Re: srand in a tclforces script

From: Vlad Cojocaru (
Date: Thu Dec 11 2008 - 08:31:37 CST

Dear all,

Sorry .. mea culpa ... I had a wrong syntax for "srand" in my tcl script
and that's why namd was complaining ...
Now it works .. I get identical results in identical conditions ..


Vlad Cojocaru wrote:
> Dear NAMD users,
> I have a tclforces script in which I need to intialize a random unit
> vector. I use the tcl "rand" function twice for that purpose (to
> generate the spherical coordinates theta and psi).
> However, If I run a simulation twice using the same "seed" parameter
> in the NAMD configuration file I still get different results between
> the 2 simulations.
> So, I thought to initialize the random number seed before the first
> "rand" call in my tcl script using the tcl "srand" function. However,
> NAMD complaints and I get an error saying that it is not possible to
> set srand in the tclforces script.
> Does anyone have any idea what could I do to have exactly the same
> results from 2 simulations using this tcl script that calls the "rand"
> function twice ?
> Thanks for any suggestion !!
> Best wishes
> vlad

Dr. Vlad Cojocaru
EML Research gGmbH
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69118 Heidelberg
Tel: ++49-6221-533202
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EML Research gGmbH
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Scientific and Managing Director: Prof. Dr.-Ing. Andreas Reuter

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