Author: James Robertson
Date: 16:12:42 04/03/99
Go up one level in this thread
On April 03, 1999 at 18:26:33, William Bryant wrote:
>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);
> }
>}
>//******
The code looks correct; but I use it everywhere, not just in the root.
James
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