Program e02gafe

!     E02GAF Example Program Text

!     Mark 30.1 Release. NAG Copyright 2024.

!     .. Use Statements ..
      Use nag_library, Only: e02gaf, nag_wp
!     .. Implicit None Statement ..
      Implicit None
!     .. Parameters ..
      Integer, Parameter               :: nin = 5, nout = 6, nplus2 = 5
!     .. Local Scalars ..
      Real (Kind=nag_wp)               :: resid, t, toler
      Integer                          :: i, ifail, irank, iter, lda, m
!     .. Local Arrays ..
      Real (Kind=nag_wp), Allocatable  :: a(:,:), b(:), x(:)
      Integer, Allocatable             :: iwork(:)
!     .. Intrinsic Procedures ..
      Intrinsic                        :: exp
!     .. Executable Statements ..
      Write (nout,*) 'E02GAF Example Program Results'

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

      Read (nin,*) m
      lda = m + 2
      Allocate (a(lda,nplus2),iwork(m),b(m),x(nplus2))

      Do i = 1, m
        Read (nin,*) t, b(i)
        a(i,1) = exp(t)
        a(i,2) = exp(-t)
      End Do

      a(1:m,3) = 1.0E0_nag_wp
      toler = 0.0E0_nag_wp

      ifail = -1
      Call e02gaf(m,a,lda,b,nplus2,toler,x,resid,irank,iter,iwork,ifail)

      Select Case (ifail)
      Case (0,1)
        Write (nout,*)
        Write (nout,99999) 'Resid = ', resid, '  Rank = ', irank,              &
          '  Iterations = ', iter, '  IFAIL =', ifail
        Write (nout,*)
        Write (nout,*) 'Solution'
        Write (nout,99998) x(1:(nplus2-2))
      End Select

99999 Format (1X,A,E10.2,A,I5,A,I5,A,I5)
99998 Format (1X,6F10.4)
    End Program e02gafe