Author: Gerd Isenberg
Date: 14:05:18 04/06/04
Go up one level in this thread
On April 06, 2004 at 14:56:39, Robert Hyatt wrote: >On April 05, 2004 at 16:29:00, Gerd Isenberg wrote: > >>On April 05, 2004 at 15:51:43, Robert Hyatt wrote: >> >>>On April 05, 2004 at 15:02:56, Gerd Isenberg wrote: >>> >>>>On April 05, 2004 at 14:11:34, Robert Hyatt wrote: >>>> >>>>>On April 05, 2004 at 12:27:50, rasjid chan wrote: >>>>> >>>>>>On April 05, 2004 at 11:05:30, Robert Hyatt wrote: >>>>>> >>>>>>Thanks, but I don't need to test yet as you have tested ! >>>>>> >>>>>>I think using nodes searched should be good. >>>>>>If a move fails low with very few nodes searched, it probably >>>>>>mean being rejected easily, so sort low. >>>>>> >>>>>>Rasjid >>>>> >>>>>Correct most of the time. Sometimes a move will have a high node count just >>>>>because there are lots of checks and extensions. But I've been sorting by node >>>>>counts for 15+ years with good results, of course forcing the PV move to always >>>>>be at the top regardless of its node count... >>>>> >>>> >>>>I use node count per root move too. >>>>What about following "enhancement": >>>>If PV changes, to store (some) "previous" PV moves and to use them early after >>>>current PV move, regardless of their node counts? >>> >>> >>>It is worth testing. It didn't work for me in crafty or Cray Blitz, but it >>>might work for another program. I always had the best luck overall by just >>>using pure node counts... >>> >>>It helps the most when there is a "best" move that you won't find until deeper >>>depths. It will percolate up the list, iteration by iteration, so that it is >>>near the top on the iteration where it becomes best. I also use this >>>information in my parallel split/dont-split at the root adaptive algorithm in >>>Crafty... >> >> >>Yes, exactly my experience. Anyway i occasionally noticed a former PV move had >>low node count (e.g. a forced draw line) but a new PV move suddenly fails below >>draw score. Im such cases trying the "safe" drawline earlier may help to waste >>some time. > >Those are the cases that blow my adaptive "split/don't-split at the root" SMP >code. A repetition will produce a very small tree. If this is best, then most >of the remaining root moves might produce larger node counts, which makes it >look like they are all potential new best moves. I catch this, but not very >well... Another point i had problems with was during games, less node count due to (exact) hash hits from the previous search two plies before. Then finding something better which fails low next iteration - and the best move was searched at the end ;-(
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