The QDF Format

Most input files and all output files for QHG4 have the QDF file format. QDF is a subset of the HDF5 file format, which is widely used to manage large datasets of scientific data.

HDF has a hierarchical structure of so-called groups. The top level group is designated with “/”. Every group can contain other groups, as well as attributes and data sets.

QDF uses groups to store environmental data as well as population data, and attributes to hold the parameters of a population’s action.

The structure of QDF

Groups

The top level of a qdf file can contain the following groups:

Apart from “Populations”, all groups contain only data sets and attributes. “Populations” contains one subgroup for each species involved.

Attributes

The top level of a qdf file usually contains the attributes

  • QHG

    Contains the string “A QHG4 Data File”

  • Step

    For output files, the value of this attribute is the simulation step for which the qdf file is wwritten.

  • StartTime

    The starting time of the simulation (e.g. “-75000”).

  • Info

    Arbitrary information

The root may have additional attributes but generally they are ignored.