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Subject: Re: Fine #70

Author: Michel Langeveld

Date: 08:32:08 10/16/03

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On October 16, 2003 at 09:03:42, Ernst Walet wrote:

>On October 16, 2003 at 06:45:31, Michel Langeveld wrote:
>
>>On October 15, 2003 at 15:09:32, Michel Langeveld wrote:
>>
>>>On October 15, 2003 at 13:21:20, Gerd Isenberg wrote:
>>>
>>>>On October 15, 2003 at 12:37:43, Michel Langeveld wrote:
>>>>
>>>>>[D]8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - -
>>>>>
>>>>>This position really bothers me ... and bothers nullmover...
>>>>>nullmover takes a really long time to see that the pawn can be really won.
>>>>>
>>>>>At ply 23 we see the keymove Kb1, but it needs 26 ply after 6 minutes we see
>>>>>that Kb1 wins a true pawn.
>>>>>
>>>>>The hashhit percentage is only 3%.
>>>>>The FH is only 30%
>>>>>
>>>>>Do I have to be worried ... or is this still all normal?
>>>>
>>>>Hi Michel,
>>>>
>>>>no, absolutely not. There is something wrong with your hash-table.
>>>>Hash-hits in IsiChess are about 70-80%, exact hits ~25%.
>>>>Depth 30 with >3.00 score after 0.5 seconds on Athlon XP 2.6+.
>>>
>>>Thanks for the hashnumbers ... I calculated my hashhits wrong.
>>>I casted to an int ... and this made it go wrong because the hashhit
>>>counter is bigger as 32 bit. I cast it now to a double and I hit around 50%
>>>I will calculate the exact hits also.
>>>
>>>>I'll hope you don't fix this severe bug until saturday ;-)
>>>
>>>Yes I hope to fix it also :-)
>>
>>The problem is complicated ... and all things in Nullmover seem to be correlated
>>with not finding this move: hash, hashreplace algoritm, evaluation,
>>moveordering, lazy evaluation.
>>
>>In order words the error is not one thing alone but a sum-up of things that
>>works in the most of the positions but sub-optimal in others. And in this
>>particulair position it ends up in horror.
>>
>>I found out that if I use:
>>- an always replace algoritm
>>- take away my lazy evaluation
>>
>>I find Kb1 on ply 22
>>I get 33 ply almost instantly
>>I get 40 ply in a minute with a nice score of  +2.38 score on Kb1 and Kxf5 in
>>the PV.
>>
>>The problem with always replace is that on WAC I score only 210 out of 300 with
>>2 seconds a position and else 265 / 300 on 2 seconds......
>>
>>still puzzling
>
>
>You must be happy, two days before Leiden :)
>
>See you there..
>
>A passionate observer ;)
>
>Ernst.

Yes it's hard work ... long evenings ... and less sleep... :-) But I have a
version of Nullmover that plays stronger as last time in Leiden. About 100 elo.
Not a big deal but enough to have some fun again.



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