NAME
ids2ngram - generate n-gram data file from ids file
SYNOPSIS
ids2ngram [option]... ids_file...
DESCRIPTION
ids2ngram generates idngram file, which is a sorted [id1,..,idN,freq]
array, from binary id stream files. Here, the id stream files are
always generated by mmseg or slmseg. Basically, it finds all occurrence
of n-words tuples (i.e. the tuple of (id1,..,idN)), and sorts these
tuples by the lexicographic order of the ids make up the tuples, then
write them to specified output file.
INPUT
The input file is presented as a binary id stream, which looks like:
[id0,...,idX]
OPTIONS
All the following options are mandatory.
-n,--NMax N
Generates N-gram result. ids2ngram does only support uni-gram, bi-
gram, and trigram, so any number not in the range of 1..3 is not
valid.
-s,--swap swap-file
Specify the temporary intermediate file.
-o, --out output-file
Specify the result idngram file, e.g. the array of [id1, ..., idN,
freq]
-p, --para N
Specify the maximum n-gram items per paragraph. ids2ngram writes to
the temporary file on a per-paragraph basis. Every time it writes a
paragraph out, it frees the corresponding memory allocated for it.
When your computer system permits, a higher N is suggested. This
can speed up the processing speed because of less I/O.
EXAMPLE
Following example will use three input idstream file idsfile[1,2,3] to
generate the idngram file all.id3gram. Each para (internal map size or
hash size) would be 1024000, using swap file for temp result. All temp
para result would eventually be merged to got the final result.
ids2ngram -n 3 -s /tmp/swap -o all.id3gram -p 1024000 idsfile1 idsfile2
idsfile3
AUTHOR
Originally written by Phill.Zhang <phill.zhang@sun.com>. Currently
maintained by Kov.Chai <tchaikov@gmail.com>.
SEE ALSO
mmseg(1), slmseg(1), slmbuild (1).