As a control engineer, I am always needing to use some numerical linear algebra software, usually Matlab or GNU Octave, but now that I have to write some C code using MPI for solving some linear algebra problems. There are some software packages for that so. Jochen Voss has a nice tutorial on BLAS and LAPACK at http://seehuhn.de/pages/linear I was also googling around looking for something on sparse matrix with C. I've found this thread at a forum: http://forums.aspfree.com/programming-help-33/c-initializing-a-sparse-matrix-236415.html