Post midterm period

Here is a short post to say what I did during the two past weeks.

Week of June 27:

• I spent three days trying to improve the performances of my finite element scheme implementation (see my previous post and the code). Indeed, after some simple benchmarks with the Python module time, I realized that if the solution was computed in a few seconds for a refinement of 10, it took too much time for a refinement of 13 (more than one minute). At a first glance, I thought it was because I used a dense matrix and not a sparse matrix. Thus, I spent two days reading the Numpy documentation about sparse matrices, doing tests with several types of matrice (dok_matrix, lil_matrix, coo_matrix, csc_matrix, csr_matrix) and benchmarks. Unfortunately, the use of a sparse matrix didn’t improve the performances : on the contrary, they made them worse (I’m talking about the running time, not the use of memory). So finally I realized that the problem wasn’t about the use of a dense matrix but rather the four nested for loops inside the assemble method. I talked about that with my mentors and they said to me it was not such a big deal since I should focus on providing DUNE’s Python interface itself rather than performances.

• I spent two days writing the previous posts (the date on an article is not its publishing date but the date of its creation)

Week of July 03:

• I was at the PDESoft 2016, at Warwick University. I spent three days seeing the work of the DUNE community and that was interesting. I also talked IRL with my mentors about my work and what should be done for the next weeks. We agreed that I should work on adaptivity and parallelization and so I have a new milestone: implementing the finite volume scheme with a parallelized grid (see dune-grid-howto and its parfinitevolume example).

• I worked on the documentation. Powered by Sphinx, you can build it with a make doc in the build-cmake directory of dune-corepy. For now, there is the user documentation. I’m working on some documentation for the developers who may want to contribute to dune-corepy.