reduction.
          On exit with LTRB = .TRUE., the leading (K+N)-by-N part of
          this array contains the matrix Bout and in the zero parts
          information about the elementary reflectors.

  LDB     INTEGER
          The leading dimension of the array B.
          LDB &gt;= MAX(1,N),    if LTRB = .FALSE.;
          LDB &gt;= MAX(1,K+N),  if LTRB = .TRUE..

  G       (input/output) DOUBLE PRECISION array, dimension (LDG,N)
          On entry, the leading N-by-N part of this array must
        