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Subject: Re: "Parallel chess searching and bitboards"

Author: Gerd Isenberg

Date: 00:39:00 09/18/04

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On September 17, 2004 at 14:33:41, Dann Corbit wrote:

>http://www.imm.dtu.dk/pubdb/views/publication_details.php?id=3267
>
>I got ~96% efficiency, going from 1 thread to 2 threads on a dual CPU machine.
>1172442 / 599317 = 1.9563
>

A cool paper, good explanation, very well structured and readable source code.
A realy great C++ repository.

About the Issue "Parallel Chess Searching with Bitboards", i have the same
problem as others to get David's point, what makes the board representation or
it's additional size of 17 bitboards so unique while splitting nodes?

The rotated bitboard approach is the "classical" as described by Bob Hyatt and
Ernst Heinz, with 256 occupied states:
http://www.cis.uab.edu/hyatt/bitmaps.html
http://supertech.lcs.mit.edu/~heinz/dt/node8.html

What is the difference between David's lockless hashing approach and Bob
Hyatt's? Isn't it the same xor idea?
http://www.cis.uab.edu/hyatt/hashing.html

Btw. is a 128-bit movdqa-instruction sufficent as an atomic read or write
operation?

Thanks,
Gerd



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