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Subject: Re: Pawn hashing without Zobrist keys

Author: Gian-Carlo Pascutto

Date: 14:00:25 09/12/03

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On September 12, 2003 at 16:53:44, Omid David Tabibi wrote:

>assuming 'table_size' is a power of 2, the following two expressions are
>equivalent:
>
>address = key % table_size;
>address = key & (table_size - 1);

That's exactly the problem. He generates his hashkeys by
taking the differnce of the white and black pawn bitboard.

If you 'AND' off a piece of that, you're just cutting out a part
of your board - with massive hash collisions as a result.

You want something more nonlinear.

--
GCP

• Re: Pawn hashing without Zobrist keys Vincent Diepeveen 17:58:33 09/12/03
  • Re: Pawn hashing without Zobrist keys Gerd Isenberg 00:06:21 09/13/03
    • Re: Pawn hashing without Zobrist keys Uri Blass 02:25:36 09/13/03
      • Re: Pawn hashing without Zobrist keys Gerd Isenberg 03:01:12 09/13/03
        • Re: Pawn hashing without Zobrist keys Uri Blass 04:40:45 09/13/03
          • Re: Pawn hashing without Zobrist keys Gerd Isenberg 05:55:54 09/13/03
• Re: Pawn hashing without Zobrist keys Omid David Tabibi 14:09:42 09/12/03
  • Re: Pawn hashing without Zobrist keys Gian-Carlo Pascutto 14:13:14 09/12/03

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