This directory contains the implementation of a variable system,
that allows the description of data in simulation and their
relations.
The main module here is the tem_varSys_module, which defines the variable
system datatype and the abstract interfaces to use in the implementation
of routines for the actual implementation of variable value retrieval.

The variable system is based on the idea to use a generic C-pointer to pass
solver specific data through the interfaces to routines provided again by the
solvers.
Variables are simply identified by their label and might depend on other
variables, make use of a space-time function or simply refer to data in the
state of the solver.

In the tem_variable_module you find the description of user defined variables,
and in the tem_varMap_module, a datatype is provided that can be used to
describe a subset of variables out of variable systems.
