Author: Uri Blass
Date: 03:39:16 01/20/04
Go up one level in this thread
On January 20, 2004 at 00:12:03, John Paul Jones wrote: >On January 19, 2004 at 23:23:58, Robert Hyatt wrote: > >>On January 19, 2004 at 19:52:36, John Paul Jones wrote: >> >>>On January 18, 2004 at 22:39:23, Robert Hyatt wrote: >>> >>>>On January 18, 2004 at 05:53:49, martin fierz wrote: >>>> >>>>>i just received my brand-new shredder 8. when using it for analysis in chessbase >>>>>(which is in fact the only thing i use it for), it often gives PVs which are >>>>>completely ridiculous - the first few moves are ok, then one side blunders a >>>>>piece according to the PV, but the evaluation of that line doesn't show it. >>>>>looks like there is a PV bug in shredder 8? is there any fix for this? i find it >>>>>very annoying... >>>>> >>>>>cheers >>>>> martin >>>> >>>> >>>>I have heard that Shredder (and others) try to reconstruct the PV by probing the >>>>hash table at the end of the search. This simply does not work with any degree >>>>of accuracy. IE suppose you search and reach position A while searching the PV. >>>> Later, at very shallow depths, you reach position A again and >>>>overwrite it with different "best moves" depending on the depth remaining, >>>>extensions triggered, etc. Now when you try to recover the PV from the hash >>>>table, you get the right position A, but the wrong best move. And then the PV >>>>looks funny. It doesn't happen every time, but if the PV is reconstructed >>>>enough this way, it happens often enough. I tried this _years_ ago and ran into >>>>the same problem. Never saw it in debugging. Saw it regularly when kibitzing >>>>PVs on ICC. :) >>>> >>>>I now do it the correct way, backing the PV up along with the score... >>>> >>>>Remember that this is speculation since I have never seen Shredder's source. But >>>>recovering the PV in this way is simply going to produce errors, and there is >>>>nothing that can be done about it. The first move and score will be correct, of >>>>course. But beyond that, who knows, and the farther out, the greater the >>>>probability of a bogus move. >>> >>> >>> >>> It's halarious how you try to tell more sucessfull programmers what will and >>>what will not work, and your program is like 200 elo points behind theirs... >>>funny indeed! >> >>It's hilarious to watch you try to talk about computer chess with _no_ idea >>of what you are talking about. :) >> >>Hint. There is a difference between algorithms, and implementations of >>algorithms. Here nobody disputes that PV from hash shows bogus PVs. >> >>Please show another touch of brilliancy now... > > >haha well atleast I admitt that I know nothing about computer chess, and don't >go around acting like I'm a brilliant programmer when I have a Second rate >program that nobody respects. Speak for yourself. Do not speak for everybody. Nobody respects is simply wrong. Uri
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.