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Subject: Re: PV code?

Author: Charles L. Williams

Date: 10:04:48 05/02/99

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On May 02, 1999 at 12:14:55, Pham Hong Nguyen wrote:

>I saw in the "PV Search" message of Peter that PV code like this:
>
>       move PV[MAXPLY] [MAXPLY];
>       ...
>       PV[ply][0] = bestmove of this node;
>       for (ix=1; PV[ply+1][ix-1] != 0; ix++)
>	   PV[ply][ix] = PV[ply+1][ix-1]
>       PV[ply][ix] = 0;
>
>
>I tried other way like this:
>       move PV[MAXPLY];
>       ...
>       PV[ply] = bestmove of this node;
>
>And I found that some time my code is better, some time is worse than first. So
>It makes me very confusion which is the best.
>
>Did I do some thing wrong? Could someone give me some suggestions?
>
>Thanks in advance,
>
>Pham Hong Nguyen



I might not be entirely right about this, but I suspect that the best moves deep
in the search are overwriting the existing PV.  If what the search believes are
the best moves turn out to be wrong, then the PV has been clobbered for nothing
and is not retrievable.  The idea of the two dimensional triangular array is to
keep the search in progress separate from the PV.


Chuck




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