Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Time control legend

Author: Dave Gomboc

Date: 22:46:04 05/15/98

Go up one level in this thread


On May 15, 1998 at 16:53:14, Robert Hyatt wrote:

>On May 15, 1998 at 10:40:52, Dave Gomboc wrote:
>
>>On May 14, 1998 at 08:57:46, Vincent Diepeveen wrote:
>>
>>>... could be true. This means [Fritz] simply has no knowledge about what
>>>to exchange. This is also the big weak point of Rebel.
>>>
>>>Ed schroeder states here that he is relying on leaf evaluation.
>>>In that case, rebel doesn't have code about what pieces to
>>>exchange.
>>>
>>>Main point is that you may not evaluate the exchanges. You should
>>>look to the material that you keep afterwards. So the resulting
>>>position.
>>>
>>>I dunno why Rebel+Fritz+genius and some others
>>>are so horrible in these exchanges, but my first guess was piece square
>>>tables. Now i say: perhaps mobility is a reason too.
>>>The common thing of all these programs compared to Crafty, Zarkov, Diep
>>>and some others is that they lack mobility terms.
>>
>>Crafty only has mobility for bishops at this point.  I think Ferret is
>>not using a general mobility term either, if I recall correctly.  The
>>trend has been to move away from measuring mobility (well or badly), not
>>toward it.
>>
>>Dave Gomboc
>
>
>
>Correct, but not for the reasons you'd suspect... IE it has nothing to
>do with performance, since mobility costs practically nothing in my
>code.
>But, in most cases, particularly for the queens and rooks, mobility is a
>"result of winning", not necessarily a "cause of winning."  My very
>first
>eval in Crafty was 100% mobility.  It didn't work well.  Now, other
>terms
>replace mobility with more useful information, such as rooks on
>open/half-
>open files... this increases mobility, but is a measure of *useful*
>mobility
>rather than general mobility.  The queen is a good example, that often
>if
>you move it to the square where it has the most mobility, that square is
>"gross"...  from a strategic point...
>
>For bishops, I haven't done much yet, which is still on my todo list, so
>mobility is still used there.  But for all the other pieces, I believe
>there
>are *better* positional terms than simple mobility...

Actually, I expected what you said, :-) because you've said it in
previous posts.  Mobility seems to be one of those things that come up
every three months or so.

Dave Gomboc



This page took 0.05 seconds to execute

Last modified: Thu, 07 Jul 11 08:48:38 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.