cmph1

Minimum perfect hashing tool

Usage

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

Overview

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

Examples

$ # 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

Releases

9 releases since Debian 5.0 (Lenny); the text changed 1 time.