Author: Robert Hyatt
Date: 07:19:16 02/01/99
Go up one level in this thread
On February 01, 1999 at 03:50:59, Bruce Moreland wrote: > >On February 01, 1999 at 00:51:40, Don Dailey wrote: > >>We had an assertion failure during one tournament I am embarassed to admit. >>I am embarassed for two reasons, the debugging should have been turned >>off, and the program should not have failed. It was one of those >>castling bug things. The assertion picked up the error fortunately, >>it would have been tough finding this one without the assertion. >>It was a very beautiful bug though. Every assumption and test about >>castling failed due to a rare set of circumstances that had to happen all >>together in order to produce the bug. It was beautiful like a composed >>chess problem. The program was restarted and fortunately the bug did >>not occur again and I fixed it after the game was over. But if the >>bug had continued to occur, we would have lost the game unless the >>tournament director had allowed a recompile and I doubt he would have. > >I once asked a group of chess programmers how many of them would mess up in the >following situation, and I got one or two sheepish "me" responses. > >White has rooks on h1, a1, king on e1, can castle either way, black has bishop >on h8, king on e8, black to move. > >Black plays Bxa1, and while black fiddles with his king, white plays Rh2, Ra2, >Rxa1 and O-O-O. > >The reason this might cause problems is that the a1 rook never moved. > >bruce I at least catch that one... Bxa1 clears the queen-side castling flag just as though the a1 rook had moved...
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.