Program e02ahfe

!     E02AHF Example Program Text

!     Mark 29.2 Release. NAG Copyright 2023.

!     .. Use Statements ..
      Use nag_library, Only: e02ahf, e02akf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Real (Kind=nag_wp), Parameter    :: xmax = 2.5E0_nag_wp
      Real (Kind=nag_wp), Parameter    :: xmin = -0.5E0_nag_wp
      Integer, Parameter               :: nout = 6, np1 = 7
      Integer, Parameter               :: la = np1
      Integer, Parameter               :: ladif = np1
      Real (Kind=nag_wp), Parameter    :: a(la) = (/2.53213E0_nag_wp,          &
                                          1.13032E0_nag_wp,0.27150E0_nag_wp,   &
                                          0.04434E0_nag_wp,0.00547E0_nag_wp,   &
                                          0.00054E0_nag_wp,0.00004E0_nag_wp/)
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: deriv, deriv2, patm1, x
      Integer                          :: i, ifail, m
!     .. Local Arrays ..
      Real (Kind=nag_wp)               :: adif(ladif), adif2(ladif)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: real
!     .. Executable Statements ..
      Write (nout,*) 'E02AHF Example Program Results'

      ifail = 0
      Call e02ahf(np1,xmin,xmax,a,1,la,patm1,adif,1,ladif,ifail)

      ifail = 0
      Call e02ahf(np1-1,xmin,xmax,adif,1,ladif,patm1,adif2,1,ladif,ifail)

      m = 4

      Write (nout,*)
      Write (nout,*) '   I  Argument    1st deriv    2nd deriv'

      Do i = 1, m
        x = (xmin*real(m-i,kind=nag_wp)+xmax*real(i-1,kind=nag_wp))/           &
          real(m-1,kind=nag_wp)

        ifail = 0
        Call e02akf(np1-1,xmin,xmax,adif,1,ladif,x,deriv,ifail)

        ifail = 0
        Call e02akf(np1-2,xmin,xmax,adif2,1,ladif,x,deriv2,ifail)

        Write (nout,99999) i, x, deriv, deriv2
      End Do

99999 Format (1X,I4,F9.4,2(4X,F9.4))
    End Program e02ahfe