te transpose of the
  matrix K), A is an N-by-N matrix, op(B) is an M-by-N matrix, U is
  an upper triangular matrix containing the Cholesky factor of the
  solution matrix X, and scale is an output scale factor, set less
  than or equal to 1 to avoid overflow in X. If matrix B has full
  rank, then the solution matrix X will be positive definite and
  hence the Cholesky factor U will be nonsingular, but if B is rank
  deficient, then X may be only positive semi-definite and U will be
  singular.

  In the 