Author: Uri Blass
Date: 09:22:30 10/08/02
Go up one level in this thread
On October 08, 2002 at 12:10:41, Robert Hyatt wrote: >On October 08, 2002 at 10:55:29, Uri Blass wrote: > >>On October 08, 2002 at 10:50:20, Robert Hyatt wrote: >> >>>On October 08, 2002 at 07:08:51, Uri Blass wrote: >>> >>>>On October 08, 2002 at 00:52:38, Eugene Nalimov wrote: >>>> >>>>>Wrong. >>>>> >>>>>Today I visited the talk by Feng-Hsiung Hsu he gave at Microsoft. Here are some >>>>>points from memory: >>>>> >>>>>They used forward pruning in the hardware, and according to Hsu it gives them >>>>>5x-10x speedup. He wrote about that in the book, too, but without any details. >>>> >>>> >>>>Can you ask him if 12(6) really means 12 plies in the software and 6 plies in >>>>the hardware? >>>> >>>>A second question is if the plies in the hardware were selective search from the >>>>first ply. >>>> >>>>>In the talk he named that pruning as "analogy cutoff" and mentioned that "if the >>>>>move is useless in some position, it is also useless in the similar position". >>>>>In the book he writes "it can be done in the hardware as long as it does not >>>>>have to be 100% correct". >>>>> >>>>>They used null-move thread detection, as well as not only singular extension, >>>>>but also extension on only 2 or 3 good replies. They used fractional extensions. >>>>>He also says that their Q-search is much more powerful than the one that is >>>>>usually used in the software-only programs. >>>>> >>>>>Hsu gave some details why they don't use null-move: >>>>>(1) He thinks that singular extensions and null-move gave more-or-less the same >>>>>rating difference (100-200 points IIRC). >>>> >>>>I think that he underestimates null-move pruning. >>>> >>>>I believe that for long time control null move pruning gives more than 100-200 >>>>points. >>>> >>>>People may try Fritz with selectivity=0 to find it's rating without null move. >>>> >>>>Uri >>> >>> >>>I can assure you it doesn't. Several of us ran this experiment in the past. It >>>produced a 50-100 >>>point improvement at most. Bruce ran it first. I then repeated it to see if >>>his result held for me >>>as well. 50-100 is nothing to sneeze at of course... But that is all it will >>>give... >> >>What was the time control and the hardware. >> >>I believe that the improvement is bigger >>at slower time control. >> >>If the experiment was some years ago and >>in time control that is faster than 120/40 >>then the results may be different today. >> >>Uri > > >I don't know about Bruce. I used 40 moves in one hour followed by 20 moves in >30 minutes, >with no sudden-death at all. > >I ran it on several computers here for several weeks... We have a factor of 2 in the time control. What was the hardware that was used? If the games were played 5 years ago then today we have clearly faster hardware. Uri
This page took 0.01 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.