A model matrix used in an example by Koenker and Ng. This is a sparse
matrix with 1850 rows and 712 columns but only 8758 non-zero entries.
It is a "dgCMatrix" object.
Usage
data(mm)
Arguments
References
Roger Koenker and Pin Ng (2003).
SparseM: A sparse matrix package for R;
J. of Statistical Software, 8 (6),
http://www.jstatsoft.org/