concise sparse matrix library

 Suitesparse is a collection of libraries for computations involving
 sparse matrices.
 .
 The CSparse library provides several matrix algorithms. The focus is on direct
 methods; iterative methods and solvers for eigenvalue problems are beyond the
 scope of this package.
 .
 The performance of the sparse factorization methods in CSparse will not be
 competitive with UMFPACK or CHOLMOD, but the codes are much more concise and
 easy to understand. Other methods are competitive.