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Subject: Re: a question to Tord about detecting threats in null move

Author: Uri Blass

Date: 15:21:33 10/03/03

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On October 03, 2003 at 17:34:56, Christophe Theron wrote:

>On October 03, 2003 at 15:36:22, Mridul Muralidharan wrote:
>
>>
>>You misinterpreted me.
>>
>>On October 03, 2003 at 14:51:24, Uri Blass wrote:
>>
>>>On October 03, 2003 at 13:38:54, Mridul Muralidharan wrote:
>>>
>>>>Hi,
>>>>
>>>>  I was a bit taken aback by these declarations :
>>>>
>>>>On October 03, 2003 at 12:47:23, Uri Blass wrote:
>>>>>I prefer even not to care about using hash tables for pruning because my
>>>>>experience told me that I cannot get significant gain there easily
>>>>
>>>>Hash table not giving you pruning ? I suspect a bug in your hashkey -
>>>>nothingelse.
>>>>Or maybe it is the easily that is operative word ?
>>>>I think there are a lot of open source programs that you can refer to and
>>>>correct your bugs with - crafty , GNUChess , etc , etc.
>>>>Might help to get this right.
>>>
>>>I do not like to copy from other sources.
>>>I found that instability helped me to do my program significantly better.
>>>
>>>If I delete it in order to be able to copy from other programs then I may need
>>>to start by doing it significantly weaker.
>>>
>>
>>I did not mean - "copy" here.
>>Rome was not built in a day. What I meant is :
>>Look at their implementation - check yours. Find any obvious bugs.
>>I seriously suspect that there are - since hashtables not only help in pruning ,
>>but massively help in move ordering.
>>If you can afford to make these statements - then your impl is horribly full of
>>bugs.
>>
>>As far as "instability helping" - I'm really not sure what you mean by this. As
>>far as I know - everyone , including me , tries to reduce instability so that
>>search is more stable requiring minimal search tree.
>>Wild extensions , unstable pruning , etc may help you in solving test suites
>>better and faster - but in real world games , it will suck badly.
>>
>>
>>>>
>>>>
>>>>>(I have a lot
>>>>>of stuff that means that pruning or extension is not defined only by the
>>>>>position).
>>>>
>>>>Where ever possible , I try to make the search behaviour as relevent to the
>>>>current position as possible and not rely on past search.
>>>>Why do you want to do the opposite ?
>>>
>>>because the opposite gives me some advantages.
>>
>>test , test , test - dont assume.
>>like my collegue says : When you AssUMe , you make an Ass of U and Me ;)
>>
>>>Movei has its chances against every program inspite of having bad order of moves
>>>and bad extensions and bad pruning.
>>>
>>
>>acceptance is the first step to improvement !
>>
>>>I believe that I can get above Crafty level if I improve order of move
>>>extensions,pruning and evaluation.
>>>
>>>Movei already has its chances against Crafty but today crafty is significantly
>>>better.
>>>
>>>There is a lot to improve and the main problem is programming.
>>>
>>>Uri
>>
>>
>>AFAIK movei is not smp - so no point in saying search here :)
>>SO , other than move ordering , eval and pruning : what else is left ? interface
>>code ? ;)
>>anyone can get to crafty level or higher - IF you are willing to put in the
>>effort and scientifically research.
>>All the best - wishing to see a better Movei and a more scientific Uri :)
>
>
>
>You are talking without knowing Uri, obviously.
>
>You are also talking about commputer chess without really knowing, I fear.
>
>Uri has been talking with us about chess programs for a long time without
>writing one. So at the begining he came with ideas that were not really
>relevant, or not exactly to the point.
>
>What I like about Uri is that at some point instead of keeping talking about the
>subject he has started to write his own chess program. I also know that he has a
>very scientific, objective approach in what he does.
>
>So if I was you I would not give Uri beginners's advices like "test, test -
>don't assume". Because as far as I know that's exactly what he is doing.
>
>I also believe that Uri is right in not trying to get too much inspiration from
>other chess programs.
>
>I think you should refrain from giving lame advices to Uri and tell us instead
>about your achievements as a chess programmer.
>
>
>
>    Christophe

Thanks for the support.
I believe that I did not implement most of the ideas that I had before writing a
chess program.

There are things that I did not try not because I believe that they are not
productive but because they are not simple to implement and I prefer to think
about implementing more simple things first.

About testing I can say that in a lot of cases I am not sure if the program is
better after a change that I accept but at least I am sure that it is not
significantly worse.

Uri



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