This repository contains the code and manuscript for research done on Sparse Physics-based and Interpretable Neural Networks for PDEs. More details are available in the following publication:

• Amuthan A. Ramabathiran and Prabhu Ramachandran^, "SPINN: Sparse, Physics-based, and partially Interpretable Neural Networks for PDEs", Journal of Computational Physics, Volume 445, pages 110600, 2021 doi:10.1016/j.jcp.2021.110600. (^ Joint first author). arXiv:2102.13037.

Running the code in this repository requires a few pre-requisites to be set up. The Python packages required are in the requirements.txt. Here are some instructions to help you set these up:

0. Setup a suitable Python distribution, using conda or a virtualenv.

1. Clone this repository:

    $ git clone https://github.com/nn4pde/SPINN.git
    $ cd SPINN

2. If you use conda, run the following from your Python environment:

    $ conda env create -f environment.yml
    $ conda activate spinn

3. If you use a virtualenv or some other Python distribution and wish to use pip:

    $ pip install -r requirements.txt

Once you install the packages you should hopefully be able to run the examples. The examples all support live-plotting of the results. Matplotlib is required for the live plotting of any of the 1D problems and Mayavi is needed for any 2D/3D problems. These are already specified in the requirements.txt and environments.yml files.

All the problems discussed in the paper are available in the code subdirectory. The supplementary text in the paper discusses the design of the code at a very high level. You can run any of the problems as follows:

  $ cd code
  $ python ode3.py -h

And this will provide a variety of help options that you can use. You can see the results live by doing:

  $ python ode3.py --plot

These require matlplotlib.

The 2D problems also feature live plotting with Mayavi if it is installed, for example:

  $ python advection1d.py --plot

You should see the solution as well as the computational nodes. Where applicable you can see an exact solution as a wireframe.

If you have a GPU and it is configured to work with PyTorch, you can use it like so:

  $ python poisson2d_irreg_dom.py --gpu

All the results shown in the paper are automated using the automan package which should already be installed as part of the above installation. This will perform all the required simulations (this can take a while) and also generate all the plots for the manuscript.

To learn how to use the automation, do this:

    $ python automate.py -h

By default the simulation outputs are in the outputs directory and the final plots for the paper are in manuscript/figures.

To generate all the figures in one go, run the following (this will take a while):

    $ python automate.py

If you wish to only run a particular set of problems and see those results you can do the following:

   $ python automate.py PROBLEM

where PROBLEM can be any of the demonstrated problems. For example:

  $ python automate.py ode1 heat cavity

Will only run those three problems. Please see the help output (-h) and look at the code for more details.

By default we do not need to use a GPU for the automation but if you have one, you can edit the automate.py and set USE_GPU = True to make use of your GPU where possible.

Once you have generated all the figures from the automation you can easily compile the manuscript. The manuscript is written with LaTeX and if you have that installed you may do the following:

$ cd manuscript
$ latexmk spinn_manuscript.tex -pdf