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Subject: Re: Evaluation in Rebel

Author: Ed Schröder

Date: 04:21:38 01/07/03

Go up one level in this thread


On January 07, 2003 at 06:30:54, Uri Blass wrote:

>On January 07, 2003 at 06:20:15, Ed Schröder wrote:
>
>>On January 07, 2003 at 06:00:58, Uri Blass wrote:
>>
>>>On January 07, 2003 at 05:47:37, Ed Schröder wrote:
>>>
>>>>On January 07, 2003 at 05:05:31, Tony Werten wrote:
>>>>
>>>>>Hi Ed,
>>>>>
>>>>>your board tables seem to ignore xray attacks.
>>>>
>>>>xray attacks are done, it's only not mentioned as I thought it would be
>>>>self-understood.
>>>>
>>>>
>>>>>Is that because it doesn't matter too much, or because it's mainly used for move
>>>>>ordering ( so it's only less effective but not wrong ) ?
>>>>
>>>>I use xray also for evaluation, for instance for mobilty, king safety, so xray
>>>>must be done and in an accurate way, I will write a little about it in the
>>>>mobility section.
>>>>
>>>>Ed
>>
>>
>>>Hi Ed,
>>>
>>>I have 2 questions about the evaluation.
>>>
>>>1)Did you try to do incremental evaluation.
>>
>>I have tried it in the past, it was maddening, if you are in love with bugs,
>>self-torture and headaches then doing incremental evaluation is the right path
>>to go.
>>
>>
>>>I think that incremental evaluation may be faster than doing the full evaluation
>>>at every node until depth-1.
>>
>>It is faster of course, but don't hold your breath, you will have to restore
>>things too when climbimg back in the tree (decremental evaluation), meaning
>>things have to be done twice. On "incremental evaluation", you can of course put
>>all things on stack and just copy things back but that is also costly.
>>
>>
>>>The problem is that doing it without bugs is not easy espacially when you have a
>>>big evaluation.
>>
>>Yes, that's why I never finished the job, the second reason: it wasn't that much
>>faster.
>>
>>
>>>2)Did you check that your full evaluation is really productive if you assume the
>>>same number of nodes.
>>>I remember that when I tested personalities of Rebel I found that knowledge=500
>>>changes it's mind more often so it needs more nodes to finish the same
>>>iteration.
>>
>>Natuarally [Chess Knowledge = 500] beats [Chess Knowledge = 100] slightly based
>>on fixed depth, but it loses with a big margin using a normal time control,
>>remember the gain from Lazy Eval is over a factor of 3.
>>
>>Ed

>I know it but the interesting question is based on fixed number of nodes because
>my impression was that chess knowledge=500 needs more nodes to finish the same
>depth.

I think this is true, more QS nodes looks only natural when Lazy Eval is
excluded.

Ed


>Uri



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