MCStepLogger

This page gives an overview of the basic functionality of the MCStepLogger. For a more in-depth description, please refer to the package's readme. The MCStepLogger can be used to log and analyse the single steps computed by detector simulation engines built upon the Virtual Monte Carlo (VMC).

When using it with O2 simulations, make sure to use o2-sim-serial instead of o2-sim.

Basic usage

LD_PRELOAD=path_to/libMCStepLoggerInterceptSteps.so o2-sim-serial -m PIPE ITS TPC -n 10

[MCLOGGER:] START FLUSHING ----
[STEPLOGGER]: did 28 steps
[STEPLOGGER]: transported 1 different tracks
[STEPLOGGER]: transported 1 different types
[STEPLOGGER]: VolName cave COUNT 23 SECONDARIES 0
[STEPLOGGER]: VolName normalPCB1 COUNT 3 SECONDARIES 0
[STEPLOGGER]: ----- END OF EVENT ------
[FIELDLOGGER]: did 21 steps
[FIELDLOGGER]: VolName cave COUNT 20
[FIELDLOGGER]: ----- END OF EVENT ------
[MCLOGGER:] END FLUSHING ----

The stepping logger information can also be directed to an output tree for more detailed investigations. The default output file name is MCStepLoggerOutput.root (and can be changed by setting the MCSTEPLOG_OUTFILE env variable). To enable this functionality, do

MCSTEPLOG_TTREE=1 LD_PRELOAD=path_to/libMCStepLogger.so o2-sim-serial ...

Special case on macOS

LD_PRELOAD must be replaced by DYLD_INSERT_LIBRARIES, e.g. :

DYLD_INSERT_LIBRARIES=/Users/laurent/alice/sw/osx_x86-64/O2/latest-clion-o2/lib/libMCStepLogger.dylib MCSTEPLOG_TTREE=1 MCSTEPLOG_OUTFILE=toto.root o2-sim-serial -m MCH -g fwmugen -n 1

LD_DEBUG=libs must be replaced by DYLD_PRINT_LIBRARIES=1

LD_DEBUG=statistics must be replaced by DYLD_PRINT_STATISTICS=1