Author: Stuart Cracraft
Date: 20:35:15 01/14/06
Go up one level in this thread
On January 14, 2006 at 17:27:00, GeoffW wrote:
>Hi Stuart
>
>>Where is this Winboard forum?
>
>http://wbforum.volker-pittlik.name/
** Thanks
>
>You might like it as there is a specific programming sub forum
>
>>
>>Also - why haven't they turned to Arena?
>>
>Lots of old loyal fans for Winboard, and apparently Winboard is more robust when
>used with the Internet chess servers. I only use Arena myself, but i know that
>Alessandro is updating Winboard to add some interesting new stuff
>
>
>>Arena doesn't have ability to play a program on ICS/FICS automatically?
>It does have this feature, it basicially works but is a bit buggy from what I
>recollect other people saying
>
>Changing subject, your post a while back where you posted a snippet of code for
>late move reductions, any chance you could repost it please as I cant find it
>now.
>The reason I ask is I added the same trick to my prog, it seemed great at first
>as it reduced node count hugeley, now I have played a few games with it though
>it is badly reducing strength
I have this in my main PVS loop (after the first move has been searched
before the loop.) The legals includes the pre-loop move. So I have to have
searched 4 or more legal moves, not pseudo-legal, before I can start tossing
moves out as long as no prune is set, no extensions and no reductions.
#ifdef LATEMOVEREDUCTION
// late move reduction, i.e. the poorly named history pruning, follows.
if (prune == 0 && extension == 0 && reduction == 0 && legals > 3 &&
!(sml[mvi].cap!=0||sml[mvi].pro!=0||hheuristic[stm][sml[mvi].from][sml[mvi].to]>0))
{
extension=-1;
}
#endif
>
>Have you got some results now as to the effect it had on your program ?
>
> Regards Geoff
Here's the test I did to respond to your question:
with Late Move Reduction:
1 second per move, 300 Win-at-Chess position, score=206.
without Late Move Reduction:
score=204
I know this is too close to call because it is < 1% difference.
At 5 seconds per move, the difference was 2% in favor of LMR.
But, and this is the big thing, I've wanted to call my program
"selective" for a long time - and now I can. Sounds petty, but it's fun.
Stuart
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