bug: fixed non-finalized conversion to siesta

This was apparent for non-finalized sparsity patterns (custom made ones).

sisl/io/siesta/_help.py

@@ -26,9 +26,12 @@ def _ensure_diagonal(csr):
  # Create index arrays
  row = (csr.ncol > 0).nonzero()[0]
  row = np.repeat(row, csr.ncol[row])
+ # Ensure we only take those elements that are in play (i.e. this
+ # will work regardless of the csr being finalized or not)
+ col = csr.col[_a.array_arange(csr.ptr[:-1], n=csr.ncol, dtype=np.int32)]
 
  # figure out where they are the same (diagonals)
- present_diags = row[row == csr.col]
+ present_diags = row[row == col]
 
  # Now figure out which elements are missing
  missing_diags = np.delete(np.arange(csr.shape[0]), present_diags)