Author: Omid David Tabibi
Date: 14:15:52 07/14/04
Go up one level in this thread
On July 14, 2004 at 17:10:13, Matthew Hull wrote: >On July 14, 2004 at 17:03:33, Omid David Tabibi wrote: > >>On July 14, 2004 at 17:00:04, Matthew Hull wrote: >> >>>On July 14, 2004 at 16:53:39, Omid David Tabibi wrote: >>> >>>>On July 14, 2004 at 16:44:00, Peter Berger wrote: >>>> >>>>>On July 14, 2004 at 12:56:10, Omid David Tabibi wrote: >>>>> >>>>>>On July 14, 2004 at 12:34:18, Peter Berger wrote: >>>>>> >>>>>>>On July 14, 2004 at 12:28:29, Omid David Tabibi wrote: >>>>>>> >>>>>>>>On July 14, 2004 at 12:19:24, Peter Berger wrote: >>>>>>>> >>>>>>>>>On July 14, 2004 at 11:41:04, Omid David Tabibi wrote: >>>>>>>>> >>>>>>>>>>On July 14, 2004 at 11:38:31, Peter Berger wrote: >>>>>>>>>> >>>>>>>>>>>On July 14, 2004 at 11:26:47, Omid David Tabibi wrote: >>>>>>>>>>> >>>>>>>>>>>>On July 14, 2004 at 11:12:14, Fernando Villegas wrote: >>>>>>>>>>>> >>>>>>>>>>>>>Not at all, Omid >>>>>>>>>>>>>If you already have a parallel engine you should run it into a >>>hardware capable >>>>>>>>>>of getting all its power. >>>>>>>>>>>> >>>>>>>>>>>>I understand that you are going to provide the hardware, right? >>>>>>>>>>>> >>>>>>>>>>>>It is not something personal; next year I will have the needed >>>hardware, but >>>>>>>>>what about others? Deep Sjeng and ParSOS were also >>>parallel engines, but ran on >>>>>>>>>single processor not because they >thought >>it was better, but because they did >>>>>>>>>not have access to a >fast >>multiprocessor machine. >>>>>>>>> >>>>>>>>>>> >>>>>>>>>>>I wonder what except the results changed from two weeks ago to now to >>>make you >>>>>>>>imply this is an unfair event and go on raving about it ?! >>>>>>>>>>> >>>>>>>>>>>Weren't you even one of the organizers? >>>>>>>>>> >>>>>>>>>>Yes, and I complained loudly about it even before the event. >>>>>>>>> >>>>>>>>>Actually I still think this is argueing with hindsight. Diep and Crafty >>>finished >>>>>>3rd and 4th, a result that surprised some of the present >>>programmers. >>>>>> >>>>>>>>>It seemed to concern no one last year when it was only the >professionals >>who >>>>>>came with superior hardware. >>>>>>>>> >>>>>>>>>To quote another programmer from memory: "I typically get 80% in tests >>>against >>>>>>Crafty, so on a Quad it might get 30% or sth like that ". >>>>>>>>> >>>>>>>>>And we don't know how the results would have looked like in a single >CPU >>event >>>>>>either - before the tournament it was "Crafty is a miserable >>>program that I can >>>>>>beat on any hardware" (simplified and no quote) - >>>>>>>> >>>>>>>>This quote is not from me. >>>>>>> >>>>>>>And I didn't imply any different. >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>>>at least one part of this >>>>>>>>>statement turned out to be untrue. >>>>>>>>> >>>>>>>>>Maybe the hardware impact is a little overrated in this discussion >>>anyway. Jonny >>>>>>on a PIV2.8 e.g. nearly finished Junior on a Quad. >>>>>>>> >>>>>>>>You want to measure the hardware impact, just do the following: >>>>>>>> >>>>>>>>Run the Crafty benchmark at a fast single processor machine, and also on >>>the >>>>>quad machine: >>>>>>>> >>>>>>>>ratio = (benchmark on quad) / (benchmark on single proc) >>>>>>>> >>>>>>>>(the ratio would be about 4) >>>>>>>> >>>>>>>>Next, for each move of Crafty in the tournament, divide the thinking >time >>by the >>>>>'ratio' above, to get a new time: >>>>>>>> >>>>>>>>time2 = (original time spent on the move) / ratio >>>>>>>> >>>>>>>>Now just count how many times Crafty changed its PV after 'time2'... (In >>>other >>>>>words, how many times Crafty changed its PV after thinking for 1/4 >>>of the time >>>>>on the move.) >>>>>>> >>>>>>>This test sounds more scientific and logical than it is. You also would >>>have to >>>>identify the moves that would make any difference to the result >of >>the game. >>>> >>>>>>>I can easily reproduce all critical moves of the Falcon-Crafty game on my >>>>>>>notebook for black. I already asked you in another message if more time >>>would >>>>have made any difference for Falcon for two of its critical >mistakes >>- you >>>>didn't answer yet. >>>>>> >>>>>>Just count the number of times Crafty changed the PV after 1/4 of its >>>thinking >>>time (including pondering), and see how many of them were >critical, >>and >>>prevented a loss. >>>>>> >>>>>>You will find many of them. Here is one I remember clearly: After Falcon's >>>>>>...Ra5 in the endgame, Crafty wanted to repeat the position at first >(score: >>>>>0.00). It thought for a long time, and then changed the PV to >other move, >>which >>>was winning. But you will find many other moves in the >earlier stage >>of the >>>game, which would have resulted in a loss were they >played (after >>thinking for >>>1/4 of the time). >>>>> >>>>>I think you maybe misunderstood me here because of the heat of the >>>discussion. >>That I can easily reproduce Crafty's moves on my notebook >doesn't >>mean that all >>its moves were found fast and easily :). >>>>> >>>>>From memory there were two moves in the tournament where Crafty changed its >>>mind >>very late and that turned out to be of big importance. >>>>> >>>>>Kb6 (or whatever the move after Falcon's Ra5, no surprise that we both >>>remember >>this one) >>>> >>>>OK, so at least you agree that without the 4x hardware advantage Crafty >>>wouldn't >have got more than a draw. >>>> >>>> >>>>> and g5 in the game against Diep. >>>>> >>>>>In case there were other moves like that, I am at least not aware of it. >>>>> >>>>>I expect Bob to offer Crafty's logfiles for download soon as he did for >>>cct-6, >>so maybe we should delay this discussion until we can just discuss >the >>real data >>( I don't have access to the Opteron anymore). >>>>> >>>>>I would still be interested to know about the critical points from >Falcon's >>>>side; Ra5 is a trial to avoid repetition - you have to search very >deep to >>>>dismiss it. >>>> >>>>One iteration deeper Falcon switches to the other move which results in >actual >>>threefold repetition. >>>> >>>>In other words, had Crafty not had the hardware advantage it would have >missed >>>the win, and had Falcon had the 4x hardware it would have found the >correct >>draw >(and with that hardware advantage probably also found a correct >winning >>line). >Right? >>> >>> >>> >>>Why don't you just test it. Download crafty19.15 and setup the appropriate >>>time controls for each side and start from some move in the actual game. >>> >>> >>>Then we won't be in fantasy land anymore, but in the land of fact. >> >>It is not fantasy. During the actual game Crafty found the correct move in the >>endgame after a very long search (previous best move was threefold >repetition). >Peter was the operator, and has said the same in the post above. >Quoting him: > >>"From memory there were two moves in the tournament where Crafty changed its >>mind very late and that turned out to be of big importance. Kb6 (or whatever >the >move after Falcon's Ra5, no surprise that we both remember this one)" > > >No, I meant that Falcon could find _winning_ lines, not just drawing lines. I will try the game to see if there was a clear winning line. But it is clear that on equal hardware white would not have lost the game. >Remember that Boris said many times that the game was over in favor of white. >So white should have won. Give Falcon equal time as crafty, and long time to >simulate 4x opterons. > >Then we should know if you would really have won that game with equal hardware. > > >The other experiment is to substitute Junior for Falcon on the slow hardware >setup and see if Junior also cannot win on uniprocessor. > >> >> >>> >>> >>>:) >>> >>> >>> >>>> >>>> >>>> >>>>>And Ra8 is probably not about search at all. >>>>> >>>>>Peter
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.