SPARSEM: a subroutine package to operate with large sparse matrices. We present here a subroutine package to operate with sparse matrices stored in compact form. For each row (or column) of the matrix, just the non-null elements are stored. The package contains routines to add and multiply matrices, convert from and to normal format, etc., and is thought to be called by programs performing more complex works. We also present the results of some tests which measure the routines’ performance in comparison with standard procedures. (Source: