A generic structure for scalar and vector boundary element codes using Fortran 90

The boundary element method is an established numerical technique for the solution of the partial differential equations of potential theory and elasticity. Here we present an implementation of the method using the advanced features of Fortran 90. We show how the array, syntax, dynamic memory allocation and modularity allow the development of maintainable, readable and flexible boundary element codes. The ability to reuse large amounts of code independently of any particular integral equation is also demonstrated. Implementations for scalar and vector equations are presented, and the flexibility of the code is demonstrated by presenting multiple element types. The present implementation is illustrated by considering two numerical examples.