Support #814

Random seed question in MAUS simulation

Added by Rogers, Chris over 12 years ago. Updated over 12 years ago.

Belozertseva, Anastasia
Target version:
Start date:
06 December 2011
Due date:
% Done:


Estimated time:
In Development


Email from Anastasia:

I hope things are going well over there.

So, I recently came across the following dilemma: When I run the
simulation, and attempt to produce space points, all of the points
generated are the same (i.e. I get like 9 unique values for the hits, and
then the same 9 values start over, start over, start over, etc.). I have
run into the same problem a while ago (over the summer, before the latest
changes in the simulation), and back then going into
src/common_cpp/Simulation/ and setting seed =
clock() at the end of the file (line 147) fixed the issue -> I would get
all unique hits and no repeats ever. Do you by any chance know why this is
not working for me anymore and do you maybe know of any possible solutions
to the issue?

Files (7.61 KB) Belozertseva, Anastasia, 06 December 2011 21:39
output (2.07 MB) output Belozertseva, Anastasia, 06 December 2011 21:39

Updated by Rogers, Chris over 12 years ago

You shouldn't do it like this.

The beam is constructed using the beam parameters in ConfigurationDefaults. If you set the random_seed_algorithm to incrementing_random, this should change the random seed for each successive particle. If not, please let me know - that is a bug.


Updated by Rogers, Chris over 12 years ago

  • Workflow changed from New Issue to In Development

Updated by Belozertseva, Anastasia over 12 years ago

My random_seed_algorithm is definitely set to incrementing_random, so I think this might be a bug.. I am attaching my datacards and the output just in case, so that you know what I am actually talking about. I am running a pencil beam of 1 GeV, with no magnetic field and no mcs/energy loss.


Updated by Rogers, Chris over 12 years ago

Sorry for the delay in looking at this. You set physics model to "none". This disables random physics processes - so the monte carlo is deterministic.

Try setting physics model to "standard"... which enables the random processes. Let me know if this fixes the issue.


Updated by Rogers, Chris over 12 years ago

  • Status changed from Open to Rejected

No update so reject..

Also available in: Atom PDF