Some basic linear algebra functionality for sparse matrices is provided: including Cholesky decomposition and backsolving as well as standard R subsetting and Kronecker products.
Versions of SparseM prior to 0.95 included a LICENSE file that described some uncertainties over the licensing status of the fortran code in src/cholesky.f. As of 9 March 2012, original authors of cholesky.f, Esmond Ng and Barry Peyton, have now, very kindly, given permission to use cholesky.f under an open source license. They have requested that their code be credited via the following two publications: Esmond G. Ng and Barry W. Peyton, "Block sparse Cholesky algorithms on advanced uniprocessor computers". SIAM J. Sci. Stat. Comput. 14 (1993), pp. 1034-1056. John R. Gilbert, Esmond G. Ng, and Barry W. Peyton, "An efficient algorithm to compute row and column counts for sparse Cholesky factorization". SIAM J. Matrix Anal. Appl. 15 (1994), pp. 1075-1091.