Program c06pafe
! C06PAF Example Program Text
! Mark 30.2 Release. NAG Copyright 2024.
! .. Use Statements ..
Use nag_library, Only: c06paf, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Parameters ..
Integer, Parameter :: nin = 5, nout = 6
! .. Local Scalars ..
Integer :: ieof, ifail, j, n, nj
! .. Local Arrays ..
Real (Kind=nag_wp), Allocatable :: work(:), x(:), xx(:)
! .. Executable Statements ..
Write (nout,*) 'C06PAF Example Program Results'
! Skip heading in data file
Read (nin,*)
loop: Do
Read (nin,*,Iostat=ieof) n
If (ieof<0) Then
Exit loop
End If
Allocate (work(3*n+100),x(0:n+1),xx(0:n-1))
Read (nin,*) x(0:n-1)
xx(0:n-1) = x(0:n-1)
! ifail: behaviour on error exit
! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
Call c06paf('F',x,n,work,ifail)
Write (nout,*)
Write (nout,*) 'Components of discrete Fourier transform'
Write (nout,*)
Write (nout,*) ' Real Imag'
Write (nout,*)
Write (nout,99999)(j,x(2*j),x(2*j+1),j=0,n/2)
Do j = n/2 + 1, n - 1
nj = n - j
Write (nout,99999) j, x(2*nj), -x(2*nj+1)
End Do
Call c06paf('B',x,n,work,ifail)
Write (nout,*)
Write (nout,*) 'Original sequence as restored by inverse transform'
Write (nout,*)
Write (nout,*) ' Original Restored'
Write (nout,*)
Write (nout,99999)(j,xx(j),x(j),j=0,n-1)
Deallocate (work,x,xx)
End Do loop
99999 Format (1X,I5,2F10.5)
End Program c06pafe