Author: Alex Boby
Date: 21:34:37 06/22/99
Go up one level in this thread
On June 22, 1999 at 19:04:11, Andrew Williams wrote:
>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?
>>
>>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
>
>
>Just a couple of points to follow up my previous response:
>
>1. As far as I can see, clock() is used to get information about *processor*
>time, not elapsed time. So it wouldn't be strange if your program used
>10 seconds of processor time in 25 seconds of elapsed time. Again I get this
>information from the man pages, which may be out of date.
>
>2. The man page for gettimeofday (see my other response) says something about
>the timezone struct being obsolete. I don't understand this, but if anyone
>knows more about this I'd be very grateful to know.
>
>Cheers
>
>Andrew Williams
I've already implemented your idea and it fixed the problem completely,
thank you. I also read the man pages about that obsolete timezone struct. They
say that the timezone struct contains an indicator for daylight savings time,
but there's no way an algorithm could use this information (to know which dates
DST are in effect for) because those dates are chosen for political reasons in
many countries and not based on geographical location or anything like that. So
the structure was abandonned because it's useless. This is how I understood it.
Alex Boby
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