NAME¶

cmph - minimum perfect hashing tool

SYNOPSIS¶

cmph [-v] [-h] [-V] [-k nkeys] [-f hash_function] [-g [-c value][-s seed] ] [-a algorithm] [-M memory_in_MB] [-b BRZ_parameter] [-d tmp_dir] [-m file.mph] keysfile

DESCRIPTION¶

Command line tool to generate and query minimal perfect hash functions.

Please refer to http://cmph.sf.net for full documentation.

-h

Print an help message

-c

This value determines: the number of vertices in the graph for the algorithms BMZ and CHM; the number of bits per key required in the FCH algorithm

-a

Algorithm. Valid values are: bmz, bmz8, chm, brz, fch

-f

hash function (may be used multiple times). valid values are: djb2, fnv, jenkins, sdbm

-V

Print version number and exit

-v

Increase verbosity (may be used multiple times)

-k

Number of keys

-g

Generation mode

-s

Random seed

-m

Minimum perfect hash function file

-M

Main memory availability (in MB)

-d

Temporary directory used in brz algorithm

-b

Parameter of BRZ algorithm to make the maximal number of keys in a bucket lower than 256

keysfile

Line separated file with keys

EXAMPLE¶

$ # Using the default algorithm (chm) for constructing a mphf
$ # for keys in file keys_file. Lines in keys_file _must_ be unique.
$ ./cmph -v -g keys_file
$ # Query id of keys in the file keys_query
$ ./cmph -v -m keys_file.mph keys_query

AUTHOR¶

This manual page was written by Enrico Tassi <gareuselesinge@users.sourceforge.net>, for the Debian project (but may be used by others).