ISOFT is a piece of software/suite of tools which I developed while working on my PhD thesis to simulate the evolution of ice shelves coupled to ocean plumes. It attempts to provide an object oriented, extensible framework with which to model glacial flow using modern Fortran. Though developed for ice shelves, it could in principle be modified to simulated grounded ice dynamics as well. I've published the code and documentation to GitHub in the hopes that it might be useful to others.

As much as practical, ISOFT was kept agnostic as to whether it was handling a 1-D or a 2-D representation of an ice shelf/plume. However, the current implementation does explicitly assume a 1-D system in a number of instances and would thus need to be modified to handle 2-D problems. 1-D simulations were sufficiently fast that they could be run in serial. Multithreading could easily be implemented in many parts of the code where arithmetic is performed on arrays. Indeed, most of these cases are simple enough that a compiler may be able to parallelise them automatically. More sophisticated approaches involving message passing would likely be necessary to make 2-D simulations practical, but this would be far more difficult to implement and would likely require substantial refactoring of the code. In particular, the nonlinear solvers would likely need to be replaced.

The build-script for FORD assumes you have the libraries and header files for FFTW3, HDF5, an implementation of BLAS, and LAPACK installed on your computer. It also requires you to have the virtualenv installed. ISOFT is known to compile with gfortran v6.2 and, barring regressions, should work with all subsequent releases. There are a number of other, more obscure libraries upon which ISOFT depends, but the Makefile handles the downloading and building of these itself. You can build ISOFT on an Ubuntu-like operating system using the commands below:

sudo apt-get install libfftw3-dev libhdf5-dev libopenblas-dev liblapack-dev python-virtualenv gfortran-6
git clone --recurse-submodules https://github.com/cmacmackin/isoft
cd isoft
make lib            # Builds libisoft.a
make tests          # Builds and runs unit tests
make script         # Creates a compile-script you can use to build and
                    # link your own programs with the ISOFT library

This builds a static library which provides derived types for simulating the evolution of an ice shelf. You initialise these objects in your own programs and then call their methods to start the simulation. An example of such a program can be found in the sample file main.f90. This can be built and run as follows:

compile.sh main.f90 isoft_example
./isoft_example

The compile.sh script was generated specifically for your build of ISOFT and can be used, without modification from any directory on your computer. It's call signature is

./compile.sh [ main-file-name [ executable-name ] ]

where main-file-name is the program file to be compiled and executable-name is the name to give the resulting executable. These default to main.f90 and isoft, respectively.

Information on how to install and use ISOFT is available on GitHub Pages. This includes sections (taken from my thesis) on the numerical methods and code design choices which were made. A detailed description of the API is also provided. This documentation can be generated locally using the FORD tool. To install FORD in a virtual environment and then run it to generate the documentation, execute

make doc

If FORD is already present on your system then you can simply run

ford doc.md

ISOFT is licensed under the GNU General Public License (GPL) v3.0 or later. The terms are provided in the file LICENSE. The Lesser General Public License (LGPL) would have been used, but the Chebyshev pseudo-spectral implementation uses the FFTW3 library, which is licensed under the GPL.