Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Futility Pruning off?

Author: Tord Romstad

Date: 15:25:54 01/21/04

Go up one level in this thread


On January 21, 2004 at 14:59:23, Robert Hyatt wrote:

>On January 21, 2004 at 12:45:59, Tord Romstad wrote:
>
>>On January 21, 2004 at 05:02:37, Robert Allgeuer wrote:
>>
>>>Do I conclude correctly that futilty pruning is off? Is there a specific reason
>>>for that?
>>
>>Possibly that it simply doesn't work very well?  The idea has always looked
>>dubious to me, and my own experiments confirm this.  There is a speedup, but
>>it is not worth the risks.
>>
>>As always, the results may vary from engine to engine, but I suppose Bob has
>>found that it doesn't work for him either.
>>
>>Tord
>
>
>Correct.  I didn't like it myself after lots of testing.  It looks good on
>test sets, but you don't win games by doing well on test sets.

That's precisely what I found, too.

In general I am very sceptical about pruning schemes which prune moves before
they
are made.   At that time, we simply don't know enough about the moves to be able
to prune safely.  I do some fairly aggressive forward pruning in my engine, but
I always
prune after the move has been made and the resulting position has been
evaluated.
This is of course more expensive, but also much less risky.

Tord



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.