Author: Dann Corbit
Date: 20:59:59 03/06/06
Go up one level in this thread
On March 06, 2006 at 23:55:17, Dann Corbit wrote: >On March 06, 2006 at 23:39:36, Stuart Cracraft wrote: > >>On March 06, 2006 at 22:47:18, Dann Corbit wrote: >> >>>On March 06, 2006 at 22:13:56, Stuart Cracraft wrote: >>>[snip] >>>>Discouraging Dan. Discouraging. >>> >>>Suppose that you are 3 lines away from approximately the same result. >>> >>>BTW, I have had a crafty version score 300/300 with the same time controls. >>> >>>The only difficult problem in this set is WAC.230. >>> >>>I think that WAC is a great set to start working with on a chess engine. >>>After a few months you are going to graduate to something tougher. >>> >>>I guess that there is some simple bug that is costing you 80% or more of the >>>misses. >>> >>>It sounds like an advanced engine from the things I have read so far. >>> >>>I think I saw a list of the missed problems by your program. I guess that I may >>>see a theme problem when I go over them. >> >>Thanks - I look forward to those comments at your availability. >> >>I reran the whole 300 suite at 10 seconds each this evening, >>due to Bob's comment, and pulled the failed 29 (Bob failed 9 >>I believe.) >> >>Then I reran against just my 29 and found that only 24 failed the >>second time, at the same time control. >> >>This tells me that there is something about the test that is not >>reproducible, based on either the ordering of the tests in the suite >>or aspects being carried from test position to test position (hash >>tables, history heuristic, etc.) I am not sure what it is. >> >>To test this theory, I took the 29 that failed of which only 24 failed >>the second time and reversed them so that the last came first and retested. >>This time 4 of the 29 were solved instead of 5. This difference of one is >>too small to claim an ordering result for just 29 position sample size. >> >>Still this indicates that instead of failing 29 I am failing 24-25 >>and I am not sure what would cause it. Before every iterative deepening >>ply 1 search, I clear out the history heuristic table, the hash tables, >>and the principal variation arrays. >> >>Still that is only 4-5 more leaving 24-25 left, arguably 15-16 if one >>wants to aspire as high as Crafty. >> >>I am at a total roadblock on the subject. As I mentioned, I will be >>putting money where my mouth is and making a signficant donation to >>the board sponsors for guidance to a solution of gaining say another >>10 right above my current 271 at 10 seconds. (Hopefully that's legal >>here.) > >This sounds like a bug. >If you analyze a new position, you should definitely clear the hash table >between analysis runs. Note: A good way to know you should clear the hash is if the node you are given to analyze is not a pv node in the hash table. If the node is a PV node in the hash table, then don't bother to clear it. >If the results are not exactly the same time after time, >then there is a bug (unless you introduce randomness or use floating point for >your eval or other odd things like that). >Memory overwrite or hashing or something like that may be at fault. > >Do you have a way to compute the hash signature from scratch instead of >incrementally? If so, I suggest doing a debug build that for every make-move >computes the hash completely from scratch and then compares the hash signature >with the incremental hash signature created by make-move. If anything does not >match, you may have found the culprit. > >Also, valgrind or some other memory checking tool might prove valuable. If your >code is ANSI C, you could run SPLINT against it. > >If you are not opposed to sending me a copy of your code I will take a look at >it for you.
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.