Collection of abstracts 14th GAMM-Seminar Kiel on Concepts of Numerical Software January 23rd to 25th, 1998.

Friday, January 23rd, 1998

np - the Modular Numerical Subsystem of UG

We present the subsystem of numerical procedures of the programm-package UG.
The subsystem is designed to discretize and solve PDEs on a hierarchy of locally refined, unstructured grids. It provides a number of tools to discretize scalar or systems of linear or nonlinear PDEs by means of finite elements or finite volumes. The resulting discrete equations can be solved using a flexible modular system of configurable numerical procedures. Strictly following object-orientated design principles, the various numerical procedures have been organized as a hierarchy of classes. Depending on the problem to solve, the solver is configured by composing instances of these classes, such as 'linear iterators', 'linear solvers', 'nonlinear solvers' and 'time solvers'. Emphasis is put on the design of the different class interfaces. Finally, some examples demonstrate the flexibility of the presented system.