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Bug #23816

Random Number Generator not Seeded in GenieHelper tool

Added by Gray Putnam 11 months ago. Updated about 1 month ago.

Status:
Resolved
Priority:
Normal
Assignee:
-
Start date:
12/30/2019
Due date:
% Done:

100%

Estimated time:
Duration:

Description

The random number generator in the class in nugen responsible for emulating the FNAL beam spill timing is not seeded. This means that all neutrino generation times in a set of MC files will be identical.

The base class implementing the timing is here (nugen:source:nugen/EventGeneratorBase/GENIE/EvtTimeShiftI.cxx#L18) -- the un-seeded random generator is constructed at line 18.

The instance of this virtual class that specializes to the FNAL beam timing is here (nugen:source:nugen/EventGeneratorBase/GENIE/EvtTimeFNALBeam.cxx). It uses the default constructed random number generator and does not update it to be a seeded one.

History

#1 Updated by Gianluca Petrillo 11 months ago

  • Description updated (diff)

That is all true (TRandom3 is initialised with seed 4357 by default).
Just a reminder that all this machinery is broken anyway because it ignores the correlation between the time of the interaction and the distance of the interaction from the target.

#2 Updated by Robert Hatcher about 1 month ago

  • % Done changed from 0 to 100
  • Status changed from New to Resolved

While this redmine issue is long outstanding (2019-12-30), I think the fix is as well (made 2020-01-15)

https://cdcvs.fnal.gov/redmine/projects/nugen/repository/changes/nugen/EventGeneratorBase/GENIE/EvtTimeShiftI.cxx?rev=master
See the change 178c268f

I'd forgotten that this problem was entered as a Redmine issue; updating this to 100% done and resolved. Will close unless I hear feedback otherwise.

#3 Updated by Robert Hatcher about 1 month ago

  • % Done changed from 100 to 70
  • Status changed from Resolved to Assigned

#4 Updated by Robert Hatcher about 1 month ago

  • % Done changed from 70 to 100
  • Status changed from Assigned to Resolved

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