!   D01PAF Example Program Text
!   Mark 27.3 Release. NAG Copyright 2021.

    Module d01pafe_mod

!     D01PAF Example Program Module:
!            Parameters and User-defined Routines

!     .. Use Statements ..
      Use nag_library, Only: nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Accessibility Statements ..
      Private
      Public                           :: f
!     .. Parameters ..
      Integer, Parameter, Public       :: mxord = 5, ndim = 3, nout = 6
      Integer, Parameter, Public       :: sdvert = 2*(ndim+1)
      Integer, Parameter, Public       :: ldvert = ndim + 1
    Contains
      Function f(ndim,x)

!       .. Function Return Value ..
        Real (Kind=nag_wp)             :: f
!       .. Scalar Arguments ..
        Integer, Intent (In)           :: ndim
!       .. Array Arguments ..
        Real (Kind=nag_wp), Intent (In) :: x(ndim)
!       .. Intrinsic Procedures ..
        Intrinsic                      :: cos, exp
!       .. Executable Statements ..
        f = exp(x(1)+x(2)+x(3))*cos(x(1)+x(2)+x(3))

        Return

      End Function f
    End Module d01pafe_mod
    Program d01pafe

!     D01PAF Example Main Program

!     .. Use Statements ..
      Use d01pafe_mod, Only: f, ldvert, mxord, ndim, nout, sdvert
      Use nag_library, Only: d01paf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: esterr
      Integer                          :: ifail, j, maxord, minord, nevals
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: finvls(:), vert(:,:)
!     .. Executable Statements ..
      Write (nout,*) 'D01PAF Example Program Results'

      Allocate (finvls(mxord),vert(ldvert,sdvert))

      vert(1:ldvert,1:ndim) = 0.0_nag_wp
      Do j = 2, ldvert
        vert(j,j-1) = 1.0_nag_wp
      End Do

      minord = 0
      nevals = 1

      Do maxord = 1, mxord

        ifail = 0
        Call d01paf(ndim,vert,ldvert,sdvert,f,minord,maxord,finvls,esterr,     &
          ifail)

        If (maxord==1) Then
          Write (nout,99999)
        End If
        Write (nout,99998) maxord, finvls(maxord), esterr, nevals

        nevals = (nevals*(maxord+ndim+1))/maxord
      End Do

99999 Format (/,1X,'MAXORD   Estimated      Estimated         Integrand',/,1X, &
        '           value         accuracy        evaluations')
99998 Format (1X,I4,F13.5,E16.3,I15)
    End Program d01pafe