Search found 16875 matches

by bob
Sun Jun 03, 2007 12:54 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Observator bias or...
Replies: 51
Views: 54164

Re: Observator bias or...

Yes, for this reason testing at a fixed number of nodes and recording the ime, rather than fixing the time, seems preferable. But of course you cannot get rid of the randomness induced by SMP that way. For this reason I still want to implement the tree comparison idea I proposed here lately. This w...
by bob
Sat Jun 02, 2007 6:41 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Observator bias or...
Replies: 51
Views: 54164

Re: Observator bias or...

I am working on an ICGA paper hitting on this very topic. I'll make it electronically available once it has made it thru the review process. There are lots of places where randomness can creep in, but the main one is timing. Timing is just not that accurate, and at today's NPS rates, a few milliseco...
by bob
Sat Jun 02, 2007 6:37 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Observator bias or...
Replies: 51
Views: 54164

Re: Observator bias or...

I remember since testing with Kiwi that results with 100 games are very unreliable. It sometimes happen that a version gets a bad start but gets better at the end of the long test. On the other hand, I had a version reach 64% after 100 games and finish with a disappointing 50% after 720 games... I ...
by bob
Sat Jun 02, 2007 6:07 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Technical question about the Core 2 Duo and Mac OS X
Replies: 45
Views: 19751

Re: Technical question about the Core 2 Duo and Mac OS X

There are plenty of linux distros that run in 64 bit mode as well as the windows 64 bit version. Surely Apple has done this as well... My understanding is that Leopard (Mac OS/X 10.5) will run both 32 bit and 64 bit programs. Of course, the 64 programs will require a Core 2 Duo, Xeon Woodcrest, or ...
by bob
Sat Jun 02, 2007 6:00 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Comparison data of Crafty vs Rybka that I promised 2 days ag
Replies: 27
Views: 15568

Re: Movei added to Crafty vs Rybka comaprison data

yes. In fact, crafty has commands "flip" and "flop" to do that to the current position. "evtest" takes a FEN suite and does the sanity test using those commands. I ran all 4. all four reported a mate in 6. the scores were +2.18 and -2.18, + when it was black to move, - when it was white to move. So ...
by bob
Sat Jun 02, 2007 5:58 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Comparison data of Crafty vs Rybka that I promised 2 days ag
Replies: 27
Views: 15568

Re: Movei added to Crafty vs Rybka comaprison data

The involved both search and evaluation. Each row (we would expect) should have about the same solution time, and none of the rows should be worse than the first. These are the actual positions referenced in the test. For any solutions found, none should be worse than 32756 (though there are closer...
by bob
Sat Jun 02, 2007 5:56 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Comparison data of Crafty vs Rybka that I promised 2 days ag
Replies: 27
Views: 15568

Re: Movei added to Crafty vs Rybka comaprison data

One common "sanity test" I do in crafty is to feed it several thousand FEN positions, and have it evaluate each one 4 times. First, as the position is entered, then I flip the board vertically and swap the colors of all pieces, to give me a second position. I then flip the original position horizon...
by bob
Sat Jun 02, 2007 1:41 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Comparison data of Crafty vs Rybka that I promised 2 days ag
Replies: 27
Views: 15568

Re: Movei added to Crafty vs Rybka comaprison data

I am not sure I understand what you are doing. One common "sanity test" I do in crafty is to feed it several thousand FEN positions, and have it evaluate each one 4 times. First, as the position is entered, then I flip the board vertically and swap the colors of all pieces, to give me a second posit...
by bob
Sat Jun 02, 2007 1:36 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: pthread weirdness
Replies: 26
Views: 13117

Re: pthread weirdness

Pradu, It has to do with threads being asynchronus. In normal programing, the value in a memory location that a pointer points to is predictable because the programming is synchronized (the calling function waits on the called function to return). With threads, the calling function continues and ma...
by bob
Sat Jun 02, 2007 1:34 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: pthread weirdness
Replies: 26
Views: 13117

Re: pthread weirdness

I notice you have a loop iterating on i, and you are passing the _address_ of I to the new thread. By the time that thread executes, i will probably be at limit+1 which is almost certainly not what you want. Don't pass the address of that, pass the actual value. Note that the create function requir...