Author: William Bryant
Date: 15:26:33 04/03/99
I recently ran (for the first time) the LCTII test suite against my program in
two forms, one with a PVS search and one without. The version without scored
better in a few positions. At no point did the PVS code make it to a deeper ply
in the 10 minute time frame than the non-PVS search.
(Score of 2090 for PVS to 2120 without PVS).
I do not have Null moves implemented yet.
I know PVS is very sensitive to move ordering. I am sorting moves as follows.
1. Hash Table Moves
2. PV Move (if not the same as Hash table move)
3. Captures and Promotions
4. History moves
5. All other moves
I do not have killer moves added yet
My questions are:
1) Does null move pruning help PVS work better.
2) Does this suggest a bug in my PVS code (listed below).
3) Am I missing something else?
Thanks in advance,
William
wbryant@ix.netcom.com
Note: this code is only in the search_Root function not in the search function.
//****** PVS Search
if (firstMove){ //following the pv so don't change anything
x= -search(-beta, -alpha, depth-1);
firstMove = false;
}
else{ //try a PVS search
x= -search(-alpha-1, -alpha, depth - 1);
if ((x>alpha) && (x<beta) && (!OutOfTime)) {
gPVSResearch ++; //research
x= -search(-beta,-alpha,depth-1);
}
}
//******
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