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Subject: Re: Effect of iterative deepening

Author: Frank Schneider

Date: 02:10:39 09/14/99

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Hi Bas,

On September 14, 1999 at 04:07:18, Bas Hamstra wrote:

>It seems I got PVS working. In comparison to simple alphabeta I get mixed
>results. I have seen positions where PVS does 20% less nodes than ab (starting
>position). However I have also seen (tactical) positions where PVS does do more
>nodes than ab. I am trying to find out how that's possible, but didn't have
>enough time.
>
>The impression is that pvs is just more sensitive to good moveordering than ab.
>
>I see that iterative deepening in Crafty. How important is it?
Iterative deepening is used in almost every program. The main effect is,
that by searching a position to depth n you get a very good moveordering
for the subsequent search to depth n+1.

There is also an additional technique called 'internal iterative deepening'.
It is a little enhancement which can save time in some (rare) positions.

Using iterative deepening is a must, internal iterative deepening is
nice to have.

Frank



>
>
>Regards,
>Bas Hamstra.



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