Fortran 90: an entry to object-oriented programming for the solution of partial differential equations

The aim of this work is to set up a programming model suitable for numerical computing while taking benefit of Fortran 90's features. The use of concepts from object-oriented programming avoids the weaknesses of the traditional global data programming model of Fortran 77. This work supports the view that object-oriented concepts are not in contradiction with good Fortran 77 programming practices but complement them. These concepts can be embodied in a module-based programming style and result in an efficient and easy-to-maintain code (maintainability means code clarity, scope for further enhancements, and ease of debugging). After introducing the terminology associated with object-oriented programming, it is shown how these concepts are implemented in the framework of Fortran 90. Then, we present an object-oriented implementation of a spectral element solver for a Poisson equation.