Author: Carlos del Cacho
Date: 13:34:53 01/27/01
Go up one level in this thread
On January 27, 2001 at 14:30:18, Severi Salminen wrote:
>Hi!
>
>I made a few test games between a version of my engine using SEE and another
>using just MVV sorting. I played only a few (24) games and time control was
>5min/G and in 8 games 1min/G. The result was 12-12! Is this possible, normal, or
>do I have a bug? I would have guessed that the SEE version had beat the hell out
>of the other but that never happened. It seems that SEE slows things down a lot
>and the net result seems to be that it searches equally deep compared to the
>other version. Has anyone here measured the true benefit of using SEE? Could you
>show me positions in which SEE makes a big difference or could you run self-test
>games between two versions of your program? Are there positions where SEE hurts
>searching? I really like to know if SEE is worth it? I have a relatively slow
>computer (300Mhz Celeron, Crafty running at 80KNPS) so could time control and
>overall speed have influence on this?
>
>Any comments are welcome!
>
>Severi
Just a quick test. Two runs on WAC 5 sec/problem:
- SEE pruning in Quiescent Search: 270
- without it: 246
So it is definitely a win for my program (Pepito).
The only difference between these builds was commenting out these lines:
val = SEE(pos_stack->jug);
if (val < 0)
continue;
val += MARGEN_QUIES + pos_eval;
if (val <= alpha)
continue;
But you should note that I try not to call the SEE function whenever possible.
If I can get a cut with pos_eval + mat_gain I give up this capture. Another
question is if SEE is profitable in normal search. I also it there but kicking
it out would be a bit more difficult so I haven't tried yet :-). At the same
time captures are generated I assign them their MVV/LVA scores. Then I try
captures with positive scores and when this gets below zero I call SEE for
remaining moves. Losing ones are searched after all non captures. I'm not really
sure about the gains here so I'll give it a try...
Greets,
Carlos
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.