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Archived Messages for CLAS_GSIM@cebaf.gov: breakup by material

breakup by material

David Rowntree (TREE@mitlns.mit.edu)
Fri, 13 Mar 1998 14:59:38 -0500 (EST)

Hello,
There is a useful Geant option for code optimization: setting STAT 1 in the
ffread.in file will give a breakup of the number of times important routines
are called by the volume type. I did that for 100 events (with AUTO 1) of the
2.4gev_p_q0.evt data file, and looked at the gtnext calls. A brief description
of the results:

The main geometry sections:
Foil: 28%
EC1: 1%
Mini: 11%
LAS2: 60%

For foil, 70% of the time is spent in the SHD1 piece, which appears to be a 25
cm long cone about the beamline.

For the LAS2, 65% is spent in one of the DC volumes (roughly equal except DC1B
which is small). About 18% in the EC, 8% in the CC, 4% in the SC, and about 6%
in the MG+MGSR pieces (ie, the magnet).

This appears to imply that cutting off particles in the magnet won't have a
major effect. A little might be gained by playing with SHD1 or the DC's, but
we mainly need a volume independent solution.

-David