Author: Uri Blass
Date: 11:25:58 05/06/01
Go up one level in this thread
On May 06, 2001 at 14:16:04, Paul wrote: >On May 06, 2001 at 14:01:22, Terry McCracken wrote: > >>On May 06, 2001 at 05:40:02, Uri Blass wrote: >> >>>On May 06, 2001 at 03:51:47, Paul wrote: >>> >>>>On May 06, 2001 at 02:28:14, Uri Blass wrote: >>>> >>>>>I gave Deep Fritz to analyze similiar number of nodes to Deeper blue and Deep >>>>>Fritz seems to be clearly better in tactics. >>>>> >>>>>Deep Fritz needs only 191728 knodes to see the line Rf5+ Ke3 >>>>>It means only 1 second if I asuume 200,000,000 nodes per second. >>>>> >>>>>I believe that Rf5+ failed low at depth 17 for Deeper blue for the reason Ke3. >>>>>The pv of deeper blue at smaller depthes is Rf5+ Ke2 >>>>> >>>>>Deep Fritz probably does better extensions than Deeper blue because Deep Fritz >>>>>see big fail low at depth 16. >>>>> >>>>>Deep fritz also can see another fail low for Rg8 at depth 22 when deeper blue >>>>>could get only depth 17 after similiar number of nodes. >>>>> >>>>>I do not believe that you lose more than 2-3 plies from null move pruning(my >>>>>test suggest that you do not lose even 1 ply at small depthes so I guess that >>>>>Deep Fritz can search deeper because it is a better software. >>>>> >>>>> >>>>>kasparov - Deeper blue >>>>>4r3/8/2p2PPk/1p1r4/pP2p1R1/P1B5/2P2K2/8 b - - 0 1 >>>>> >>>>>Analysis by Deep Fritz: >>>> >>>><snip> >>>> >>>>I remember from the time this match was played that this was due to some bug >>>>which was subsequently corrected, so there's not much sense in discussing this >>>>position. Any other will do, but not this one. Even my program finds Rf5+ in >>>>seconds. >>>> >>>>Groetjes, >>>>Paul >>> >>>I know about the bug >>> >>>I am not talking about finding Rf5 but about finding the reason that Rf5+ is >>>losing. >>> >>>I mean to find the fact that line Rf5+ Ke3 that is good for white. >>>Deeper blue could not see it at iteration 16 and the logfile suggests Rf5+ Ke2 >>> >>>Deeper blue had a fail low at iteration 17 and the logfile does not give a line >>>for Rf5. >>>I guess that it failed low because of Ke3. >>> >>>The point is that Deeper blue is slower than top programs in failing low. >>> >>>Deeper blue could not find Rf5+ Ke3 after 73 seconds when Deep Fritz can find it >>>in a few minutes on p800 and it means that it could find it in less than second >>>if it could search 200M nps. >>> >>>Uri >> >>I think you're right Uri if you dragged out Deep Blue of May 1997 or at least >>close. >>But you have to remember it was 1997 and if my memory serves me correctly, >>Kasparov was very puzzled by Rf5+ as programms just didn't look at this move >>at that time, except for Deep Blue in such a short time frame. >>At least that's what I remeber from what Kasparov mentioned in his notes. Not >>the exact words, I'm not quoting what Kasparov said or wrote but just what I >>remember from that time, on the "Old Club Kasparov" hosted by IBM which is long >>gone. >>I also remember after many hours of analysis with "computers of the day" >>P6-200's, that Kasparov finally "understood" why Deep Blue played the "Human" >>looking move, Rf5+. >>Actually, I think Kasparov wasted too much energy trying to understand Deeper >>Blue which I believe exhausted him. Hence, his less than stellar preformance >>in Game 2 and the rest of the match. >> >>Terry McCracken > >Deep Blue didn't play Rf5, it played Rd1! Uri wants to analyze the evaluation >out of the log of Deep Blue ignoring the bug. Seems impossible to me. :) > >Paul I believe that the bug happened only after failing low on Rf5. The logfiles do not give a score for Rd1 so I believe that the bug is not relevant for Rd1 The last line of the logfile of game 1 begins with 11(6)[Rf5](-260)v [find a move] I never see the words find a move in deeper blue in other cases and it suggests that the bug happened only after Deeper blue failed low. The line for Rd1 is also a short line when previous lines are long lines so I trust the analysis of deeper blue at depth<17. Uri
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