Python is a popular scripting language with an interactive interpreter. Geant4Py, a Geant4-Python bridge, provides a bridge for Geant4 classes. This enables to directly access Geant4 classes from Python scripting. User applications can be easily configured with many Python third-party modules, such as PyROOT, on the Python software bus. Geant4Py is located in the directory environments/g4py/. Geant4Py requires Boost-C++ external library, which helps Python binding of C++ codes. A Precompiled package is available for many Linux distributions (SL, SuSE, Ubuntu, etc) and Mac OSX. Geant4 libraries can be built as "static" and "granular", where library components (variables, functions, ...) used in the application are linked statically and shipped with the application. On the other hands, in dynamic binding, the library components are not included in the application, and their binding is carried out at run time. The modular approach of Python is based on dynamic binding mechanism, so you have Geant4 shared libraries are required instead. For generic information about building Geant4 libraries, please refer to the Installation Guide. Here are some tips for manually building "global" and "shared" libraries from an already existing "static + granular" installation. After setting additional environment variables like: Environment Variable Description Value (example) G4LIB Path where the Geant4 libraries are installed $G4INSTALL/slib G4TMP Path where temporary files are placed $G4INSTALL/tmp-slib G4LIB_BUILD_SHARED Flag for building shared libraries 1 execute the following: # cd $G4INSTALL/source # make # make global In addition, it is required that all header files are installed in a single directory. # cd $G4INSTALL/source # make includes This will collect all relevant header files in $G4INSTALL/include (or $G4INCLUDE). There are additional tools for helping building a Geant4 library in the directory g4py/tools/. Geant4Py provides a configure scrtipt for building modules. # ./configure --help `configure' configures Geant4Py to adapt to many kinds of systems. Usage: ./configure SYSTEM [OPTION]... [VAR=VALUE]... SYSTEM: System type (see Supported Arhitectures) Options: -h, --help Display this help and exit Installation directories: --prefix=PREFIX Installation prefix [./] --libdir=DIR Python modules dir [PREFIX/lib] Fine tuning of the library path: --with-g4-incdir=DIR Geant4 header dir [$G4INCLUDE] --with-g4-libdir=DIR Geant4 library dir [$G4LIB/$G4SYSTEM] --with-clhep-incdir=DIR CLHEP header dir [$CLHEP_INCLUDE_DIR] --with-clhep-libdir=DIR CLHEP library dir [$CLHEP_LIB_DIR] --with-clhep-lib=LIB library name of libCLHEP.so [CLHEP|$CLHEP_LIB] --with-python-incdir=DIR Python header dir [/usr/include/python(2.#)], (location of pyconfig.h) --with-python-libdir=DIR Python library dir [/usr/lib(64)] --with-boost-incdir=DIR BOOST-C++ header dir [/usr/include], (location of boost/) --with-boost-libdir=DIR BOOST-C++ library dir [/usr/lib] --with-boost-python-lib=LIB library name of libboost_python.so [boost_python] --with-package-dir=DIR Geant4 Package dir --with-extra-dir=DIR Install path for extra packages [/usr/local] --with-xercesc-incdir=DIR Xerces-C header dir [/usr/include] --with-xercesc-libdir=DIR Xerces-C library dir [/usr/lib(64)] Enable/disable options: prefix with either --enable- or --disable- openglx OpenGLX support [auto] openglxm OpenGLXm support [disable, $G4VIS_USE_OPENGLXM] raytracerx RayTracerX support [disable, $G4VIS_USE_RAYTRACERX] Supported Architectures: linux for Linux gcc 3.x and 4.x (32bit) linux64 for Linux gcc 3.x and 4.x (64bit, alias to linuxx8664gcc) linuxx8664gcc for AMD Opteron and Intel EM64T Linux gcc 3.x and 4.x macosx for MacOSX with gcc (Tiger/Leopard and Xcode) For example, you run it like # ./configure linux64 --with-g4-incdir=/opt/heplib/Geant4/geant4.9.3/include --with-g4-libdir=/opt/heplib/Geant4/geant4.9.3/slib/Linux-g++ --with-clhep-incdir=/opt/heplib/CLHEP/2.0.4.5/include --with-clhep-libdir=/opt/heplib/CLHEP/2.0.4.5/lib --with-clhep-lib=CLHEP-2.0.4.5 The configure script automatically check your environment, and create config/config.gmk, which describes your envrionment. After executing the configure script successfully, then # make # make install PYTHONPATH environment variable should be set at tun time. PYTHONPATH environment variable indicates Python module search directories, given by a colon-separated list of directories. Practically, the variable is (your g4py directory)/lib. To use Geant4Py, you start with importing the module called "Geant4". # python Python 2.6.2 (r262:71600, Oct 24 2009, 03:15:21) [GCC 4.4.1 [gcc-4_4-branch revision 150839]] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> from Geant4 import * ************************************************************* Geant4 version Name: geant4-09-03 (18-December-2009) Copyright : Geant4 Collaboration Reference : NIM A 506 (2003), 250-303 WWW : http://cern.ch/geant4 ************************************************************* Visualization Manager instantiating... >>> When importing the Geant4 module, the G4RunManager object will be automatically instantiated. Geant4 singleton objects are also automatically instantiated. These singleton objects can be accessed by "gXXXX" variables, like "gRunManager". gLossTableManager gTerminate gApplyUICommand gMaterialTable gTrackingManager gControlExecute gNistManager gTransportationManager gElementTable gParticleIterator gUImanager gEmCalculator gParticleTable gVisManager gEventManager gProcessTable gExceptionHandler gProductionCutsTable gG4Date gRunManager gG4VERSION_NUMBER gRunManagerKernel gG4Version gStackManager gGeometryManager gStartUISession gGetCurrentValues gStateManager Once a Python object of a Geant4 class instantiated, Geant4 methods can be directly called the same way as in C++. >>> from Geant4 import * ************************************************************* Geant4 version Name: geant4-09-03 (18-December-2009) Copyright : Geant4 Collaboration Reference : NIM A 506 (2003), 250-303 WWW : http://cern.ch/geant4 ************************************************************* Visualization Manager instantiating... >>> print gRunManager.GetVersionString() Geant4 version Name: geant4-09-03 (18-December-2009) Geant4Py provides additional utility modules called "g4py" in the directory site-modules. It consists of predifined geometries, materials, physics lists, primary generator actions, and so on. The ezgeom module provides an alternative way of defining simple geometry. An example code for defining a simple geometry is shown here: import g4py.ezgeom from g4py.ezgeom import G4EzVolume def ConstructGeom(): print "* Constructing geometry..." # reset world material air= G4Material.GetMaterial("G4_AIR") g4py.ezgeom.SetWorldMaterial(air) # a target box is placed global target target= G4EzVolume("Target") au= G4Material.GetMaterial("G4_Au") target.CreateTubeVolume(au, 0., 1.*cm, 1.*mm) target.PlaceIt(G4ThreeVector(0.,0.,-10.*cm)) The NISTmaterials module provides an instant use of Geant4 NIST materials. An example code for creating NIST materials: from Geant4 import * import g4py.NISTmaterials g4py.NISTmaterials.Construct() print Geant4.gMaterialTable The ParticleGun module provides a primary generator action with G4ParticleGun. An example code is shown here: import g4py.ParticleGun # normal way for constructing user primary generator action #pgPGA= g4py.ParticleGun.ParticleGunAction() #gRunManager.SetUserAction(pgPGA) #pg= pgPGA.GetParticleGun() # 2nd way, short-cut way pg= g4py.ParticleGun.Construct() # set parameters of particle gun pg.SetParticleByName("e-") pg.SetParticleEnergy(300.*MeV) primary_position= G4ThreeVector(0.,0., -14.9*cm) primary_direction= G4ThreeVector(0.2, 0., 1.) pg.SetParticlePosition(primary_position) pg.SetParticleMomentumDirection(primary_direction) There are some examples of Geant4Py in the directories "tests/" and "examples/". In the "tests/" directory, gtest01 : exposes a user application gtest02 : test for using site-module packages gtest03 : test for ezgeom package gtest04 : test for getting command tree and command information gtest05 : test for constructing CSG geometries in Python gtest06 : test for constructing/visualizing boolean geoemtries gtest07 : test for checking overlapped geometries The "examples/" directory contains a set of examples of Geant4Py. demos/water_phantom An example of "water phantom dosimetry". This demo program shows that a Geant4 application well coworks with Root on Python front end. VisManager, PrimaryGeneratorAction, UserAction-s, histogramming with Root are implemented in Python; dose calculation in a water phantom Python overloading of user actions on-line histogramming with Root visualization education Educational examples with Graphical User Interface using TKinter * lesson1 The first version of the courseware of the mass attenuation coefficient. * lesson2 GUI interface of ExN03, which can control geometry configuration, intial particle condition, physics processes, cut value, magnetic field and visualization outputs. emplot Examples of plotting photon cross sections and stopping powers with Root. gdml Examples of writing/reading user's geometry to/from a GDML file