Author: Ricardo Gibert
Date: 08:37:28 03/19/03
Go up one level in this thread
On March 19, 2003 at 09:54:02, Uri Blass wrote: >On March 19, 2003 at 09:29:04, Matthias Gemuh wrote: > >>On March 19, 2003 at 08:28:02, Ricardo Gibert wrote: >> >>>On March 19, 2003 at 06:33:01, Matthias Gemuh wrote: >>> >>>>I decided to stop chess programming but even the latest version of my program >>>>sucks. How can I quit in peace? >>>>It calculates this attack information (bitboards of attackers to 64 squares) >>>> BITBOARD AttacksTo[64] >>>>from scratch at each node. I tried to do this incremementally and it quickly got >>>>messy and buggy because of sliding pieces, castle, en passant. >>>>How do you attack attack boards (even the conventional type)? >>>> >>>>/Matthias. >>> >>> >>>Let me share a couple of observations I have made concerning the development of >>>amateur chess programs. >>> >>>The 1st big mistake I see repeatedly is being in too much of a rush make their >>>programs strong by adding "fancy stuff." A very simple program can be fairly >>>strong (> 2200 elo). You just need to get the fundamental things to work right >>>*first*. Gerbil is a good example of what is possible with a reasonably simple >>>program (about 2400 ICC rating). Don't layer the "fancy stuff" on top of the >>>incorrectly implemented fundamental stuff. >> >> >>Hi Ricardo, >>I, indeed, do layer "fancy stuff" on junk :). >>That explains why my prog scores a miserable 260/300 WAC at 5sec/pos on 1.8GHz. >>BTW, my prog (BigLion) is at least 5 times slower than Gerbil, but equal in >>strength at 1 minute/move. >>If I should ever come back to chess programming, I think I would follow your >>instructions. I just want to correct my fancy stuff now (my evaluation function >>depends heavily on it). >>Thanks, >>Matthias. > >Did you try to spend time to search for the reason that your program is so weak >in WAC? > >If you find a position that other programs are more than 100 times faster than >biglion then it may tell you about bugs in your program. > >Movei solved 276 position on WAC in 1 second on 1GHz so I do not believe that >lack of speed is the only problem of biglion. > >I do not think that speed optimization are bad idea. >speed optimization can also tell you about bugs in your program. Let me clarify what I mean by "speed optimizations." A program with low NPS *can* be an indication of improper implementation. NPS should be at a reasonable level. Rectifying such bugs I do not consider a "speed optimization", but rather simply "bug fixing." Ditto for time to depth, etc. I should have said, "Remember: Think simple, clear and *correct*." > >If you do something that should do the same thing faster and it does not do the >same thing faster then you can discover that the bug is in your program and not >in the speed optimization. > >I discovered some minutes ago a bug in latest movei and it seems that the making >a move and undoing a move can change the evaluation of a position(the change was >very small and was only 0.05 pawns but I will investigate the problem). > >I tried to do my program faster by avoiding some makemove that I am sure that I >am going to prune later as illogical but in order to check if I have no bugs >I decided instead of making the move to have nodes++ with no move to see if I >get the same number of nodes. > >I found that I did not get the same number of nodes and the reason was that >avoiding make,unmake move changed the evaluation after 5377435 nodes by 0.05 >pawns and changed pruning decision(I still do not know the reason at this >point). > >Uri
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