Mail Archives: djgpp/1998/05/07/06:48:17
Johan van Ooijen wrote:
>
> Hi,
> I am performing Monte Carlo simulation studies that require millions of
> runs. In order to predict how long each session is going to take I use
> trial sessions of 1000 runs. I find that it not possible to predict the
> duration of 10^6 runs. For instance, two sessions I predict to take 34
> and 68 hours, respectively (one should be exactly twice as long as the
> other), and they took 10 and 43 hours. It is fine that the sessions take
> shorter, but it is strange that the second is not even close to taking
> twice as long as the other. So this leaves me with the uncertain feeling
> of the correctness of the results, although they appear to be what I
> expect.
Just to be sure:
You do not have any power savings set in your BIOS or so,
so that your PC falls into suspend mode? I heard of
people running programs on a PC that fell into uspend mode
after 20 minutes of keyboard inactivity.
You are sure that run time should be linearily (sp?)
proportional to the number of loops?
Say, if you suppose
t= a*n + b
b is small enough to be neglected?
And, maybe the path the program takes inside the loop
might depend on a subtle way on the RNG. You might
try another one.
--
Ciao
Tom
*************************************************************
* Thomas Demmer *
* Lehrstuhl fuer Stroemungsmechanik *
* Ruhr-Uni-Bochum *
* Universitaetsstr. 150 *
* D-44780 Bochum *
* Tel: +49 234 700 6434 *
* Fax: +49 234 709 4162 *
* http://www.lstm.ruhr-uni-bochum.de/~demmer *
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