Program g13acfe

!     G13ACF Example Program Text

!     Mark 27.3 Release. NAG Copyright 2021.

!     .. Use Statements ..
      Use nag_library, Only: g13acf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6
!     .. Local Scalars ..
      Integer                          :: i, ifail, nk, nl, nvl
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: ar(:), p(:), r(:), v(:)
!     .. Executable Statements ..
      Write (nout,*) 'G13ACF Example Program Results'
      Write (nout,*)

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

!     Read in the problem size
      Read (nin,*) nk, nl

      Allocate (ar(nl),p(nl),r(nk),v(nl))

!     Read in data
      Read (nin,*)(r(i),i=1,nk)

!     Calculate partial ACF
      ifail = -1
      Call g13acf(r,nk,nl,p,v,ar,nvl,ifail)
      If (ifail/=0) Then
        If (ifail==3) Then
          Write (nout,99999) '   Only', nvl, 'valid sets were generated'
          Write (nout,*)
        Else
          Go To 100
        End If
      End If

!     Display results
      Write (nout,*) 'Lag  Partial    Predictor error  Autoregressive'
      Write (nout,*) '     autocorrn  variance ratio' // '   parameter'
      Write (nout,*)
      Write (nout,99998)(i,p(i),v(i),ar(i),i=1,nvl)

100   Continue

99999 Format (1X,A,I2,A)
99998 Format (1X,I2,F9.3,F16.3,F14.3)
    End Program g13acfe