Set<Integer> diags = new TreeSet<Integer>();
for (int i = 0; i < size.numEntries(); ++i)
diags.add(getDiagonal(row[i], column[i]));
if (info.isSymmetric() || info.isSkewSymmetric())
for (int i = 0; i < size.numEntries(); ++i)
if (row[i] != column[i])
diags.add(getDiagonal(column[i], row[i]));
// Convert into an integer array
int[] ind = new int[diags.size()];