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CLHEP is intended to be a set of HEP-specific foundation and utility classes such as random generators, physics vectors, geometry and linear algebra. CLHEP is structured in a set of packages independent of any external package.

Geant4 requires the CLHEP libraries in order to compile simulations. By default Geant4 distributes a minimal version of the CLHEP library sources with the toolkit to help cross-platform usage. This internal version of the CLHEP library is built and used by default, so having an external install of CLHEP is no longer a prerequisite for Geant4.

However, the BDSIM accelerator simulation toolkit, which uses Geant4 for particle-matter interactions, requires a standalone version of CLHEP to be compiled separately from Geant4. As such, the instructions below relate to the standalone version of CLHEP.


Source URL
Installed Production version (15 Mar 2016)
Source code 
Installed Development version (20 October 2017)
Central Repository

Installation Notes

The CLHEP website provides some documentation on building and installing standalone CLHEP libraries at .

According to the release notes,, the supported version of CLHEP for Geant4.10.2.p01 is Using other versions of CLHEP may produce incorrect simulation results.


When downloading software, the downloaded tarball (or other Zip archive) should be placed in an appropriately named directory in /unix/pbt/software/src: the instructions below assume that the directory is /unix/pbt/software/src/clhep. The tarball should then be extracted into the same subdirectory.

For CLHEP, the tarball is named clhep- When extracted, this produces a directory called Therefore, you will end up with a directory called /unix/pbt/software/src/clhep/ containing the CLHEP source code.

Installation from Central Repository

Once the latest version of CLHEP has been pulled from its central repository and placed within /unix/pbt/software/src/clhep/, create a build directory within the PBT Software directory from which you can compile CLHEP:

cd /unix/pbt/software/build/
mkdir clhep-
cd clhep-

CMake can then be used to compile CLHEP:

cmake ../../src/clhep/
ccmake .

The command ccmake . opens an interactive GUI that can be used to specify installation options. From within this you can define your installation directory and configure any other options as required. On the PBT cluster it is required that the software is installed to the development directory, and so the CMAKE_INSTALL_PREFIX is defined as follows:

CMAKE_INSTALL_PREFIX         /unix/pbt/software/dev/clhep-
  • c to configure
  • g to generate and exit

The software can then be installed using the usual commands:

make install

Installation from the Source Code

Source Code Extraction

cd /unix/pbt/software/src/clhep
tar -xvzf clhep-

Build And Install

Development Environment
cd /unix/pbt/software/build
mkdir -pv clhep/clhep-
cd clhep/clhep-
cmake -DCMAKE_INSTALL_PREFIX=/unix/pbt/software/dev/clhep- /unix/pbt/software/src/geant4-prerequisites/clhep/
make install
Production Environment

It may be possible to install in the production environment by running cmake again and changing the install prefix, then running make install:

cd /unix/pbt/software/build/clhep/clhep-
cmake -DCMAKE_INSTALL_PREFIX=/unix/pbt/software/prod .
make install

This will save having to compile the code again. If this does not work, the compilation steps for the development environment (above) will need to be repeated in another build directory:

cd /unix/pbt/software/build
mkdir -pv clhep/clhep-
cd clhep/clhep-
cmake -DCMAKE_INSTALL_PREFIX=/unix/pbt/software/prod /unix/pbt/software/src/clhep/
make install
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