Search found 161 matches

by vladstamate
Sat Mar 06, 2010 9:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Zero window TT entry
Replies: 12
Views: 1706

Re: Zero window TT entry

if returned_value>beta TTStore(beta, LOWER) return beta (I have a fail-hard implementation) Don't forget to fix this into "returned_value >= beta" if you haven't already. It is important for the algorithm. Sven Hi, Yes, I have changed all the returned paths of my root search, main s...
by vladstamate
Fri Mar 05, 2010 7:18 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Zero window TT entry
Replies: 12
Views: 1706

Re: Zero window TT entry

Hi, Yes, I was using fail-hard. I've spent some time now and changed my whole search to be fail soft. And as per advice in this thread I am adding the UPPER entry in the TT if no move can raise the alpha. At the moment I am not storing a move for this situation. However I do like the idea of having ...
by vladstamate
Fri Mar 05, 2010 12:37 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Zero window TT entry
Replies: 12
Views: 1706

Re: Zero window TT entry

Hi,

I meant that *I think* that

Code: Select all

TTStore(alpha, UPPER)
line should not be done if in a zero window search.

Regards,
Vlad.
by vladstamate
Fri Mar 05, 2010 12:35 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Zero window TT entry
Replies: 12
Views: 1706

Zero window TT entry

If I find myself in a zero window (-alpha-1, -alpha) search and no value above beta (inside that search) was found, do I still store the TT entry at the end before returning? Right now I do something like this: int search(alpha, beta, depth, ...) { for all moves returned_value = -search(...
by vladstamate
Thu Feb 25, 2010 6:15 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: TT hit/miss rates
Replies: 4
Views: 930

TT hit/miss rates

Hi, I am trying to see how way off mark I am compared with other engines in the TT hit/miss ratio. From the start position, looking until depth 8, this is what I get Cache usage: hits=16009(16.26%) misses=15367(15.61%) conflicts=67063(68.13%) hits - a value was found and returned misses ...
by vladstamate
Sat Feb 20, 2010 8:24 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Using the GPU
Replies: 9
Views: 2287

Re: Using the GPU

latency between the cpu and gpu add too much overhead to use it per node for evaluation and move generation. That is true. "Branchy" code is definitely a no-no on the GPGPU architectures. Since it is designed to run pixels really and it runs them many in parallel, same way it would run your threads...
by vladstamate
Sun Feb 07, 2010 5:53 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Standpat and check
Replies: 2
Views: 560

Re: Standpat and check

Right, That was good advice. I just did that in quiesce search: if in check, do not return beta or change alpha based on stand pat score and try to also generate the moves that takes us out of check, not only captures. That improved the engine noticeably. Plisk went from 400 to 427 in the 9 STS test...
by vladstamate
Sat Feb 06, 2010 6:20 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Standpat and check
Replies: 2
Views: 560

Standpat and check

Hi there, How should I deal with stand pat score calculation in quiesce search, in the situation where we are in check? Evaluations while in check are not reliable. So I cannot raise alpha or return beta (I have a fail-hard algorithm) based on the standpat score. So what do I do with it? Regards, Vl...
by vladstamate
Mon Feb 01, 2010 4:35 pm
Forum: Computer Chess Club: General Topics
Topic: XBoard and epd tournament
Replies: 4
Views: 989

Re: XBoard and epd tournament

Excellent! That is exactly the information I was looking for. Although I feel a bit ashamed for not going the extra mile and finding this for myself. However I am grateful for your help nevertheless!

Regards,
Vlad.
by vladstamate
Sun Jan 31, 2010 10:56 pm
Forum: Computer Chess Club: General Topics
Topic: XBoard and epd tournament
Replies: 4
Views: 989

XBoard and epd tournament

Hi, I currently use Arena when I want to test my engine against another engine using a set of predefined starting positions (such as Nunn 20). However I would like to use XBoard/Winboard for this (as well). Is it possible to tell XBoard to start each game picking up a position in a given epd file, a...