        On entry, the leading N-by-N part of this array must
          contain the matrix A. If FACT = 'F', then A contains
          an upper triangular matrix S in Schur form; the elements
          below the diagonal of the array A are then not referenced.
          On exit, the leading N-by-N upper triangular part of this
          array contains the upper triangle of the matrix S.
          The contents of the array A is not modified if FACT = 'F'.

  LDA     INTEGER
          The leading dimension of 