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Subject: Re: Improvements in BF makes my MoveGen suck =(

Author: Albert Bertilsson

Date: 06:09:06 06/27/03

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On June 27, 2003 at 08:51:09, Uri Blass wrote:

>On June 27, 2003 at 08:13:53, Albert Bertilsson wrote:
>>Just wanted to share my latest findings and warn you from making the same
>>mistake (or maybe I just point out the obvious).
>>I've always been proud to have a very fast movegen, doing perft calculations
>>very fast.
> I optimized the movegen alot, and always saw playing strength
>>increasing. I use a legal move generator and always saw the cost of verifying
>>legality to be minor. Lately however I've noticed that the engine performance
>>isn't that great (compared to other engines) inspite of the fast movegen. So I
>>started digging today and the numbers struck me as lightning...
>>As I've improved moveordering very much with hashtable/iterative deepening,
>>killer moves and history tables the effective BF is now much lower. The lower BF
>>now means that very few moves of all the generated ones are actually ever made.
>>This means that the cost of generating legal moves have increased incredibly
>>It's really anoying to notice that something you though was very good now is on
>>the list of improvements again =(.
>What do you mean?
>Do you plan to generate moves faster?
I haven't got any solutions to the problem yet, but in my case a faster movegen
at the cost of slower Do/Undo move would certainly give better performance. I
have some idéas but I have to get some time to test them.

>I plan to do it but in order to do it I need to calculate some arrays so
>my makemove is going to be slower.
>I am not sure about the total result(I guess that my perft is going to be faster
>when I finish the big modification but it is only a guess).
>I have already a perft generator that is 30% faster than the public version
>of movei(without hash tables) but I guess that it can be improved significantly.

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