Computer Chess Club Archives




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

Author: Uri Blass

Date: 12:57:03 10/03/03

Go up one level in this thread

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:
>>>  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 -
>>>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.

I already use them for that purpose.
I did not say that hash tables are not used.

>If you can afford to make these statements - then your impl is horribly full of
>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 test also in games.
>>>>(I have a lot
>>>>of stuff that means that pruning or extension is not defined only by the
>>>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 ;)

I test.

>>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
>>There is a lot to improve and the main problem is programming.
>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 ? ;)


I do not plan to use smp and I believe that the things that I mentioned can give
a lot.

>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 misinterpt me.
I did not decide that something is better based only on test positions.


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