From: Giuseppe Battistoni (Giuseppe.Battistoni@mi.infn.it)
Date: Wed Apr 11 2007 - 12:36:16 CEST
Dear Frances,
You are always starting from the same random seed (which is the
random.dat file inside your $FLUPRO directory).w
You can obtain a different initial seed in two ways:
1) Filling a value in the WHAT(2) of the RANDOMIZ card (see the manual and
the last part of the Note in the description of this command)
2) You can collect somewhere a certain number of output seeds of FLUKA
(the files called ran**002 ran**03 etc.).
These can be used either to rename the random.dat file which is locate in
$FLUPRO, or (much better) they can be renamed according to your input file
and called by the rfluka script.
Let me make an example:
suppose that you are using an input file called frances.inp
Notice that you will obtain, as output seed from the run #1, a file
called ranfraces002.
At that point if you run again with
./flutil/rfluka -N1 -M2 frances
Then you will use ranfrances002 as a start instead of the default
random.dat (which was copied unto ranfrances001), provided that you are
including the RANDOMIZ.
Alternatively you can rename ranfrances002 into ranfrances001 and run with
the command:
./flutil/rfluka -N0 -M1 frances
Ciao
Giuseppe
On Wed, 11 Apr 2007, Burge, F (Frances) wrote:
> Dear all,
>
> I have been using the FLRNDM random number generator to sample from a
> spectrum in the source subroutine. To check that everything works as it
> should, I have been running for a small number of particles (typically
> 10) and writing the sampled energy etc to a separate file. The energy is
> sampled according to the following statement:
>
> RANDNO(NPFLKA) = FLRNDM(DUM)
> TKEFLK(NPFLKA) = (EMIN + (EMAX - EMIN) * RANDNO(NPFLKA))
>
> I have noticed that every time I run the program, I get the same
> energies sampled for the ten particles, which is a result of the same
> random numbers being used each time. Is there something I need to
> include to make sure that I get different sequences on each run?
>
> thanks,
>
> Frances
>
> Frances Burge
> Health Physicist
> 01235 778269
> Diamond Light Source Ltd.
> Rutherford Appleton Laboratory
> Chilton
> Didcot
> OX11 0DE
>
>
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