er of columns of the matrices B, C and D.  M &gt;= 0.

  P       (input) INTEGER
          The number of rows of the matrices A, B and D.  P &gt;= 0.

  R       (input/output) DOUBLE PRECISION array, dimension (LDR,N)
          On entry, the leading N-by-N upper triangular part of this
          array must contain the upper triangular matrix R.
          On exit, the leading N-by-N upper triangular part of this
                                                     _
          array contains the upper triangu