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Subject: Re: Pondering ("think on opponent's time")

Author: Uri Blass

Date: 00:31:58 11/12/02

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On November 12, 2002 at 02:06:21, Russell Reagan wrote:

>On November 12, 2002 at 01:14:36, Uri Blass wrote:
>
>>If we evaluate every possible move by having a thread for every legal move
>>then we have an idea about the second best move.
>
>Starting a thread for every legal move serves no purpose. Either you are going
>to set them all to the same priority, and you will be searching (say) 35 moves
>for 1/35th of the time you are pondering. Basically you're doing a search with
>no pruning at the root. So you're doing exactly what the opponent is doing, only
>you will never see what he sees because you're not pruning away moves at the
>root. When the opponent moves, you will have only searched the "right" move
>1/35th of the time. So if the opponent takes 3 minutes to move, you only
>pondered on the "right" move for a little over 5 seconds. In a lot of positions
>there will be a lot more than 35 legal moves, and that number of seconds keeps
>dropping. Basically you just wasted that 3 minutes.
>
>If you set the threads with one to run at a higher priority than the others, the
>one that you set with a higher priority is going to dominate all of the other
>threads since it will always be searching, so you might as well have just
>pondered on that one move, because not a single one of the other threads are
>going to result in anything useful.
>
>Russell

No

If I see better score in one of the thread with low priority
or if I see fail low in the main thread then I can increase the priority
of one of the threads that was given originally low priority.

Note that I do not use threads in movei but I guess that I can change the
priority of a thread during the search.

Uri




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