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

Author: Stuart Cracraft

Date: 21:34:48 03/06/06

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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



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