Using Open Source to Accelerate Development of a Finite Element-Boundary Integral Code

Open-source software has been highly influential on software development in many fields, and also has a history within computational electromagnetics. With large amounts of open-source code available, both from within computational electromagnetics and from other fields, new combinations can be made by using already existing code packages. This can be especially beneficial to developers who do not otherwise have access to a substantial codebase. In this article we describe how a finite element-boundary integral code using the adaptive cross approximation was developed by combining different existing open-source software packages with new code in Python. We provide a brief overview of the numerical methods used, but our focus is on the implementation and insights that might be useful to others who could benefit from using open-source software in their work. Three numerical examples are also presented to demonstrate accuracy, performance and use of complex materials. Our code is provided at github.com/nwingren/fe2ms both to demonstrate how the open-source packages were combined in practice, but also for those who wish to test the code themselves.