HDF5 Event File Format

HDF5 is a binary data format, organised similarly to a data base. Some modern matrix element generators support the output of parton-level events in the HDF5 format. The information is stored in the Les Houches Accord in close analogy to (default) ASCII Les Houches Event Files.

The HDF5 Les Houches event reader derives from the LHAup class and acts as a replacement of the Pythia Les Houches reader.


As the LHAHDF5 format is relatively new, no clear version numbering standard has solidified. The reader attempts at guessing the format, but there is no guarantee that the correct version can be determined. For full control, the version can be set by

word  LHAHDF5:version  
LHAHDF5 version number of the event file in the format X.Y.Z.

The Pythia-internal version numbering scheme is:

LHAHDF5 0.1.0

LHAHDF5 0.2.0

LHAHDF5 1.0.0

HDF5 Event File Usage

A number of external libraries are required to read HDF5 LHA event files. The MPICH implementation of MPI (message passing interface) is required, and its location can be specified with the --with-mpich flags passed to the configure script. Similarly, the HDF5 library and development headers are required and can be configured with the --with-hdf5 options. Finally, the HighFive header library is also required which can be configured with the --with-highfive options. Currently, version 2.2 is supported and can be downloaded as follows.
    curl -OL https://github.com/BlueBrain/HighFive/archive/v2.2.zip \ 
      && unzip v2.2.zip && mv HighFive-2.2/include/highfive . \ 
      && rm -r HighFive-2.2/ && rm v2.2.zip