Re: Fwd: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-14 Thread Unknown
On Wed, 2007-02-14 at 10:45 +0100, Erik van der Werf wrote: From: Nic Schraudolph [EMAIL PROTECTED] Date: 12 February 2007 10:45:50 GMT+11:00 To: computer-go computer-go@computer-go.org Subject: Re: [computer-go] Zobrist hashing with easy transformation comparison did you read Anti

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-13 Thread Jacques Basaldúa
Hi Erik And what distinguishes database look up from things like transposition table look up? Why wouldn't one use database look up during tree search? The interest in rotation/mirror. In database search, what is good for a position is good for the mirror/rotation. In tree search, rotation of

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-12 Thread Jacques Basaldúa
Erik van der Werf wrote: And then we get another small questions with a dangerous answer... 1. What makes a question big or small is not a personal preference, but the number of millions times it happens during a game. 1a. Database lookup. Happens very few times (Unfortunately, I must

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-12 Thread Erik van der Werf
On 2/12/07, Jacques Basaldúa [EMAIL PROTECTED] wrote: Erik van der Werf wrote: And then we get another small questions with a dangerous answer... 1. What makes a question big or small is not a personal preference, but the number of millions times it happens during a game. Can't take a

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-11 Thread Antoine de Maricourt
Please do. I will put it on a web page. But I need some time. My job keeps me very busy right now. But I'm not sure I will post the statistical analysis (it was almost ten hand writen pages, and I'm not sure I still have them). Have You performed an empirical test for collisions? No,

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-11 Thread Antoine de Maricourt
On 2/10/07, Łukasz Lew [EMAIL PROTECTED] wrote: On 2/10/07, Antoine de Maricourt [EMAIL PROTECTED] wrote: If there is strong interest, I can post the scheme. Please do. Since Antoine claims there is only on solution I might as well post mine ;-) mirroring: [abcdefgh] - [hgfedcba]

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-10 Thread Erik van der Werf
On 2/10/07, Łukasz Lew [EMAIL PROTECTED] wrote: On 2/10/07, Antoine de Maricourt [EMAIL PROTECTED] wrote: If there is strong interest, I can post the scheme. Please do. Since Antoine claims there is only on solution I might as well post mine ;-) mirroring: [abcdefgh] - [hgfedcba] rotation:

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-10 Thread Jacques Basaldúa
As Antoine de Maricourt says, this weakens the key. I think it is a serious problem and it is a dangerous answer to a small question. I compute hashes and patterns for database lookup eight at a time, which is faster (much more optimizable) than one after the other. Then I also use the smallest

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-10 Thread Erik van der Werf
On 2/10/07, Jacques Basaldúa [EMAIL PROTECTED] wrote: snip But the question is: Does someone do the opposite, i.e. playing with the hash values to make then *stronger*? And then we get another small questions with a dangerous answer... Just search the archive for BCH construction. E.

[computer-go] Zobrist hashing with easy transformation comparison

2007-02-09 Thread Nick Apperson
Hey all, I was thinking about our conversation and i decided to design a zobrist class that allows for easy comparison to check and see if 2 different zobrist values are equivalent after a rotation etc... It updates the zobrist in such a way that it can transform them and after trying 8

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-09 Thread Antoine de Maricourt
Hi, did you read Anti Huima's paper? The idea looks similar, but unfortunately it does not work. I provided a proof of the defect on this list (end of 2002 if I remember well). It's not that easy to get a working scheme. In fact there is only one combination with 8 chunks of data. In 2002 I

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-09 Thread Łukasz Lew
On 2/10/07, Antoine de Maricourt [EMAIL PROTECTED] wrote: Hi, did you read Anti Huima's paper? The idea looks similar, but unfortunately it does not work. I provided a proof of the defect on this list (end of 2002 if I remember well). It's not that easy to get a working scheme. In fact there is

Re: [computer-go] Zobrist hashing with easy transformation comparison

2007-02-09 Thread Nick Apperson
Sorry for posting then, I didn't realize that it had been tried. I may work through the problem and try to get it to work in order to fully understand why it in fact does not work. If by some miracle I manage to get something working with a collision rate of 1/(2^61) I'll certainly post it.