Author: Robert Hyatt
Date: 19:14:08 06/22/99
Go up one level in this thread
On June 22, 1999 at 15:18:17, Alex Boby wrote: > >A couple problems with timing... > >1. In my limited spare time I've just done the switch over from depth based to >time based searching. I am now having difficulties coming up with an algorithm >to choose the amount of time which should be spent searching for each move. This >is a trivial task if the time controls are x moves in y minutes but if the time >controls are simply x minutes for the whole game (like on ICS), then what's the >most efficient way to use the time? use target=time_left/X, where X is a constant of your choice. 25-30 work pretty good, which gives a steadily decreasing time per move as time is burned away... But experiment with X until _you_ are happy with the usage pattern... > >2. I am developing in C under linux and using the clock() command for all >timings. The problem I have is that when it says that it took, for example, 10 >seconds to search, it's in actuality more like 25 seconds. At first I thought >that I had some kind of problem with casting or arithmetic but I checked all >that. I also examined crafty's code and it seems exactly the same as far as >usage of clock() is concerned. Then I thought that maybe my clock chip was >malfunctioning, but if this were the case then my system would not be keeping >accurate time,... but it is. Therefore I have no idea what the problem could be, >but it's a pretty significant one as far as I'm concerned. Any ideas? > >Much thanks, >Alex Boby There are _two_ times under unix. clock() returns the total cpu time used. gettimeofday() is used to return wall-clock time, which is more important in chess. In general, cpu and wall-clock times should step along together unless your machine is doing more than one computational task... or unless your program is doing a lot of I/O for some reason...
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.