[Halld-offline] HDGeant4 Meeting Minutes, January 29, 2019
marki at jlab.org
Wed Jan 30 13:34:14 EST 2019
Please find the minutes here
HDGeant4 Meeting, January 29, 2019, Minutes
* *JLab: * Alex Austregesilo, Thomas Britton, Sean Dobbs, Mark Ito
(chair), Simon Taylor, Beni Zihlmann
* *UConn: * Richard Jones
There is a recording of this meeting <https://bluejeans.com/s/LTqwb/> on
the BlueJeans site. Use your JLab credentials.
Review of minutes from last time
We went over the minutes from January 15
with no new issues raised.
How to run hdgeant without the DIRC
Richard led us through Richard's email
sent earlier today, which addressed two points:
1. How to run pre-DIRC geometry, when the DIRC is present in the master
branch of hdds
* Richard has embellished David Lawrence's mechanism whereby
hdgeant can generate its HDDS FORTRAN code and corresponding
libraries on the fly. The details are in his new HOWTO
* We discussed the utility of having HDDS XML files in the source
code repository at all. Richard stated that he finds the version
stored there useful for development.
* We also discussed the need to built legacy (pre-DIRC) versions
of HDDS on disk for general use. We thought that that might be
more trouble than they are worth. [Added in press: second
thoughts on this have been had by the secretary.]
2. How to run with the DIRC present, but not suffer the overhead of
following CKOV photons
* CKOV turns of Cerenkov photons for all detectors, i. e.,
globally. Its historical default is CKOV=1 or on. We did not pay
the computational price since no detector in the default
geometry had an index of refraction defined, a necessary
condition for optical photon tracking.
* Turning off optical photon tracking in the DIRC should speed
things up by a factor of several.
Do-over on comparison studies
Thomas presented the first plots from his effort at repeated the studies
we did when we first starting having HDGeant4 meetings. Find the plots
here <https://halldweb.jlab.org/wiki/images/9/99/Pim_1_70.pdf>. They are
all for 1 GeV/c π^− 's at 70 degrees in θ and 0 degrees in φ, and they
all show the results from HDG3 and HDG4 side-by-side (or top-and-bottom,
as the case may be). The plots and accompanying discussion appear
starting at 23:00 in the recording.
A more careful look needs to be taken. More particle settings are to
come. [Added in press: some ROOT files have been posted by Thomas:
File names have the form G[version number]_[particle]_[p GeV]_[theta
Note on Upstream Bug Fixes
Richard reported that he has passed the information on bugs he has found
in Geant4 up to the Geant4 team. He hopes to eventually be able to
operate without the "G4fixes" part of the HDGeant4 distribution.
Issues and Pull Requests on GitHub
There weren't any to review.
* This page was last modified on 30 January 2019, at 13:30.
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