Large sparse matrices row views do not work

[amalagaura]

Here is a failing test from parallel colt 0.10.0

  @Test
  public void testLargeSparseSum() {
    int size = 110000;
    DoubleMatrix2D m = new SparseDoubleMatrix2D(size, size);
    int i = 100000;
    assertEquals(0, m.viewRow(i).zSum(), 0.0001);
    m.set(i, i, 5);
    assertEquals(5, m.viewRow(i).zSum(), 0.0001);
  }

expected:<5.0> but was:<0.0>

m.viewRow(i).toString() :
1 x 110000 sparse matrix, nnz = 0

Strangely enough, columns work:
m.viewColumn(i).toString()

1 x 110000 sparse matrix, nnz = 1
(100000) 5.0
.get(i,i) does work as well

[rwl]

Thank you for providing a test. I should have some time at the weekend to look at this issue. Does the problem still occur with smaller matrices? Do you get the same results using one of the other sparse matrix types? For example SparseRCDoubleMatrix2D

[amalagaura]

Smaller matrices with SparseDoubleMatrix pass, the larger matrix with RC & CC pass.

We are actually having an interesting problem with the LU decomp. We ran it with a 130k square matrix, it solved in 25 seconds. Then we do some modifications, and it has been running for almost 12 hours. Both are less then 0.5% dense.

Big problem for us, I hope there are no cases which will cause it to run without stopping.

[rwl]

"Smaller matrices with SparseDoubleMatrix pass..."

Perhaps this is an integer overflow issue.

[amalagaura]

I think it is, if you see the other issue I reported with negative indices after matrix multiplication, they are likely related.