Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: what do you update during null move

Author: Bo Persson

Date: 01:39:14 09/03/03

Go up one level in this thread


On September 03, 2003 at 03:26:59, Uri Blass wrote:

>It is something that I need to fix but before fixing it I prefer
>to read what other people do.

I think you should treat a null move just like a normal move, except that no
pieces are moved or captured.

>
>Today I update
>1)the side to move
>2)the ep array(I have instead of one global varaible an array of 3 numbers that
>gives me the en passant possibilities(square of the pawn that can capture and
>squares that it can capture) and maybe it is better if I compress it to one
>varaible and replace ep[0],ep[1],ep[2] by defines)
>
>I am also not sure if all my global varaibles is a good idea and it may be
>better to save the ep information only in the history information.
>
>3)A global varaible that is the zobrist key(maybe I should get rid of it and
>read the zobrist key from the history information something that is possible
>only after I change my makenull move)
>
>4)The arrays that are search dependent(for example the array that gives me
>information about the evaluation of every ply).
>
>I do not include these arrays in a struct and maybe I should do it.
>
>I do not update
>1)The fifty global varaible that tells me the number of plies
>from the last conversion and I am not sure how to update it after null move and
>if to reset it to 0 or to increase fifty by 1.

It is a move, and it is definitely reversible. I think you should probably
increase the count, and definitely not reset it.

>
>2)The history ply and all the arrays in the struct that are dependent on it.
>
>3)The zobrist array that is history dependent and is used only for checking
>repetition.

My hash key is not history dependent, more than that it is a function of the
current position. If you also include the path for getting there, I don't know
what that does.


Bo Persson



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.