Program e01bafe

!     E01BAF Example Program Text

!     Mark 27.3 Release. NAG Copyright 2021.

!     .. Use Statements ..
      Use nag_library, Only: e01baf, e02bbf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: m = 7, nout = 6
      Integer, Parameter               :: lck = m + 4
      Integer, Parameter               :: lwrk = 6*m + 16
      Real (Kind=nag_wp), Parameter    :: x(m) = (/0.0E0_nag_wp,0.2E0_nag_wp,  &
                                          0.4E0_nag_wp,0.6E0_nag_wp,           &
                                          0.75E0_nag_wp,0.9E0_nag_wp,          &
                                          1.0E0_nag_wp/)
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: fit, xarg
      Integer                          :: ifail, j, r
!     .. Local Arrays ..
      Real (Kind=nag_wp)               :: c(lck), lamda(lck), wrk(lwrk), y(m)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: exp
!     .. Executable Statements ..
      Write (nout,*) 'E01BAF Example Program Results'

      y(1:m) = exp(x(1:m))

      ifail = 0
      Call e01baf(m,x,y,lamda,c,lck,wrk,lwrk,ifail)

      Write (nout,*)
      Write (nout,*) '   J    Knot LAMDA(J+2)   B-spline coeff C(J)'
      Write (nout,*)

      j = 1
      Write (nout,99998) j, c(1)

      Do j = 2, m - 1
        Write (nout,99999) j, lamda(j+2), c(j)
      End Do

      Write (nout,99998) m, c(m)
      Write (nout,*)
      Write (nout,*)                                                           &
        '   R        Abscissa            Ordinate             Spline'
      Write (nout,*)

      Do r = 1, m

        ifail = 0
        Call e02bbf(m+4,lamda,c,x(r),fit,ifail)

        Write (nout,99999) r, x(r), y(r), fit

        If (r<m) Then
          xarg = 0.5E0_nag_wp*(x(r)+x(r+1))

          ifail = 0
          Call e02bbf(m+4,lamda,c,xarg,fit,ifail)

          Write (nout,99997) xarg, fit
        End If

      End Do

99999 Format (1X,I4,F15.4,2F20.4)
99998 Format (1X,I4,F35.4)
99997 Format (1X,F19.4,F40.4)
    End Program e01bafe