Re: [computer-go] Kinds of Zobrist hashes

2009-12-09 Thread Petr Baudis
Hi! Thanks to all for replies. On Tue, Dec 08, 2009 at 09:30:47PM -0500, Eric Boesch wrote: You can mathematically prove the two systems are almost the same, so there's no need to test. Yes, this was my line of thought, but I wasn't sure if I'm not missing anything...

Re: [computer-go] Kinds of Zobrist hashes

2009-12-09 Thread Christian Nentwich
On Tue, Dec 08, 2009 at 09:30:47PM -0500, Eric Boesch wrote: You can mathematically prove the two systems are almost the same, so there's no need to test. Yes, this was my line of thought, but I wasn't sure if I'm not missing anything... If you ever decide to test which is faster,

Re: [computer-go] Kinds of Zobrist hashes

2009-12-09 Thread Álvaro Begué
2009/12/9 Christian Nentwich christ...@modeltwozero.com: On Tue, Dec 08, 2009 at 09:30:47PM -0500, Eric Boesch wrote: You can mathematically prove the two systems are almost the same, so there's no need to test.  Yes, this was my line of thought, but I wasn't sure if I'm not missing

Re: [computer-go] Kinds of Zobrist hashes

2009-12-09 Thread Mark Boon
On Tue, Dec 8, 2009 at 8:37 PM, David Fotland fotl...@smart-games.com wrote: I use two values.  I never even occurred to me to use three. I use one, it never occurred to me to use two :) At the time I'd never heard of Zobrist, but I used to use a single value for each point to look up Joseki.

[computer-go] Kinds of Zobrist hashes

2009-12-09 Thread Jacques Basaldúa
1. The 3 hashes: As Eric Boesch and Álvaro said, you can get the same codes as in the Black[], White[], Empty[] scenario using only 2 BlackXorEmpty[] and WhiteXorEmpty[] 2. What does make sense is making a difference between a POSITIONAL hash and a SITUATIONAL hash. The positional hash is the

Re: [computer-go] Kinds of Zobrist hashes

2009-12-09 Thread Álvaro Begué
On Wed, Dec 9, 2009 at 1:19 PM, Jacques Basaldúa jacq...@dybot.com wrote: 1. The 3 hashes: As Eric Boesch and Álvaro said, you can get the same codes as in the Black[], White[], Empty[] scenario using only 2 BlackXorEmpty[] and WhiteXorEmpty[] 2. What does make sense is making a difference

[computer-go] Kinds of Zobrist hashes

2009-12-09 Thread Jacques Basaldúa
Álvaro Begué wrote: The legal moves might be the same now, but they might be different after I perform a particular move. You are right. Looks like my solution is not perfect, but it works good enough. I have seen trouble, before I implemented it, because the transposition table identified

[computer-go] Kinds of Zobrist hashes

2009-12-08 Thread Petr Baudis
Hi! In most papers I've read, three-valued Zobrist hashes are used - per intersection, values for empty, black and white coloring [1]. I'm not clear on why is the empty value needed, however, shouldn't only black, white values work just fine? Is the hash behaving better with extra values for

Re: [computer-go] Kinds of Zobrist hashes

2009-12-08 Thread Don Dailey
The empty value is not needed. In some games it's easier to have it because it can be a simplification - everything handled uniformly for instance and it can avoid a conditional branch but I don't think that is an issue with Go. - Don On Tue, Dec 8, 2009 at 5:49 PM, Petr Baudis pa...@ucw.cz

Re: [computer-go] Kinds of Zobrist hashes

2009-12-08 Thread Eric Boesch
On Tue, Dec 8, 2009 at 5:49 PM, Petr Baudis pa...@ucw.cz wrote:  Hi!  In most papers I've read, three-valued Zobrist hashes are used - per intersection, values for empty, black and white coloring [1]. I'm not clear on why is the empty value needed, however, shouldn't only black, white values

RE: [computer-go] Kinds of Zobrist hashes

2009-12-08 Thread David Fotland
: [computer-go] Kinds of Zobrist hashes Hi! In most papers I've read, three-valued Zobrist hashes are used - per intersection, values for empty, black and white coloring [1]. I'm not clear on why is the empty value needed, however, shouldn't only black, white values work just fine