85 lines
2.9 KiB
Plaintext
85 lines
2.9 KiB
Plaintext
RUNNING THE LEM SIMULATION - A QUICK HOW-TO
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- T. Shiroka, 13.06.2008 -
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Note: G4 LEM simulations have been tested with the following versions:
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geant4-09-01 and CLHEP.2.0.3.2. To install both programs refer
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to the file geant_4.9_inst_log.txt located in the directory doc.
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Preliminary operations
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======================
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Except for the g49 command, all these operations are carried out only once:
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- Check out locally the directory:
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afs.psi.ch/project/nemu/svn/lem/trunk/simulation/geant4/LEMuSR
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located at:
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http://savannah.psi.ch/viewcvs -> nemu/lem
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- Make sure the env.sh is somewhere in your path. BEFORE starting to use
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Geant4, make sure the relevant variables are set by issuing the command:
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source /usr/local/geant4/4.9.1/env.sh
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export G4VRMLFILE_VIEWER="vrmlview" # Optional (only for VRML graphics)
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Since these commands should be use every time G4 is used, insert an alias
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in your e.g. .bashrc file (DO NOT leave gaps or insert CR!)
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alias g49='source /usr/local/geant4/4.9.1/env.sh; export G4VRMLFILE_VIEWER="vrmlview"; echo "On this machine the G4VRMLFILE_VIEWER=$G4VRMLFILE_VIEWER"'
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Each time one can prepare the G4 enviroment by simply typing: g49
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Running the macro
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=================
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The final user SHOULD compile the code only once, at the beginning.
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Then, each time a different macro is used there is NO need to compile.
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The information flow during program execution is linear:
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input data (macro) --> executable --> output data (root)
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- To run normally (output on screen, root data on file):
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lem4 1050.mac
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- To write output (output on external file, root data on file):
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lem4 1050.mac > filename.txt
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- To run interactively, comment first the macro line
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"/run/beamOn", then use a slightly modified syntax:
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lem4 1050.mac idle
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Before running the macro, edit carefully all the relevant fields
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by using the numerous existing comments as a guidance.
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Preferably use an editor capable of syntax highlighting (e.g. kate),
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and set it to the "shell script" mode.
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For a correctly running program (automatic features, etc.) all macros,
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as well as the various field maps should be located in the directory run.
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The run number at the end of the macro file name is used to save data
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automatically in a root file having the SAME name (e.g. lem4_1050.root),
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as the macro, but located under the directory run/data.
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The executable can be run even WITHOUT installing G4 (e.g. under Merlin).
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In this case, however, the user should copy the private run-time bindings
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(used by the executable) to the host machine. To list them use either:
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ldd exe_name, or
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objdump -p exe_name (more advanced)
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Analysing simulation output
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===========================
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Since most of the G4 output is written in an external root file, any root
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command, script or executable could be used for analysing data. Some root
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example files (e.g. for testing TOF, beam cross section, etc.) will be
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added soon.
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