https://github.com/titsuki/raku-algorithm-zobristhashing

a hash function for board games
https://github.com/titsuki/raku-algorithm-zobristhashing

Last synced: 3 months ago
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a hash function for board games

• Host: GitHub
• URL: https://github.com/titsuki/raku-algorithm-zobristhashing
• Owner: titsuki
• License: artistic-2.0
• Created: 2016-02-22T04:28:36.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2024-08-09T00:41:15.000Z (5 months ago)
• Last Synced: 2024-08-10T01:26:01.132Z (5 months ago)
• Language: Raku
• Size: 17.6 KB
• Stars: 1
• Watchers: 2
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • Changelog: Changes
  • License: LICENSE

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README

        
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NAME

====

Algorithm::ZobristHashing - a hash function for board games

SYNOPSIS

========

    use Algorithm::ZobristHashing;

    # the case input is Str

    my $zobrist = Algorithm::ZobristHashing.new();

    my $status = $zobrist.encode("Perl6 is fun");

    my $code = $zobrist.get(0,"P"); # Int value which represents state h(0,"P")

    my $code = $zobrist.get(5," "); # Int value which represents state h(5," ")

    # the case input is Array

    my $zobrist = Algorithm::ZobristHashing.new();

    my $status = $zobrist.encode([["Perl6"],["is"],["fun"]]);

    my $code = $zobrist.get(0,"Perl6"); # Int value which represents state h(0,"Perl6")

DESCRIPTION

===========

Algorithm::ZobristHashing is a hash function for board games such as chess, GO, GO-MOKU, tic-tac-toe, and so on. 

CONSTRUCTOR

-----------

### new

    my $zobrist = Algorithm::ZobristHashing.new(%options);

#### OPTIONS

  * `max-rand => $max-rand`

Sets the upper bound number for generating random number. Default is 1e9.

METHODS

-------

### encode(Str|Array)

    my $status = $zobrist.encode("abc"); # h(0,"a") xor h(1,"b") xor h(2,"c")

    my $status = $zobrist.encode([["a"],["b"],["c"]]); # h(0,"a") xor h(1,"b") xor h(2,"c")

    my $status = $zobrist.encode([["ab"],["c"]]); # h(0,"ab") xor h(1,"c")

Returns the hash value which represents the status of the input sequence. If the input value is the nested array, it flattens this and handles as a 1-dimensional array. If the input value is empty, it returns the type object Int.

### get(Int $position, Str $type)

    my $status = $zobrist.encode(["abc"]);

    my $code = $zobrist.get(0,"abc"); # in this case $code == $status

    my $new-code = $zobrist.get(0,"perl"); # assigns a new rand value, since h(0,"perl") is not yet encoded

Returns the Int value which represents the state(i.e position-type pair). If it intends to get the state not yet encoded, it assigns a new rand value to the state and returns this new value.

AUTHOR

======

titsuki 

COPYRIGHT AND LICENSE

=====================

Copyright 2016 titsuki

This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.

This algorithm is from Zobrist, Albert L. "A new hashing method with application for game playing." ICCA journal 13.2 (1970): 69-73.