Computer programs in a UNIX environment often use configuration files for the control of certain parameters. Usually, these parameters are stored in the home directory of the user or the directory of the program and start with a `.'. We use a similar concept for reading the parameters of ABACUS. These parameters are read from the file .abacus.
However, as ABACUS is a framework for the implementation of different algorithms, there are further requirements for the parameter concept. First, there should be a simple way for reading problem specific parameters. An extendable parameter format should relieve the user of opening and reading his own parameter files. Second, a user of our system might have several applications. It should be possible to specify parameters for different applications and to redefine application dependent parameters defined in the file .abacus.
Therefore, we provide the following parameter concept. All parameters read from the file .abacus are written into a dictionary. Application specific parameters can be specified in extra parameter files following a very simple format. For files using our parameter format we provide already an input function. The parameters read by this input function are also written to the parameter dictionary. Hence, parameters of the file .abacus can be easily redefined. Moreover, we also provide simple functions to extract the values of the parameters from the dictionary.
The parameters in .abacus include limits on the resources of the optimization
process, control of various strategies (e.g., the enumeration strategy,
the branching strategy, zero tolerances for various decisions, the amount
of output, parameters for the LP-solver).
A detailed list of parameters can be found in
Section 
.