Author: Uri Blass
Date: 17:05:49 05/02/03
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On May 02, 2003 at 17:09:07, Geoff wrote: >Hi > >I would appreciate some advice on how I should procede in improving the chess >program I am working on. > >Currently it is very similar to TSCP. I will explain what I have changed and the >results I have got. > >Mod1) >Changed the Alpha Beta search to use use an Aspiration Window >This did give an improvement, reducing the number of nodes searched to get to a >given depth in most positions. >I did read that this could give search instabilites and might even cause lock >ups or crashes, I have not noticed this yet however > >Mod2) >Added a simple mobility function to the Evaluation. >This took my nodes per sec down from 500k/s to about 350k/s as I recalculate >every move for every piece again in the eval function. The playing strength >marginally decreased, probably due to the severe hit on speed ;-( No I guess that there is another reason. 500->350 is not a big reduction and mobility is important factor to evaluate. Maybe there is a bug in your evaluation or your mobility scores are too high(I do not know th way that you evaluate mobility). > >Mod 3) >Added a save of 2 killer moves at each ply and re-sorted moves before searching >This made hardly any difference in reducing the nodes searched to get to a given >ply. I assumed this lack of effect was due to the fact that it has already got a >history[64][64] array built into the code For me killer move helped significantly after history tables. > >I noticed that the good amateur programs get down to a depth of about 9 or 10 >where my program only manages 7 or 8 in a given time, so I guess I need to look >at things like Null moves and other complex search tricks ? > >Any advice as to what further mods I could do to gain the most improvement ? >Simple mods preferred first ;-) The most simple change is to increase the value of knight and bishop from 3 pawns to 3.3 pawns to prevent tscp to play bad trades of BN vs RP. Uri
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