APFEL: A PDF Evolution Library

Visit: http://apfel.hepforge.org and http://apfel.mi.infn.it/

APFEL is a library able to perform DGLAP evolution up to NNLO in QCD and to NLO in QED, both with pole and MSbar masses. The coupled DGLAP QCD+QED evolution equations are solved in x-space by means of higher order interpolations and Runge-Kutta techniques.

The APFEL library is accessible also through the APFEL Web interface. APFEL Web provides an online web-application which integrates several HEP softwares providing a complete suite plotting tools for PDFs and many related quantities (http://apfel.mi.infn.it/).

Download

You can obtain APFEL directly from the GitHub repository:

https://github.com/scarrazza/apfel/releases

For the last development version you can clone the master code:

git clone https://github.com/scarrazza/apfel.git

For the latest tag:

git tag -l
git checkout tags/tag_name

Installation

Dependencies

• Fortran and C++ compillers.
• (Optional) CMake (https://cmake.org/) > 3.16 for installation with CMake and any build system -- make, ninja, etc.
• (Optional) LHAPDF library, for support PDFs in of Les Houches format.
• (Optional) CPython headers and SWIG, for compilation of Python bindings.
• (Optional) Internet connection if the installation of PDFs was requested.

From source

Checkout the code and compile the code by using the following procedure:

cd apfel
cmake -S . -B BUILD  <extra flags>
cmake --build BUILD
cmake --install BUILD

and optionally, if the testing was enabled

ctest --test-dir BUILD

Remember to export the location of the libraries into the LD_LIBRARY_PATH or DYLD_LIBRARY_PATH.

The extra flags might be:

• generic CMake flags, e.g. -DCMAKE_INSTALL_PREFIX=/my/home/dir, -DCMAKE_Fortran_COMPILER=ifort, -DCMAKE_Fortran_FLAGS="-O2 -g", etc.
• flags pointing to the dependencies, -DPython_DIR=/where/the/derised/python/is
• flags that steer the compilation. In the current version there are the following flags:
  • -DAPFEL_ENABLE_PYTHON=ON|OFF, default=ON Enables building of python bindings. Requires SWIG and Python headers if enabled. Tested only with CPython.
  • -DAPFEL_ENABLE_TESTS=ON|OFF, default=ON Enables testing
  • -DAPFEL_ENABLE_LHAPDF=ON|OFF, default=ON Enables compilation with LHAPDF. Requires LHAPDF if enabled.
  • -DAPFEL_DOWNLOAD_PDFS=ON|OFF, default=ON Download LHAPDF sets for tests. Makes sense only when the testing and compilation with LHAPDF are enabled. Requires internet connection if enabled.
  • -DAPFEL_Python_SITEARCH=/path/to/install/python/modules|autoprefix, default is the python system location. If "autoprefix" is used, the modules will be installed inside CMAKE_INSTALL_PREFIX. Makes sense only when the building of python bindings is enabled. Do not forget to add the location of modules to the PYTHONPATH. The CMake installation also provides the CMake config files for APFEL, therefore it if possible to do in the CMakeLists.txt of the dependant projects:

find_package(apfel)
....
target_link_libraries(mytarget PRIVATE APFEL::APFEL APFEL::APFELevol)

Known issues

It is recommended to avoid using the source directory for the builds, i.e.

cmake -S . -B . # do not do this
cmake -S . # do not do this

References

• V. Bertone, S. Carrazza, J. Rojo, APFEL: A PDF Evolution Library with QED corrections, arXiv:1310.1394.
• S. Carrazza, A. Ferrara, D. Palazzo, J. Rojo, APFEL Web: a web-based application for the graphical visualization of parton distribution functions, arXiv:1410.5456.

Contact Information

Maintainers: Valerio Bertone, Stefano Carrazza

Homepage: http://apfel.hepforge.org/