NAG Library Manual, Mark 30
Interfaces:  FL   CL   CPP   AD 

NAG FL Interface Introduction
Example description
    Program e01zmfe

!     E01ZMF Example Program Text

!     Mark 30.0 Release. NAG Copyright 2024.

!     .. Use Statements ..
      Use nag_library, Only: e01zmf, e01znf, nag_wp, x04caf
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Integer                          :: d, i, ifail, liq, lrq, m, n, nq, nw
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: f(:), q(:), qx(:,:), rq(:), x(:,:),  &
                                          xe(:,:)
      Integer, Allocatable             :: iq(:)
!     .. Executable Statements ..
      Write (nout,*) 'E01ZMF Example Program Results'

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

!     Input the number of nodes.
      Read (nin,*) d, m
      liq = 2*m + 1
      lrq = (d+1)*(d+2)/2*m + 2*d + 1
      Allocate (x(d,m),f(m),iq(liq),rq(lrq))

!     Input the data points X and F.
      Do i = 1, m
        Read (nin,*) x(1:d,i), f(i)
      End Do

!     Generate the interpolant.
      nq = 0
      nw = 0

      ifail = 0
      Call e01zmf(d,m,x,f,nw,nq,iq,rq,ifail)

!     Input the number of evaluation points.
      Read (nin,*) n
      Allocate (xe(d,n),q(n),qx(d,n))

!     Input the evaluation points.
      Do i = 1, n
        Read (nin,*) xe(1:d,i)
      End Do

!     Evaluate the interpolant using E01ZNF.
      ifail = 1
      Call e01znf(d,m,x,f,iq,rq,n,xe,q,qx,ifail)
      If (ifail==0 .Or. ifail==3) Then
        If (ifail==3) Then
          Write (nout,*) 'Some values below have been extrapolated'
          Write (nout,*)
        End If
        Write (nout,*)
        Flush (nout)
        ifail = 0
        Call x04caf('General',' ',d,n,xe,d,                                    &
          'Interpolated Evaluation Points (columns)',ifail)
        Write (nout,*)
        Flush (nout)
        Call x04caf('General',' ',1,n,q,1,'Interpolated values',ifail)
      Else
        Write (nout,99999) 'Evaluation routine returned with IFAIL = ', ifail
      End If

99999 Format (1X,A,I4)
    End Program e01zmfe