Most Fortran files have been reimplemented in Python by Frank Jargstorff , with native C99 implementations of the discrete integral operators. They are released this under the GPL and it is all available on his Github here : https://github.com/fjargsto/AcousticBEM and below. The example programs are under the Jupyter folder. Jupyter is a web-based program for mathematical/engineering worksheets, and together with Python and its NumPy library behaves similarly to Matlab. The worksheets can be viewed directly in Github, including their outputs/the numerical results.

AcousticBEM is a small library and example programs for solving the acoustic Helmholtz equation using the Boundary Element Method. The library is a re-implementation of the core components of Stephen Kirkup's ABEM Fortran library and its example programs. The original Fortran code and the book "The Boundary Element Method in Acoustics" are available on the website: http://www.boundary-element-method.com/.

** Directory Structure **

All the project's code is in subdirectories of the repository. The papers directory contains PDF files of the aforementioned book by S. Kirkup as well as two of his later papers relating to BEM in Acoustics.

The Fortran directory contains Kirkup's original Fortan 77 code. There are rudimentary makefile s for building the executables.

The Python subdirectory contains all the Python library code.

The C subdirectory contains C implementations of the discrete integral operators. These methods are accessible via Python native method invocation. The Python files allow configuring using these optimized versions over the Python implementation and optimized is the default setting of the code as it is checked in.

The Jupyter subdirectory contains a number of Jupyter notebooks that implement the example programs from the original Fortan library. The checked in versions contain results and can be view in Github.

**Building **

For AcousticBEM the only code requiring compilation are the integration methods and the methods implementing the discrete integral operators (L, N, M, Mt in 2D, 3D, and RAD variations). The Hankel functions used in this code are provided by the GNU Scientific Library (GSL). On an Ubuntu system this can be installed via apt-get and that is the only dependency requiring attention.

The original Fortran code also requires the GSL library, which has Fortran bindings called fgsl. The makefiles require the fgsl.mod and libfgsl.a files in a subdirectory under the Fortran directory, called fgsl .