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Subject: Re: Reasons for attending

Author: Uri Blass

Date: 03:27:38 01/09/03

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On January 09, 2003 at 05:51:47, Richard Pijl wrote:

>
>>>>I can announce that movei is not going to participate.
>>>>
>
>Which is entirely up to you of course
>
>>>>It has enough tournaments that it participates and I see no need to participate
>>>>in another tournament(it is better if I spend more time on fixing it and not on
>>>>looking at more games of it).
>
>As I have participated in two tournaments (both in Leiden) I can assure you that
>playing in those tournaments while watching the games will give you:
>- Time to really think about every move your engine plays, question it and think
>of ways to improve
>- Comments of opponents/bystanders about what the opponent/bystanders see in the
>position.
>- General hints and tips by opponents/bystanders
>
>During (!) the last tournament (Dutch-open) I solved two bugs after round 1, one
>more after round 3, and a whole bunch of bugs after round 6 (which was a whole
>week). In round 8 Baron gave away a draw against Tiger (!), and in round 11 it
>drew against the King. I'm very sure I would not have accomplished that without
>the things you're forced to look at.
>
>Solving bugs is still the best way of improving your engine ...
>
>>>
>>>I hope you will reconsider participating.  I have found that the intensity of
>>>tournament plays brings more bugs to light than any other way.
>
>Agreed!
>
>>>Also, new ideas for improvements seem to follow from tournaments, perhaps
>>>because the author is more focused on the games.
>>
>>Movei is playing in enough tournaments.
>
>Even if you get the PGN _with_ the PV line, you still do not get the amount of
>information that you will get when watching the game being played. Like moves
>considered, fail-low/high sequences, score development in iterations etc.
>>
>>I do not see the big advantage from playing in another tournament.
>>It is better if I work about what I need to do.
>
>There aren't many tournaments like this, so I usually grab the chance of
>participating when I have the chance.
>The todo list will be long anyway no matter how much you work on your engine.
>
>>
>>There are a lot of free engines that movei can play against them.
>>I do not understand why the ICC tournament can help me more than games
>>that I get from other sources when the number of the games that I get from other
>>sources is clearly bigger.
>
>It's not quantity that counts, but quality. Sometimes you need only one game or
>position to find a lot of bugs. It's just a matter of careful watching what the
>engine does. There is more to it than just the move it plays!
>
>>
>>Games did not help me to find that movei use numextensions[-1] in the first
>>iteration
>>checkingbounds helped me to detect it.
>
>You should use all methods at your disposal to find bugs. Watch games being
>played is just one method. Bounds checking is another method. Also compiling
>your code with all warnings turned on can turn up bugs (type conversions to name
>just one).
>>
>>For some reason when I use test postions I find that the number of nodes is the
>>same even after correcting the error.
>
>Then you used the wrong testpositions for testing the improvement :-)
>
>>There was also another error(not deterministic error) before the error of
>>numextensions[-1] but for some reason I cannot reproduce it now.
>
>Games will turn up a lot of those, and even more when you're start doing
>cut-offs based on the transposition table.
>Non-deterministic errors in test positions are IMO pointing to uninitialized
>memory or out of bounds memory and most of those should be found with a bounds
>checker.

The problem is that the non deterministic error happened only when I used bound
checking and not in normal run of the program.

Here is the descreption of the error that cheking bound told me:

Subscript Overrun: Array index value 44 exceeds array index limit of 8.

The problem is that no array that I used at the same time had dmenesion of 8 and
that the error now cannot be reproduced.


>
>>I believe that discussions here can help me more than games to get rid of these
>>errors.
>
>You will have those discussions online during tournaments ...
>
>>The main problem of movei except it is not bugs but lack of knowledge.
>>I looked in a lot of previous games of movei and I do not believe that new
>>tournaments are going to help me.
>
>If you have bugs in search or eval, correcting those will get you more than
>adding more knowledge. The main jumps in strength of the Baron are caused by
>solving bugs, not by adding new knowledge ... (adding knowledge usually
>introduces new bugs :-) )
>
>Richard.

It depends on the bugs
I try to be careful about it and for every code that I add to add code to check
for bugs.

The baron has clearly more knowledge than movei(that until today have no
knowledge about king safety or pawn structure) and I plan to add knowledge about
pawn structure but I will be careful to give bonus only in clear cases

The first step that I plan to do is to give bonus for passed pawns only if it is
protected by a pawn but I need first to update my bitboard for pawns when I make
and unmake moves and check that I do it correctly and only later when I have the
bitboard for pawns correctly I may continue and define the bitboard for
protected passed pawns.

Uri



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