! C06PFF Example Program Text
! Mark 30.1 Release. NAG Copyright 2024.
Module c06pffe_mod
! C06PFF Example Program Module:
! Parameters and User-defined Routines
! .. Use Statements ..
Use nag_library, Only: nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Accessibility Statements ..
Private
Public :: readx, writx
! .. Parameters ..
Integer, Parameter, Public :: nin = 5, nout = 6
Contains
Subroutine readx(nin,x,n1,n2)
! Read 2-dimensional complex data
! .. Scalar Arguments ..
Integer, Intent (In) :: n1, n2, nin
! .. Array Arguments ..
Complex (Kind=nag_wp), Intent (Out) :: x(n1,n2)
! .. Local Scalars ..
Integer :: i, j
! .. Executable Statements ..
Do i = 1, n1
Read (nin,*)(x(i,j),j=1,n2)
End Do
Return
End Subroutine readx
Subroutine writx(nout,x,n1,n2)
! Print 2-dimensional complex data
! .. Scalar Arguments ..
Integer, Intent (In) :: n1, n2, nout
! .. Array Arguments ..
Complex (Kind=nag_wp), Intent (In) :: x(n1,n2)
! .. Local Scalars ..
Integer :: i, j
! .. Executable Statements ..
Do i = 1, n1
Write (nout,*)
Write (nout,99999)(x(i,j),j=1,n2)
End Do
Return
99999 Format (1X,7(:,1X,'(',F6.3,',',F6.3,')'))
End Subroutine writx
End Module c06pffe_mod
Program c06pffe
! C06PFF Example Main Program
! .. Use Statements ..
Use c06pffe_mod, Only: nin, nout, readx, writx
Use nag_library, Only: c06pff, nag_wp
! .. Implicit None Statement ..
Implicit None
! .. Local Scalars ..
Integer :: ieof, ifail, l, lwork, n, ndim
! .. Local Arrays ..
Complex (Kind=nag_wp), Allocatable :: work(:), x(:)
Integer, Allocatable :: nd(:)
! .. Intrinsic Procedures ..
Intrinsic :: product
! .. Executable Statements ..
Write (nout,*) 'C06PFF Example Program Results'
! Skip heading in data file
Read (nin,*)
loop: Do
Read (nin,*,Iostat=ieof) ndim
If (ieof<0) Then
Exit loop
End If
Allocate (nd(ndim))
Read (nin,*) nd(1:ndim), l
n = product(nd(1:ndim))
lwork = n + nd(l) + 15
Allocate (x(n),work(lwork))
Call readx(nin,x,nd(1),nd(2))
Write (nout,*)
Write (nout,*) 'Original data'
Call writx(nout,x,nd(1),nd(2))
! ifail: behaviour on error exit
! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft
ifail = 0
! Compute transform
Call c06pff('F',ndim,l,nd,n,x,work,lwork,ifail)
Write (nout,*)
Write (nout,99999) 'Discrete Fourier transform of variable ', l
Call writx(nout,x,nd(1),nd(2))
! Compute inverse transform
Call c06pff('B',ndim,l,nd,n,x,work,lwork,ifail)
Write (nout,*)
Write (nout,*) 'Original sequence as restored by inverse transform'
Call writx(nout,x,nd(1),nd(2))
Deallocate (nd,x,work)
End Do loop
99999 Format (1X,A,I1)
End Program c06pffe