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Subject: Re: Hitting the researchwall

Author: Carmelo Calzerano

Date: 12:12:54 08/24/01

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On August 24, 2001 at 09:20:52, Robert Hyatt wrote:

>On August 24, 2001 at 06:30:39, Carmelo Calzerano wrote:
>
>>On August 24, 2001 at 04:31:27, Tony Werten wrote:
>>
>>>My program searches for 4 minutes, gets to 14 ply (or whatever), makes a move,
>>>takes a pondermove and starts pondering.
>>>Now the first 12 ply are taken from the hashtable (<1 sec ) but it starts an
>>>(almost) uninformed 13 ply search from which it is never going to return in the
>>>allocated time, so it's just taking the best move it had from the previous
>>>search, which is costing me plydepth. (and games )
>>
>>Why almost uninformed? You should have at least the PV from the previous
>>searches, which combined with hash table information should be exactly
>>what you need. Just get the 14 ply search PV, remove the first two moves
>>from it (the move you actually made, and the move you are pondering on)
>>and you'll have a 12 ply search PV to guide the 13 ply search.
>
>If you get an EXACT hash hit on the first move, you won't have a PV.  If you
>try to reconstruct the PV from the hash table, it might not be there due to
>overwriting issues...
>
>Internal iterative deepening is the solution to this problem.

You are right, but if I understood it correctly the question was a little
bit different: IID helps in the general case (missing a best move when
searching along the PV), while my answer was about the specific problem
Tony pointed out. But maybe I misurderstood the question.

Regards,
Carmelo







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