MKBINGRAM(1)

NAME
mkbingram - make binary N-gram from arpa N-gram file

SYNOPSIS
mkbingram -nlr forward_ngram.arpa -nrl backward_ngram.arpa bingram

DESCRIPTION
mkbingram makes a binary N-gram file for Julius from forward (left-to-right) word N-gram and/or backward (right-to-left) word N-gram LMs in ARPA standard format. Using the binary file, the initial startup of Julius becomes much faster.

From rev. 4.0, longer N-gram (N < 10) is supported.

When only a forward N-gram is specified by "-nlr" and no backward N-gram is specified, mkbingram generates binary N-gram for recognition with only the forward N-gram. The 1st pass will use the 2-gram entry in the given N-gram, and The 2nd pass will use the given N-gram, with converting forward probabilities to backward probabilities by Bayes rule.

When only a backward N-gram is specified by "-nrl" and no forward N-gram is specified, mkbingram generates binary N-gram for recognition with only the backward N-gram. The 1st pass will use the forward 2-gram probability computed from the backward 2-gram using Bayes rule. The 2nd pass fully use the given backward N-gram.

When both forward and backward N-grams are specified, forward 2-gram part and backward N-gram are gathered together into single bingram file, to use the forward 2-gram for the 1st pass and backward N-gram for the 2nd pass. Note that both N-gram should be trained in the same corpus with same parameters (i.e. cut-off thresholds), with same vocabulary.

mkbingram can read gzipped ARPA file.

Please note that binary N-gram file converted by mkbingram of version 4.0 and later cannot be read by Julius 3.x.

OPTIONS
Forward (left-to-right) word N-gram file in ARPA standard format. Backward (right-to-left) word N-gram file in ARPA standard format. Read in an old binary N-gram file (for conversion to the new format). output binary N-gram file.

EXAMPLE
Convert ARPA files to binary format:

    % mkbingram -nlr ARPA_2gram -nrl ARPA_rev_3gram outfile

Convert old binary N-gram file to new format:

    % mkbingram -d old_bingram new_bingram

SEE ALSO
julius(1)

COPYRIGHT
Copyright (c) 1991-2007 Kawahara Lab., Kyoto University
Copyright (c) 2000-2005 Shikano Lab., Nara Institute of Science and Technology
Copyright (c) 2005-2007 Julius project team, Nagoya Institute of Technology

AUTHORS
LEE Akinobu (Nagoya Institute of Technology, Japan)
contact: julius-info at lists.sourceforge.jp

LICENSE
Same as Julius.