Author: Uri Blass
Date: 04:08:35 09/03/03
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On September 03, 2003 at 04:39:14, Bo Persson wrote: >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. I am still not sure about it. After all it is not a normal move. I think that for comparison reasons it may be better if I start with resetting it because today what I do is similiar because I found no repetitions when one position was before null move and another position was after null move. I think that the reason is that after null move when I check for repetition then the positions that I remember after null move are position with white to move and the positions that I remember before null moves are positions with black to move(the point is that I compare difference of 2 plies in the history moves and difference of 2 plies when I do not count null moves means difference in the side to move). In theory there may be a repetition when 2 null moves are between the identical positions but at least in the opening position I do not find it even after 20 minutes of search. Uri
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