srand in a tclforces script

From: Vlad Cojocaru (Vlad.Cojocaru_at_eml-r.villa-bosch.de)
Date: Thu Dec 11 2008 - 06:55:53 CST

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

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e-mail:Vlad.Cojocaru[at]eml-r.villa-bosch.de
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