Author: Robert Hyatt
Date: 06:49:37 02/04/04
Go up one level in this thread
On February 04, 2004 at 06:16:53, Mike S. wrote: >In the Crafty doc, I found: > >"9. computer This command usually comes from xboard/win- >board, but can be used at any time to tell Crafty it is >playing a computer. This will prevent some things from hap- >pening, such as a draw score that varies, as well as adjust- >ing the book selection code to be more selective in what it >plays." > >First I seemingly misunderstood that, thinking WinBoard would send that command >automatically when an engine match is run. This seems not to be the case >automatically, also not in Arena. (The engine responds to the command when I >include it in the Crafty.rc file, or typed it in when running Crafty in a DOS >box.) > >What exactly does this command change (I don't quite understand "draw score that >varies")? When playing humans, the draw score varies. It varies based on the rating difference between Crafty and the opponent. IE if Crafty is 2500 and the opponent is 2700 (server ratings) then crafty will prefer drawing. It doesn't at the moment, but in the past it has varied the draw score depending on the amount of time left on the clocks, so that if the opponent gets behind, it wants to draw even less. > >Does the search and evaluation remain the same (so that results from test suites >should be the same), with or without computer option? No. "computer" also disables some asymmetry in the evaluation that is more important when playing humans that want to "close" the position whenever possible. > >IOW., does it only affect book selection and gameplay behaviour so to speak? > >When the differences in book usage are not in effect (i.e. because GUI >controlled books or predefined opening variants are used): How is Crafty's >comp-comp performance affected, when the computer option is not turned on? Is an >estimation possible of the "long run" performance difference caused by that (if >any)? It will simply have an adjustable draw score with more asymmetry in the evaluation. > >I guess, many Crafty (offline) comp-comp games are played without switching that >option on - just because people don't know about it. I nearly never saw it was >mentioned anywhere in postings. > >Thanks, >Mike Scheidl I have not done this in a while, but I believe that xboard sends the "computer" command in matches, but I will check to be sure.
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