Hi Thierry,
The sparse matrix actually uses a multimodular algorithm in this case. It's
written in Cython but essentially runs at Python speed. However, that's not
where the slowness comes from. Even when running the dense matrix with that
same algorithm, it's still very fast.
I agree that fun
Sparse matrices are used by people who --like me-- solve PDEs
discretized by, say finite elements or finite volumes on irregular
meshes. In these case the matrix is sparse, that is to say it has O(n)
non zero terms, for a matrix of size n. In real computations, n can be
much more than 10^6 (10
