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Subject: Re: PONDER=ON and TableBases on 1 PC

Author: Robert Hyatt

Date: 07:59:33 07/28/01

Go up one level in this thread


On July 28, 2001 at 04:17:18, Uri Blass wrote:

>On July 28, 2001 at 01:12:41, Terry McCracken wrote:
>
>>On July 27, 2001 at 18:58:30, Dann Corbit wrote:
>>
>>>On July 27, 2001 at 18:44:45, Roy Eassa wrote:
>>>
>>>>On July 27, 2001 at 16:55:55, Dann Corbit wrote:
>>>>
>>>>>On July 27, 2001 at 16:51:08, Roy Eassa wrote:
>>>>>
>>>>>>Be careful, Dann.  Dr. Hyatt has argued strongly that ponder should always be
>>>>>>on, even with a single CPU.  (It seemed counter-intuitive to me too, but you
>>>>>>should check out his recent postings -- over the past couple days, I think.)
>>>>>
>>>>>Not when both engines play on the same machine.
>>
>>
>>>>>No way.
>>>>
>>>>
>>>>Yes way!  I reacted the same way (in my head), but I respect Dr. Hyatt and his
>>>>arguments are worth reading at least!
>>>
>>>If you run two engines which are both pondering on a single CPU machine, then
>>>you are simply out of your mind.
>>>
>>>I think you must have misread the arguments.
>>
>>No Dan he's read the arguements correctly!
>>
>>Posted by Robert Hyatt (Profile) on July 27, 2001 at 13:28:16:
>>
>>In Reply to: Re: Permanent Brain ON vs Permanent Brain OFF posted by Uri Blass
>>on July 27, 2001 at 11:58:57:
>>
>>
>>On July 27, 2001 at 11:58:57, Uri Blass wrote:
>>
>>>On July 27, 2001 at 11:18:08, Miguel A. Ballicora wrote:
>>>
>>>>On July 26, 2001 at 14:41:54, Robert Hyatt wrote:
>>>>
>>>>>On July 26, 2001 at 12:55:06, Miguel A. Ballicora wrote:
>>>>>
>>>>>>On July 26, 2001 at 10:43:45, Robert Hyatt wrote:
>>>>>>
>>>>>>>On July 26, 2001 at 09:56:24, Matthias Gemuh wrote:
>>>>>>>
>>>>>>>>
>>>>>>>>Hi Robert,
>>>>>>>>
>>>>>>>>I think you just wanted to make a joke. We all know that PONDER OFF hurts nobody
>>>>>>>>(Fritz used its full time). PONDER ON on one CPU is very appropriate to arrive
>>>>>>>>at wrong engine comparasons.
>>>>>>>>
>>>>>>>>Regards,
>>>>>>>>Matthias.
>>>>>>>
>>>>>>>
>>>>>>>>>>>>both will get 1/2 of the machine and the time controls won't be screwed up.
>>>>>>>
>>>>>>>ponder=off exposes the opportunity for a program to get into time trouble
>>>>>>>because it assumes it will save time with ponder=on when it really can't since
>>>>>>>it is disabled...
>>>>>>
>>>>>>Why the program should assume that it will save time in with ponder=on when
>>>>>>it knows that it is off already?
>>>>>>Shouldn't a program take this into account?
>>>>>>If ponder=off is an option for the program, it should notice the difference
>>>>>>and act accordingly IMHO.
>>>>>>
>>>>>>Regards,
>>>>>
>>>>>
>>>>>because in my case, 99.9% of all games played have ponder=on.  I only disable
>>>>>pondering to debug so that I can reproduce the same searches over and over
>>>>>when necessary.  Since almost all real games are played with ponder=on, I don't
>>>>>have a special time-allocation formula for ponder=on and another one for
>>>>>ponder=off.  I just have one that _assumes_ ponder=on.
>>>>>
>>>>>I see no reason to waste what little time I have working on something that is
>>>>>hardly going to be used...
>>>>
>>>>Well, it is used a lot actually by lots of people already. Most of the people
>>>>are running matches with ponder=off for some reasons.
>>>>If both engines were tuned for ponder=off, it will be the best condition to
>>>>optimze the resources since time used pondering is never as good a time used
>>>>thinking. For instance, you have a competitive mindset in your answer but if my
>>>>purpose is to run a match between engines to learn a particulat opening, I want
>>>>my resources to be used as efficient as possible. That is ponder=off for both.
>>>>Maybe you could consider making Crafty to be able to process "ponder=off"
>>>>accordingly because there will be users that would benefit from it.
>>>>
>>>>Regards,
>>>>Miguel
>>>
>>>Crafty is not a commercial program so I guess that the way that users use it is
>>>not important for Bob.
>>>
>>>I also do not think that the difference between ponder on and ponder off is more
>>>than 20 elo in most of the practical cases.
>>>
>>>Uri
>>
>>
>>I disagree.   When this first cropped up a couple of years ago, I ran a test,
>>gnuchess on a single-cpu, vs crafty on a quad pentium-pro 200, but using only
>>one cpu.  The quad was far slower than the 500mhz single cpu by a significant
>>amount.  The match was pretty even (ponder=on) even though crafty had a much
>>slower processor.  With ponder=off, the match was way more lop-sided in favor
>>of GNU because crafty would get into time trouble and near the end of the
>>time period it would have to move too quickly to avoid losing on time.
>>
>>It was _clearly_ worse.  And by more like 100 points, too.  I adjusted it a bit
>>to help, but I have _never_ invested as much time in the ponder=off timing as
>>I have in the ponder=on timing.  And I never will, any more than I am going to
>>try to tune my son's mustang to run on a road coarse when we only take it to
>>the 1/8th and 1/4th mile drag strips...
>>
>>I think you should spend the time making it optimal in the way it will normally
>>be used, not in oddball configurations...
>>
>>
>>I ran a bunch of games, everything equal but the hardwar
>>
>>
>>Quote/Hyatt; Nope... no joke at all.  Two programs, one machine, my preference
>>is ponder=on.
>
>Note that it is hyatt's opinion.
>I said that in most of the practical cases the difference between ponder on and
>ponder off is not more than 20 elo.
>
>The practical cases are usually with the commercial programs.
>I am not talking about amatuers like GNUchess.
>
>I agree that there may be a big difference with amatuers.
>One reason is simply the fact that part of the amatuers do not know to ponder so
>ponder off is clearly better for them than ponder on.
>
>I do not know if this was the reason for GNU chess but when I read 100 elo
>difference I suspect that this is the reason.
>
>I do not believe that program are handicapped by more than 100 elo if they do
>not know to ponder.
>
>I believe that the difference is even less than 70 elo(70 elo is the difference
>from doubling the speed of the program and it is better to be twice faster and
>play without pondering).
>
>Uri


No...  the problem was definitely in crafty.  I was playing games of 15 minutes
for 40 moves.  At move 35-40, crafty was in time trouble and made bad moves in
many (but not all) games because it had far less time than GNU did.  You can't
afford to do a 6-8 ply search and move when your opponent is doing 10-12 plies
on that same move because he has used his time more reasonably.

I fixed the problem in a simplistic way by simply spreading out the time over
the time-control-moves in a more uniform way.  Very unlike the way a human plays
chess of course, but it was one quick-and-dirty way to avoid getting blasted
near the end of the time control.



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