Sparse uniformly distributed random matrix
R = sprand(S)
R = sprand(m,n,density)
R = sprand(m,n,density,rc)
R = sprand(S) has the same
sparsity structure as S, but uniformly distributed random entries.
R = sprand(m,n,density) is
a random, m-by-n, sparse matrix
with approximately density*m*n uniformly distributed
nonzero entries (0 <= density <= 1).
R = sprand(m,n,density,rc) also
has reciprocal condition number approximately equal to rc. R is
constructed from a sum of matrices of rank one.
If rc is a vector of length lr,
where lr <= min(m,n), then R has rc as
its first lr singular values, all others are zero.
In this case, R is generated by random plane rotations
applied to a diagonal matrix with the given singular values. It has
a great deal of topological and algebraic structure.