Example description
    Program g01anfe

!     G01ANF Example Program Text
!     Mark 27.0 Release. NAG Copyright 2019.

!     .. Use Statements ..
      Use nag_library, Only: g01anf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: eps
      Integer                          :: i, ifail, ind, licomm, lrcomm, n,    &
                                          nb, np, nq, nrv, onb
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: q(:), qv(:), rcomm(:), rv(:)
      Integer, Allocatable             :: icomm(:)
!     .. Executable Statements ..
      Write (nout,*) 'G01ANF Example Program Results'
      Write (nout,*)

!     Skip heading in data file
      Read (nin,*)

!     Read in stream size and approximation factor
      Read (nin,*) n, eps

!     Read in number of elements in the output vector qv
      Read (nin,*) nq
      Allocate (qv(nq),q(nq))

!     Read in vector q
      Read (nin,*) q(1:nq)

!     Dummy allocation for the communication arrays
      lrcomm = 1
      licomm = 2
      nb = 1
      Allocate (rv(nb),rcomm(lrcomm),icomm(licomm))

!     Call NAG routine for the first time to obtain lrcomm and licomm
      ind = 0
      ifail = 0
      Call g01anf(ind,n,rv,nb,eps,np,q,qv,nq,rcomm,lrcomm,icomm,licomm,ifail)

!     Reallocate the communication arrays to the required size
      lrcomm = icomm(1)
      licomm = icomm(2)
      Deallocate (rcomm,icomm)
      Allocate (rcomm(lrcomm),icomm(licomm))

!     Read in number of vectors with dataset blocks
      Read (nin,*) nrv

      onb = 0
d_lp: Do i = 1, nrv
!       Read in number of elements in the first/next vector rv
        Read (nin,*) nb

        If (onb/=nb) Then
!         Reallocate RV if required
          Deallocate (rv)
          Allocate (rv(nb))
        End If
        onb = nb

!       Read in vector rv
        Read (nin,*) rv(1:nb)

!       Repeat calls to NAG routine for every dataset block rv
!       until n observations have been passed
        ifail = 1
        Call g01anf(ind,n,rv,nb,eps,np,q,qv,nq,rcomm,lrcomm,icomm,licomm,      &
        If (ifail/=0) Then
!         This routine is most likely to be used to process large datasets,
!         certain parameter checks will only be done once all the data has
!         been processed. Calling the routine with a hard failure (IFAIL=0)
!         would cause any processing to be lost as the program terminates.
!         It is likely that a soft failure would be more appropriate. This
!         would allow any issues with the input parameters to be resolved
!         without losing any processing already carried out.

!         In this small example we are just calling the routine again with
!         a hard failure so that the error messages are displayed.
          ifail = 0
          Call g01anf(ind,n,rv,nb,eps,np,q,qv,nq,rcomm,lrcomm,icomm,licomm,    &
        End If
        If (ind==4) Then
          Exit d_lp
        End If
      End Do d_lp

!     Call NAG routine again to calculate quantiles specified in vector q
      ind = 3
      ifail = 0
      Call g01anf(ind,n,rv,nb,eps,np,q,qv,nq,rcomm,lrcomm,icomm,licomm,ifail)

!     Print the results
      Write (nout,*) 'Input data:'
      Write (nout,99999) n, ' observations'
      Write (nout,99998) 'eps = ', eps
      Write (nout,*)
      Write (nout,*) 'Quantile     Result'
      Write (nout,99997)(q(i),qv(i),i=1,nq)

99999 Format (1X,I2,A)
99998 Format (1X,A,F5.2)
99997 Format (1X,F7.2,4X,F7.2)
    End Program g01anfe