Program g10acfe

!     G10ACF Example Program Text

!     Mark 29.2 Release. NAG Copyright 2023.

!     .. Use Statements ..
      Use nag_library, Only: g10acf, g10zaf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: crit, df, rho, rss, tol, u
      Integer                          :: i, ifail, ldc, lwk, lwt, maxcal, n,  &
                                          nord
      Character (1)                    :: method, weight
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: c(:,:), h(:), res(:), wk(:), wt(:),  &
                                          wwt(:), x(:), xord(:), y(:),         &
                                          yhat(:), yord(:)
      Integer, Allocatable             :: iwrk(:)
!     .. Executable Statements ..
      Write (nout,*) 'G10ACF Example Program Results'
      Write (nout,*)

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

      If (weight=='W' .Or. weight=='w') Then
        lwt = n
      Else
        lwt = 0
      End If
      ldc = n - 1
      lwk = 7*(n+2)
      Allocate (x(n),y(n),wt(lwt),xord(n),yord(n),wwt(n),yhat(n),c(ldc,3),     &
        res(n),h(n),wk(lwk),iwrk(n))

!     Read in data
      If (lwt>0) Then
        Read (nin,*)(x(i),y(i),wt(i),i=1,n)
      Else
        Read (nin,*)(x(i),y(i),i=1,n)
      End If

!     Read in control parameters
      Read (nin,*) u, tol, maxcal, crit

!     Sort data, removing ties and weighting accordingly
      ifail = 0
      Call g10zaf(weight,n,x,y,wt,nord,xord,yord,wwt,rss,iwrk,ifail)

!     Fit cubic spline
      ifail = 0
      Call g10acf(method,'W',nord,xord,yord,wwt,yhat,c,ldc,rss,df,res,h,crit,  &
        rho,u,tol,maxcal,wk,ifail)

!     Display results
      Write (nout,99999) 'Residual sum of squares = ', rss
      Write (nout,99999) 'Degrees of freedom = ', df
      Write (nout,99999) 'RHO = ', rho
      Write (nout,*)
      Write (nout,*) '     Input data                Output results'
      Write (nout,*) '   I    X       Y            YHAT      H'
      Write (nout,99998)(i,xord(i),yord(i),yhat(i),h(i),i=1,nord)

99999 Format (1X,A,F10.2)
99998 Format (I4,2F8.3,6X,2F8.3)
    End Program g10acfe