about a bug of movei and losing on time

[Uri Blass]

Geschrieben von:/Posted by: Uri Blass at 13 April 2004 02:04:36:

I discovered a bug in movei that can cause it rarely to lose on time when it ponders(based on my experienece less than 1 out of 100 games when the bug is not dependent on time control)
Example of the bug:
Movei had 42.35 seconds for moves 115-120
Movei used 21.40 seconds to calculate move 115(it is slightly more than half of the time but movei does not check if more than half of the time passed in every node)
part of the 21.40 seconds were during pondering so Movei practically has 22.04
seconds for moves 116-120.
Movei starts to ponder.
during pondering movei gets winboard command that tells it that the
remaining time is 22.04 seconds.
This command update the varaible max_time but it does not update
the varaible stop_time so movei still "believes" that it can use at most half
of the original 42.35 seconds in case that it needs to stop at the middle of the iteration but it is using max_time to decide if to stop at the end of the iteration.
Unfortuantely movei again is unlucky to stop at the middle of the iteration(it does not happen very often and this is the reason that the bug is rare).
This time movei used 21.18 seconds for move 36 when only small part was during pondering so movei is in big time trouble and later it is going to lose on time
at move 120.
I plan to replace every stop_time by start_time+max_time so I can get rid of a varaible and a bug.
Uri