Search found 17729 matches

by hgm
Tue Apr 24, 2007 12:37 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Two small in-register-lookups
Replies: 15
Views: 13786

Re: Two small in-register-lookups

You could of course replace the (sqr>>3^sqr)&1 by

Code: Select all

9*sqr & 8

for the purpose of making a boolean.

The multiplication could be implemented with a single LEA instruction:

Code: Select all

    movl  _sqr, %eax
    leal (%eax, %eax, 8), %eax
    andl  $8, %eax
by hgm
Tue Apr 24, 2007 9:51 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Two small in-register-lookups
Replies: 15
Views: 13786

Re: Two small in-register-lookups

Why would you want to use in-register lookups? Fetching such simple things from a memory table should be very competative, if not faster. I noticed that these out-of-order CPUs often perform very poorly if you only use registers, it seems that there is some internal bottleneck on how many registers ...
by hgm
Mon Apr 23, 2007 12:54 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Eden and my status
Replies: 12
Views: 11532

Re: Eden and my status

Instead, in my quest for knowledge in areas I have no clue about, I have ordered the Pico Edition of the XGamestation ( http://www.xgamestation.com/view_product.php?id=34 ), a "retro" game console that you can build yourself. I'm planning to write a chess program for it, just to see what I can achi...
by hgm
Thu Apr 19, 2007 4:02 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Eden and my status
Replies: 12
Views: 11532

Re: Eden and my status

Yes, I am also such a risk taker. Before going on holiday, I made a copy of the Joker sources on an USB stick. But if my house would have burned, that would not have prevented it from being lost.

I really should find a better solution to this, e.g. e-mail it to myself at work.
by hgm
Wed Apr 18, 2007 7:45 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Material imbalance evaluation
Replies: 10
Views: 12723

Re: Material imbalance evaluation

The most advanced theoretical considerations on ab-initio piece-value determination I have seen were by Ralph Betza. Apart from mobility, he also defined concepts such as 'forwardness' that seem to be important for piece strength. E.g. a piece that does only one diagonal step (Ferz) and a piece that...
by hgm
Tue Apr 17, 2007 8:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Material imbalance evaluation
Replies: 10
Views: 12723

Re: Material imbalance evaluation

I just did an interesting experiment in uMax concerning piece values. The standard version always used the 'classical' values 1,3,3,5,9. As uMax fails to correct for piece-square points of the captured piece, this makes trades of B vs N, B or N vs 3P, 2B vs R+P completely equal, and therefore often ...
by hgm
Mon Apr 16, 2007 10:26 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Material imbalance evaluation
Replies: 10
Views: 12723

Re: Material imbalance evaluation

I would be afraid that such an evaluation is very prone to systematic errors. For example, if you look at win prercentage of games where a Knight was sacrificed for two Pawns, you might conclude that the Pawns have a pretty good chance. But this would most likely be caused because these two Pawns wo...
by hgm
Sun Apr 15, 2007 4:50 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Test versions / private versions wanted for testing purposes
Replies: 20
Views: 19215

Re: Test ... / private versions ... Why SMIRF is different

Well, you should have a look at SMIRF. That is, why I still hasitate to have a UCI version of SMIRF (as I had done with SmirfMateUCI for a short time). There are some problems with common protocols: a) no support for Chancellor and Archbishop (playing, promoting ...) b) no support for different cas...
by hgm
Sat Apr 14, 2007 2:07 pm
Forum: Computer Chess Club: General Topics
Topic: Windows Vista: 32-bit or 64-bit?
Replies: 15
Views: 8247

Re: Windows Vista: 32-bit or 64-bit?

Hmm, it seems they don't want to sell me this computer with a 64-bit system, as they are not sure that 64-bit drivers exist for the video card it comes with. Buying an 'a la carte' PC from them with a simpler video card but otherwise the same hardware specs, and 64-bit Vista Basic in stead of 32-bit...
by hgm
Sat Apr 14, 2007 9:38 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Enhanced Transposition Cutoff
Replies: 6
Views: 7894

Re: Enhanced Transposition Cutoff

All my engines use IID, and I guess that this is automatically upward compatible with ETC: as in any node the search (after static move ordering) starts at d=1 (i.e. the replies to all moves are searched to QS level), it probes the hash in the daughter nodes for any position that can be reached. If ...