#3 SparseDoubleMatrix2D multiply returns dense matrix

[Marc]

Hey all, I hope all is well. I am a little confused with the behavior of SparseDoubleMatrix2D. I am using .9.4 and am calling Colt from the most recent version of scala.

When I call

val m = new SparseDoubleMatrix2D(100,100,Array.range(0,100),Array.range(0,100),1)
and then

val n = m.zMult(m,null,2,0,false,false)

I would expect that n would be a sparse matrix. Instead, it is dense with storage of all of the zeros. I have
tried the same thing through the factory method creation and again,

Thanks in advance!
m

[Marc]

Actually, I am seven more confused.

val m = DoubleFactory2D.sparse
n = m.make(4,4)
// Set n to be identity

Creating a DoubeProperty d then throws an exception when called with d.checksparse( n)

Printing out n at the REPL gives

n
res27: cern.colt.matrix.tdouble.DoubleMatrix2D =
4 x 4 sparse matrix, nnz = 4
(0,0) 1.0
(1,1) 1.0
(2,2) 1.0
(3,3) 1.0

Thanks!

[Marc]

Interestingly, checkDense(n) also throws an exception saying the matrix is not dense.. ALso, if I take n and cast it to a Sparse Matrix, I still get the exception for checkSparse()

[Marc]

More debugging, it see if I make the sparse matrix a row compressed matrix then things go through...