Author: José Antônio Fabiano Mendes
Date: 05:42:19 03/23/00
Go up one level in this thread
On March 23, 2000 at 07:33:13, Andrew Williams wrote: >On March 23, 2000 at 06:48:46, Francis Monkman wrote: > >>On March 23, 2000 at 06:14:22, Andrew Williams wrote: >> >>>On March 23, 2000 at 05:16:56, Francis Monkman wrote: >>> >>>>On March 23, 2000 at 03:09:33, Jason Williamson wrote: >>>> >>>>>I have been running Amnon 5.06 under Fritz and have noticed really WEIRD >>>>>pondering by Amnon. It almost seems that it was just randomly looking at a move >>>>>and analysing it, even if said move just dropped a queen in one move, or a piece >>>>>or what ever. Mind you, it plays ok on its own time, and still maintains a >>>>>position of one of the top 5 or 6 amatuer chess engines I have. >>>>> >>>>>Jason >>>> >>>>If I'm not mistaken, this problem is related to the difficulty of extracting a >>>>pv line from an MTD(f) search. >>>> >>>>Francis >>> >>>This is interesting (to me anyway). My program uses mtd(f) and it extracts >>>its PV from the hash table. I found that if the hash table is of a reasonable >>>size, the PV for the first several plies is usually OK. >>> >> >>It was just the other day (after some experiments with MTD(f), storing pv in >>hash table etc) that I noticed that AnMon's pv line in Winboard was clearly >>printing garbage. I note your use of the words 'reasonable' and 'usually' with >>interest! >> > >OK. "Reasonable" of course depends on the length of the game to some extent. >PostModernist usually uses 256K entries in its main hash table. Sometimes it >runs with 512K entries. I only have 64MB RAM on both the machines I use, so my >hashtables aren't huge compared to some others. As for "usually", I present >these figures with some trepidation: A long time ago I was worried about this >issue and I tried to calculate how frequently the score generated by a search >corresponds with the score I get if I walk down the PV and evaluate the position >at the end. I found that in >90% (I think) of cases with test positions, I got >a match. The figure for playing games (against gnuchess I think) was either 59% >or 64%, I can't remember which. At the risk of being misunderstood, I think the >early part of my PV is "usually" OK. :-) > >>BTW on this topic, I wrote to Prof Hyatt recently pointing out that I'd found >>identicalities in the 17 lsbs (all I'm using for hash address-generation in a >>Chess variant, Shatra) of the piece hashkeys' random numbers output by the >>'Knuth' algorithm he implements in Crafty. Also that Knuth now (1990s revision) >>proposes a fix for said algorithm. > >I use the "Mersenne-Twister" random number generator, because it sounds really >cool. > >Andrew Mersenne Twister Home Page http://www.math.keio.ac.jp/~matumoto/emt.html JAFM
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.