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Subject: Re: Oh I ponder, ponder... What?

Author: Andreas Herrmann

Date: 10:14:56 08/14/01

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On August 14, 2001 at 10:29:32, Robert Hyatt wrote:

>On August 14, 2001 at 10:21:34, Andreas Herrmann wrote:
>
>>On August 13, 2001 at 22:54:34, Robert Hyatt wrote:
>>
>>>On August 13, 2001 at 22:20:18, Artem Pyatakov wrote:
>>>
>>>>Well, After tweaking my time control and some of my history settings, it seems
>>>>like I have pondering under control and it DOES help my engine go about one ply
>>>>deeper when it guesses the right move - thanks to people who responded to my
>>>>last post about pondering.
>>>>
>>>>I was wondering about a scenario, however, and about how people handled it in
>>>>their engine (just for fun, I will lay this out like a traditional math/physics
>>>>problem):
>>>>
>>>>Initial conditions:
>>>>Let's say the normal search produced a PV of length=1, because the very first
>>>>move produced a hit in the hash (transposition table).
>>>>
>>>>Problem:
>>>>Right now in my engine, I do not ponder in these cases, because I have no idea
>>>>what opponent move to ponder about (it's not in the PV).
>>>>
>>>
>>>
>>>
>>>I try two things:
>>>
>>>(1) probe the hash table.  If you get a hit, and it has a suggested best
>>>move, ponder that.  It isn't always good, but it is better than nothing.
>>>
>>>(2) flip sides, do a short search, and use the move that returns as the
>>>move to ponder.  Crafty calls this a "puzzling search" and you will see
>>>the message "puzzling for a move to ponder" on rare occasions.
>>>
>>
>>Hi Robert,
>>
>>how deep is Crafty searching in this short search. Depends this on the level?
>>I had the same idea with a search to ply 4, but not implemented yet.
>>
>>Andreas
>>
>
>I believe I use 10% of the "normal" target search time.  IE for a 3 minute
>(180 second) search, I "puzzle" for 18 seconds to get a move.  If you go
>too shallow you will get a bogus move to ponder on.  If you go too deep, it
>costs too much (in time) to get the ponder move.  10% seems to work pretty well
>for me...

thats of course better than a search to a fixed depth.

Andreas



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