The solver structure of FESTUNG is built around the perception that almost every solver for a PDE problem can be subdivided into three major steps:
- A setup phase: define problem parameters, read configuration files, allocate grid data structures, initialize solution vectors, etc.;
- A solver phase: assemble and solve a linear system (possibly repeatedly for different time levels), or apply iterative methods for non-linear problems, etc.;
- A post-processing phase: evaluate errors, write visualization output, etc.
In FESTUNG, these phases are split into some more fine-grained intermediate steps, allowing to implement solvers for numerical problems in a well-structured, read- and maintainable, yet efficient way, as depicted in the following flow chart:
Each of these steps is implemented as a MATLAB function, named
configureProblem, preprocessProblem, etc.
All these step functions that make up the implementation of a problem solver
are put together in a subfolder.
For an (empty) example, see the folder template, which holds a fully
working problem definition with do-nothing steps.
The implemented solver is then executed from the FESTUNG main directory using the command
main('template')where 'template' is to be replaced by the name of the folder.