N routine (NF01BA and/or NF01BB). If NPRINT &lt;= 0, no
          special calls of FCN with IFLAG = 0 are made.

  U       (input) DOUBLE PRECISION array, dimension (LDU, M)
          The leading NSMP-by-M part of this array must contain the
          set of input samples,
          U = ( U(1,1),...,U(1,M); ...; U(NSMP,1),...,U(NSMP,M) ).

  LDU     INTEGER
          The leading dimension of array U.  LDU &gt;= MAX(1,NSMP).

  Y       (input) DOUBLE PRECISION array, dimension (LDY, L)
          The leading 