Program e01sgfe

!     E01SGF Example Program Text

!     Mark 28.6 Release. NAG Copyright 2022.

!     .. Use Statements ..
      Use nag_library, Only: e01sgf, e01shf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Integer                          :: i, ifail, liq, lrq, m, n, nq, nw
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: f(:), q(:), qx(:), qy(:), rq(:),     &
                                          u(:), v(:), x(:), y(:)
      Integer, Allocatable             :: iq(:)
!     .. Executable Statements ..
      Write (nout,*) 'E01SGF Example Program Results'

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

!     Input the number of data points

      Read (nin,*) m
      liq = 2*m + 1
      lrq = 6*m + 5
      Allocate (x(m),y(m),f(m),iq(liq),rq(lrq))

      Do i = 1, m
        Read (nin,*) x(i), y(i), f(i)
      End Do

!     Generate the interpolant.

      nq = 0
      nw = 0

      ifail = 0
      Call e01sgf(m,x,y,f,nw,nq,iq,liq,rq,lrq,ifail)

!     Input the number of evaluation points.

      Read (nin,*) n
      Allocate (u(n),v(n),q(n),qx(n),qy(n))

      Do i = 1, n
        Read (nin,*) u(i), v(i)
      End Do

!     Evaluate the interpolant using E01SHF.

      ifail = 0
      Call e01shf(m,x,y,f,iq,liq,rq,lrq,n,u,v,q,qx,qy,ifail)

      Write (nout,*)
      Write (nout,*) '     I      U(I)      V(I)      Q(I)'

      Do i = 1, n
        Write (nout,99999) i, u(i), v(i), q(i)
      End Do

99999 Format (1X,I6,3F10.2)
    End Program e01sgfe