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Subject: Re: Chess program improvement project (copy at Winboard::Programming)

Author: Dann Corbit

Date: 16:29:39 03/07/06

Go up one level in this thread


On March 07, 2006 at 19:15:05, Stuart Cracraft wrote:

>On March 07, 2006 at 15:38:40, Robert Hyatt wrote:
>
>>On March 07, 2006 at 00:34:48, Stuart Cracraft wrote:
>>
>>>On March 07, 2006 at 00:31:45, Dann Corbit wrote:
>>>
>>>>On March 07, 2006 at 00:27:43, Stuart Cracraft wrote:
>>>>[snip]
>>>>>Very interesting indeed. A clever test.
>>>>>
>>>>>If one's results do not rotate approximately as described
>>>>>for the four positions and you say the evaluation is an
>>>>>issue, what kinds of evaluation issues have you seen that
>>>>>could explain it?!?
>>>>
>>>>The most common thing that I see is something that is good for white being
>>>>counted as positive for black also on the evaluation.  Often, when we are
>>>>writing the eval, we are thinking from the perspective of white. And so if we
>>>>are not very careful, we may invert the sign of some evaluation component and
>>>>count something that is good for white as something that is good for black (or
>>>>vice versa, though the reverse is seen less often for some reason).
>>>>
>>>>There are, of course, many other possible causes besides that.
>>>
>>>A good point. I try to avoid that by always doing things from the
>>>side on move, almost always. There are a few in there however with
>>>respect to white and black specifically, but they are then folded
>>>together with the stm variable and stm^1 which translate to white/black
>>>or black/white depending on who's on move. I could try this: rerun
>>>your rotation test with successively less in the evaluation table
>>>until nothing but material and see what happens.
>>>
>>>Stuart
>>
>>Let me toss in that we are talking about apples and oranges at the moment.  WAC
>>is not about evaluation very much.  It is mostly about finding mates or
>>significant material wins, and there your evaluation isn't much help so long as
>>it knows how to add up the values of pieces...
>>
>>getting WAC solved quickly is really about tactics, extending the right things,
>>and trying to avoid extending the wrong things...
>
>But an asymmetric evaluation function could unbalance the search
>sufficiently to cause an issue, no?

I think we should just eliminate one variable at a time.  When we are done, what
is left will be the answer.



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