! C06PFF Example Program Text ! Mark 24 Release. NAG Copyright 2012. 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 ! .. Parameters .. Integer, Parameter :: 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 nag_library, Only: c06pff, nag_wp Use c06pffe_mod, Only: nin, nout, readx, writx ! .. 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) Exit loop 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