Command-based scoring
Command-based scoring in Geant4 utilizes parallel navigation in a parallel
world volume as descibed in the previous sections. Through interactive commands,
the user can define :
A parallel world for scoring and three-dimensional mesh in it
Arbitrary number of physics quantities to be scored and filters
After scoring (i.e. a run), the user can visualize the score and dump
scores into a file. All available UI commands are listed in
List of built-in commands.
Command-based scoring is an optional functionality and the user has
to explicity define its use in the main().
To do this, the method G4ScoringManager::GetScoringManager()
must be invoked right after
the instantiation of G4RunManager.
A user main() to use the command-based scoring
#include "G4RunManager.hh"
#include "G4ScoringManager.hh"
int main(int argc,char** argv)
{
// Construct the run manager
G4RunManager * runManager = new G4RunManager;
// Activate command-based scorer
G4ScoringManager::GetScoringManager();
...
}
Defining a scoring mesh
To define a scoring mesh, the user has to specify the followings.
Shape and name of the 3D scoring mesh. Currently, box is the only available shape.
Size of the scoring mesh. Mesh size must be specified as "half width" similar to the
arguments of G4Box.
Number of bins for each axes. Note that too hugh number causes immense memory consumption.
Optionally, position and rotation of the mesh. If not specified, the mesh is positioned
at the center of the world volume without rotation.
For a scoring mesh the user can have arbitrary number of quantities to be scored for
each cell of the mesh.
For each scoring quantity, the use can set one filter.
Please note that /score/filter affects on the preceding scorer.
Names of scorers and filters must be unique for the mesh.
It is possible to define more than one scorer of same kind with different names
and, likely, with different filters.
Defining a scoring mesh and scores in the mesh should terminate with the
/score/close command. The following sample UI commands
define a scoring mesh named boxMesh_1, size of which is
2 m * 2 m * 2 m, and sliced into 30 cells along each axes.
For each cell energy deposition, number of steps of gamma, number of steps
of electron and number of steps of positron are scored.
UI commands to define a scoring mesh and scorers
#
# define scoring mesh
#
/score/create/boxMesh boxMesh_1
/score/mesh/boxSize 100. 100. 100. cm
/score/mesh/nBin 30 30 30
#
# define scorers and filters
#
/score/quantity/energyDeposit eDep
/score/quantity/nOfStep nOfStepGamma
/score/filter/particle gammaFilter gamma
/score/quantity/nOfStep nOfStepEMinus
/score/filter/particle eMinusFilter e-
/score/quantity/nOfStep nOfStepEPlus
/score/filter/particle ePlusFilter e+
#
/score/close
#
Drawing scores
Once scores are filled, it is possible to visualize the scores. The score is
drawn on top of the mass geometry with the current visualization settings.
By default, entries are linearly mapped to colors (gray - blue - green - red).
This color mapping is implemented in G4DefaultLinearColorMap
class, and registered to G4ScoringManager with the color map
name "defaultLinearColorMap". The user may alternate color map
by implementing a customised color map class derived from
G4VScoreColorMap and register it to
G4ScoringManager. Then, for each draw
command, one can specify the preferred color map.
Writing scores to a file
It is possible to dump a score in a mesh (/score/dumpQuantityToFile
command) or all scores in a mesh (/score/dumpAllQuantitiesToFile
command) to a file.
The default file format is the simple CSV. To alternate the file format, one should
overwrite G4VScoreWriter class and register it to
G4ScoringManager.
Please refer to /examples/extended/runAndEvent/RE03 for details.