextscan" altgorithm. These functions are enabled when PASS2_STRICT_IWCD is DEFINED in config.h. If undefined, the "backscan" functions in search_bestfirst_v1.c will be used instead.

Here in nextscan algorithm, all cross-word context dependencies between next word and source hypothesis are computed as soon as a new hypotheses is expanded. As the precise cross-word triphone score is applied on hypothesis generation with no delay, more accurate search-time score can be obtained than the delayed backscan method in search_bestfirst_v1.c. On the other hand, the computational cost grows much by re-calculating forward score of cross-word triphones for all the generated hypothethes, even non-promising ones.

Author:
Akinobu Lee
Date:
Mon Sep 12 00:58:50 2005
Revision
1.1.1.1

Definition in file search_bestfirst_v2.c.


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