Author: William Penn
Date: 09:49:53 02/03/04
Go up one level in this thread
On February 03, 2004 at 11:02:05, Bob Durrett wrote: >On February 03, 2004 at 08:09:52, William Penn wrote: > >>On February 03, 2004 at 04:32:35, Matthias Gemuh wrote: >> >>> >>> >>>Zied Haddad seems to be unable to connect to CCC from Tunesia. >>>He seeks to know whether others have encountered a Shredder 8 problem he has: >>> >>>after playing many games in a row without clearing hash tables, Shredder 8 >>>starts messing and missing even mate in 1, till hash tables are cleared. >>> >>>[http://f50.parsimony.net/forum200321/messages/5855.htm] >>> >>>/Matthias >>>(message posted on Zied's request) >> >>You may be right. I'm not sure yet, but I will start clearing the hash tables >>before each analysis and see if it makes a difference. Note that I only run >>Shredder 8 in infinite analysis mode for a long time to analyze positions. > ><snip> >> >>WP > >(1) I read somewhere that it's always a good idea to clear the hashtables >before starting a new analysis but do not recall the reason. Nevertheless, I >now always hit that "clear hashtable" button whenever I see it. > >(2) The PV for Shredder is total garbage except for the first move and this is >a known bug in Shredder, acknowledged by it's author. It hopefully will be >fixed one of these days. The sooner the better. > >(3) With some engines, I notice another bug which may or may not be related to >this one. While doing user-guided infinite analysis, sometimes the nps number >drops to a tenth of it's normal value. When that happens I cuss a little and >then save the position, turn off the engine, and then restart it, clearing the >hashtable. Then the nps goes back to a reasonable value. I do not recall which >engine does this, but it has to be either Crafty, Shredder, Fritz, Hiarcs, >Tiger, or Junior since those are the engines I use as CB8 analysis engines and >for overnight automated game analyses. > >(4) I still have not learned how to use Chessmaster for analysis, perhaps >because I'm getting overly senile. It's a pity that The King is not available >as a CB8 analysis engine because if it were I would use it often. > >Bob D. Thanks for the info. Can you tell me what "PV" means? I see it mentioned all the time but have never run across the definition. As for nps dropping drastically to 1/10th of it's normal value... That can happen in endgames with any engine due to heavy tablebase access, although it's not usually so drastic. You can tell if that's the case because of constant hard drive access (the hard drive activity light stays on). I've also seen some significant dropping of nps with the Shredder 8 Gambit engine, but again not so drastic, perhaps to 1/3rd of normal value. I haven't seen that happen with the native Shredder 8 engine, which is usually fairly constant speed in a particular position. There's also the possibility for the counter in some older engines to wrap back around to zero when it gets to a certain value, a large number which I don't recall offhand. That causes a big drop in nps, but it's only artifical - the speed hasn't actually slowed down. WP
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.