MODULE fft_xy !------------------------------------------------------------------------------! ! Current revisions: ! ----------------- ! ! ! Former revisions: ! ----------------- ! $Id: fft_xy.f90 392 2009-09-24 10:39:14Z weinreis $ ! ! 274 2009-03-26 15:11:21Z heinze ! Output of messages replaced by message handling routine. ! ! Feb. 2007 ! RCS Log replace by Id keyword, revision history cleaned up ! ! Revision 1.4 2006/03/28 12:27:09 raasch ! Stop when system-specific fft is selected on NEC. For unknown reasons this ! causes a program abort during first allocation in init_grid. ! ! Revision 1.2 2004/04/30 11:44:27 raasch ! Module renamed from fft_for_1d_decomp to fft_xy, 1d-routines renamed to ! fft_x and fft_y, ! function FFT replaced by subroutine FFTN due to problems with 64-bit ! mode on ibm, ! shape of array cwork is explicitly stored in ishape/jshape and handled ! to routine FFTN instead of shape-function (due to compiler error on ! decalpha), ! non vectorized FFT for nec included ! ! Revision 1.1 2002/06/11 13:00:49 raasch ! Initial revision ! ! ! Description: ! ------------ ! Fast Fourier transformation along x and y for 1d domain decomposition along x. ! Original version: Klaus Ketelsen (May 2002) !------------------------------------------------------------------------------! USE array_kind USE control_parameters USE indices USE singleton USE temperton_fft IMPLICIT NONE PRIVATE PUBLIC fft_x, fft_y, fft_init, fft_x_m, fft_y_m INTEGER, DIMENSION(:), ALLOCATABLE, SAVE :: ifax_x, ifax_y LOGICAL, SAVE :: init_fft = .FALSE. REAL, SAVE :: sqr_nx, sqr_ny REAL, DIMENSION(:), ALLOCATABLE, SAVE :: trigs_x, trigs_y #if defined( __ibm ) INTEGER, PARAMETER :: nau1 = 20000, nau2 = 22000 ! !-- The following working arrays contain tables and have to be "save" and !-- shared in OpenMP sense REAL, DIMENSION(nau1), SAVE :: aux1, auy1, aux3, auy3 #elif defined( __nec ) INTEGER, SAVE :: nz1 REAL, DIMENSION(:), ALLOCATABLE, SAVE :: trig_xb, trig_xf, trig_yb, & trig_yf #endif ! !-- Public interfaces INTERFACE fft_init MODULE PROCEDURE fft_init END INTERFACE fft_init INTERFACE fft_x MODULE PROCEDURE fft_x END INTERFACE fft_x INTERFACE fft_y MODULE PROCEDURE fft_y END INTERFACE fft_y INTERFACE fft_x_m MODULE PROCEDURE fft_x_m END INTERFACE fft_x_m INTERFACE fft_y_m MODULE PROCEDURE fft_y_m END INTERFACE fft_y_m CONTAINS SUBROUTINE fft_init IMPLICIT NONE ! !-- The following temporary working arrays have to be on stack or private !-- in OpenMP sense #if defined( __ibm ) REAL, DIMENSION(0:nx+2) :: workx REAL, DIMENSION(0:ny+2) :: worky REAL, DIMENSION(nau2) :: aux2, auy2, aux4, auy4 #elif defined( __nec ) REAL, DIMENSION(0:nx+3,nz+1) :: work_x REAL, DIMENSION(0:ny+3,nz+1) :: work_y REAL, DIMENSION(6*(nx+3),nz+1) :: workx REAL, DIMENSION(6*(ny+3),nz+1) :: worky #endif ! !-- Return, if already called IF ( init_fft ) THEN RETURN ELSE init_fft = .TRUE. ENDIF IF ( fft_method == 'system-specific' ) THEN sqr_nx = SQRT( 1.0 / ( nx + 1.0 ) ) sqr_ny = SQRT( 1.0 / ( ny + 1.0 ) ) #if defined( __ibm ) && ! defined( __ibmy_special ) ! !-- Initialize tables for fft along x CALL DRCFT( 1, workx, 1, workx, 1, nx+1, 1, 1, sqr_nx, aux1, nau1, & aux2, nau2 ) CALL DCRFT( 1, workx, 1, workx, 1, nx+1, 1, -1, sqr_nx, aux3, nau1, & aux4, nau2 ) ! !-- Initialize tables for fft along y CALL DRCFT( 1, worky, 1, worky, 1, ny+1, 1, 1, sqr_ny, auy1, nau1, & auy2, nau2 ) CALL DCRFT( 1, worky, 1, worky, 1, ny+1, 1, -1, sqr_ny, auy3, nau1, & auy4, nau2 ) #elif defined( __nec ) message_string = 'fft method "' // TRIM( fft_method) // & '" currently does not work on NEC' CALL message( 'fft_init', 'PA0187', 1, 2, 0, 6, 0 ) ALLOCATE( trig_xb(2*(nx+1)), trig_xf(2*(nx+1)), & trig_yb(2*(ny+1)), trig_yf(2*(ny+1)) ) work_x = 0.0 work_y = 0.0 nz1 = nz + MOD( nz+1, 2 ) ! odd nz slows down fft significantly ! when using the NEC ffts ! !-- Initialize tables for fft along x (non-vector and vector case (M)) CALL DZFFT( 0, nx+1, sqr_nx, work_x, work_x, trig_xf, workx, 0 ) CALL ZDFFT( 0, nx+1, sqr_nx, work_x, work_x, trig_xb, workx, 0 ) CALL DZFFTM( 0, nx+1, nz1, sqr_nx, work_x, nx+4, work_x, nx+4, & trig_xf, workx, 0 ) CALL ZDFFTM( 0, nx+1, nz1, sqr_nx, work_x, nx+4, work_x, nx+4, & trig_xb, workx, 0 ) ! !-- Initialize tables for fft along y (non-vector and vector case (M)) CALL DZFFT( 0, ny+1, sqr_ny, work_y, work_y, trig_yf, worky, 0 ) CALL ZDFFT( 0, ny+1, sqr_ny, work_y, work_y, trig_yb, worky, 0 ) CALL DZFFTM( 0, ny+1, nz1, sqr_ny, work_y, ny+4, work_y, ny+4, & trig_yf, worky, 0 ) CALL ZDFFTM( 0, ny+1, nz1, sqr_ny, work_y, ny+4, work_y, ny+4, & trig_yb, worky, 0 ) #else message_string = 'no system-specific fft-call available' CALL message( 'fft_init', 'PA0188', 1, 2, 0, 6, 0 ) #endif ELSEIF ( fft_method == 'temperton-algorithm' ) THEN ! !-- Temperton-algorithm !-- Initialize tables for fft along x and y ALLOCATE( ifax_x(nx+1), ifax_y(ny+1), trigs_x(nx+1), trigs_y(ny+1) ) CALL set99( trigs_x, ifax_x, nx+1 ) CALL set99( trigs_y, ifax_y, ny+1 ) ELSEIF ( fft_method == 'singleton-algorithm' ) THEN CONTINUE ELSE message_string = 'fft method "' // TRIM( fft_method) // & '" not available' CALL message( 'fft_init', 'PA0189', 1, 2, 0, 6, 0 ) ENDIF END SUBROUTINE fft_init SUBROUTINE fft_x( ar, direction ) !----------------------------------------------------------------------! ! fft_x ! ! ! ! Fourier-transformation along x-direction ! ! ! ! fft_x uses internal algorithms (Singleton or Temperton) or ! ! system-specific routines, if they are available ! !----------------------------------------------------------------------! IMPLICIT NONE CHARACTER (LEN=*) :: direction INTEGER :: i, ishape(1) !kk REAL, DIMENSION(:) :: ar !kk Does NOT work (Bug??) REAL, DIMENSION(0:nx) :: ar REAL, DIMENSION(0:nx+2) :: work REAL, DIMENSION(nx+2) :: work1 COMPLEX, DIMENSION(:), ALLOCATABLE :: cwork #if defined( __ibm ) REAL, DIMENSION(nau2) :: aux2, aux4 #elif defined( __nec ) REAL, DIMENSION(6*(nx+1)) :: work2 #endif IF ( fft_method == 'singleton-algorithm' ) THEN ! !-- Performing the fft with singleton's software works on every system, !-- since it is part of the model ALLOCATE( cwork(0:nx) ) IF ( direction == 'forward') then DO i = 0, nx cwork(i) = CMPLX( ar(i) ) ENDDO ishape = SHAPE( cwork ) CALL FFTN( cwork, ishape ) DO i = 0, (nx+1)/2 ar(i) = REAL( cwork(i) ) ENDDO DO i = 1, (nx+1)/2 - 1 ar(nx+1-i) = -AIMAG( cwork(i) ) ENDDO ELSE cwork(0) = CMPLX( ar(0), 0.0 ) DO i = 1, (nx+1)/2 - 1 cwork(i) = CMPLX( ar(i), -ar(nx+1-i) ) cwork(nx+1-i) = CMPLX( ar(i), ar(nx+1-i) ) ENDDO cwork((nx+1)/2) = CMPLX( ar((nx+1)/2), 0.0 ) ishape = SHAPE( cwork ) CALL FFTN( cwork, ishape, inv = .TRUE. ) DO i = 0, nx ar(i) = REAL( cwork(i) ) ENDDO ENDIF DEALLOCATE( cwork ) ELSEIF ( fft_method == 'temperton-algorithm' ) THEN ! !-- Performing the fft with Temperton's software works on every system, !-- since it is part of the model IF ( direction == 'forward' ) THEN work(0:nx) = ar CALL fft991cy( work, work1, trigs_x, ifax_x, 1, nx+1, nx+1, 1, -1 ) DO i = 0, (nx+1)/2 ar(i) = work(2*i) ENDDO DO i = 1, (nx+1)/2 - 1 ar(nx+1-i) = work(2*i+1) ENDDO ELSE DO i = 0, (nx+1)/2 work(2*i) = ar(i) ENDDO DO i = 1, (nx+1)/2 - 1 work(2*i+1) = ar(nx+1-i) ENDDO work(1) = 0.0 work(nx+2) = 0.0 CALL fft991cy( work, work1, trigs_x, ifax_x, 1, nx+1, nx+1, 1, 1 ) ar = work(0:nx) ENDIF ELSEIF ( fft_method == 'system-specific' ) THEN #if defined( __ibm ) && ! defined( __ibmy_special ) IF ( direction == 'forward' ) THEN CALL DRCFT( 0, ar, 1, work, 1, nx+1, 1, 1, sqr_nx, aux1, nau1, & aux2, nau2 ) DO i = 0, (nx+1)/2 ar(i) = work(2*i) ENDDO DO i = 1, (nx+1)/2 - 1 ar(nx+1-i) = work(2*i+1) ENDDO ELSE DO i = 0, (nx+1)/2 work(2*i) = ar(i) ENDDO DO i = 1, (nx+1)/2 - 1 work(2*i+1) = ar(nx+1-i) ENDDO work(1) = 0.0 work(nx+2) = 0.0 CALL DCRFT( 0, work, 1, work, 1, nx+1, 1, -1, sqr_nx, aux3, nau1, & aux4, nau2 ) DO i = 0, nx ar(i) = work(i) ENDDO ENDIF #elif defined( __nec ) IF ( direction == 'forward' ) THEN work(0:nx) = ar(0:nx) CALL DZFFT( 1, nx+1, sqr_nx, work, work, trig_xf, work2, 0 ) DO i = 0, (nx+1)/2 ar(i) = work(2*i) ENDDO DO i = 1, (nx+1)/2 - 1 ar(nx+1-i) = work(2*i+1) ENDDO ELSE DO i = 0, (nx+1)/2 work(2*i) = ar(i) ENDDO DO i = 1, (nx+1)/2 - 1 work(2*i+1) = ar(nx+1-i) ENDDO work(1) = 0.0 work(nx+2) = 0.0 CALL ZDFFT( -1, nx+1, sqr_nx, work, work, trig_xb, work2, 0 ) ar(0:nx) = work(0:nx) ENDIF #else message_string = 'no system-specific fft-call available' CALL message( 'fft_x', 'PA0188', 1, 2, 0, 6, 0 ) #endif ELSE message_string = 'fft method "' // TRIM( fft_method) // & '" not available' CALL message( 'fft_x', 'PA0189', 1, 2, 0, 6, 0 ) ENDIF END SUBROUTINE fft_x SUBROUTINE fft_y( ar, direction ) !----------------------------------------------------------------------! ! fft_y ! ! ! ! Fourier-transformation along y-direction ! ! ! ! fft_y uses internal algorithms (Singleton or Temperton) or ! ! system-specific routines, if they are available ! !----------------------------------------------------------------------! IMPLICIT NONE CHARACTER (LEN=*) :: direction INTEGER :: j, jshape(1) !kk REAL, DIMENSION(:) :: ar !kk Does NOT work (Bug??) REAL, DIMENSION(0:ny) :: ar REAL, DIMENSION(0:ny+2) :: work REAL, DIMENSION(ny+2) :: work1 COMPLEX, DIMENSION(:), ALLOCATABLE :: cwork #if defined( __ibm ) REAL, DIMENSION(nau2) :: auy2, auy4 #elif defined( __nec ) REAL, DIMENSION(6*(ny+1)) :: work2 #endif IF ( fft_method == 'singleton-algorithm' ) THEN ! !-- Performing the fft with singleton's software works on every system, !-- since it is part of the model ALLOCATE( cwork(0:ny) ) IF ( direction == 'forward') THEN DO j = 0, ny cwork(j) = CMPLX( ar(j) ) ENDDO jshape = SHAPE( cwork ) CALL FFTN( cwork, jshape ) DO j = 0, (ny+1)/2 ar(j) = REAL( cwork(j) ) ENDDO DO j = 1, (ny+1)/2 - 1 ar(ny+1-j) = -AIMAG( cwork(j) ) ENDDO ELSE cwork(0) = CMPLX( ar(0), 0.0 ) DO j = 1, (ny+1)/2 - 1 cwork(j) = CMPLX( ar(j), -ar(ny+1-j) ) cwork(ny+1-j) = CMPLX( ar(j), ar(ny+1-j) ) ENDDO cwork((ny+1)/2) = CMPLX( ar((ny+1)/2), 0.0 ) jshape = SHAPE( cwork ) CALL FFTN( cwork, jshape, inv = .TRUE. ) DO j = 0, ny ar(j) = REAL( cwork(j) ) ENDDO ENDIF DEALLOCATE( cwork ) ELSEIF ( fft_method == 'temperton-algorithm' ) THEN ! !-- Performing the fft with Temperton's software works on every system, !-- since it is part of the model IF ( direction == 'forward' ) THEN work(0:ny) = ar CALL fft991cy( work, work1, trigs_y, ifax_y, 1, ny+1, ny+1, 1, -1 ) DO j = 0, (ny+1)/2 ar(j) = work(2*j) ENDDO DO j = 1, (ny+1)/2 - 1 ar(ny+1-j) = work(2*j+1) ENDDO ELSE DO j = 0, (ny+1)/2 work(2*j) = ar(j) ENDDO DO j = 1, (ny+1)/2 - 1 work(2*j+1) = ar(ny+1-j) ENDDO work(1) = 0.0 work(ny+2) = 0.0 CALL fft991cy( work, work1, trigs_y, ifax_y, 1, ny+1, ny+1, 1, 1 ) ar = work(0:ny) ENDIF ELSEIF ( fft_method == 'system-specific' ) THEN #if defined( __ibm ) && ! defined( __ibmy_special ) IF ( direction == 'forward') THEN CALL DRCFT( 0, ar, 1, work, 1, ny+1, 1, 1, sqr_ny, auy1, nau1, & auy2, nau2 ) DO j = 0, (ny+1)/2 ar(j) = work(2*j) ENDDO DO j = 1, (ny+1)/2 - 1 ar(ny+1-j) = work(2*j+1) ENDDO ELSE DO j = 0, (ny+1)/2 work(2*j) = ar(j) ENDDO DO j = 1, (ny+1)/2 - 1 work(2*j+1) = ar(ny+1-j) ENDDO work(1) = 0.0 work(ny+2) = 0.0 CALL DCRFT( 0, work, 1, work, 1, ny+1, 1, -1, sqr_ny, auy3, nau1, & auy4, nau2 ) DO j = 0, ny ar(j) = work(j) ENDDO ENDIF #elif defined( __nec ) IF ( direction == 'forward' ) THEN work(0:ny) = ar(0:ny) CALL DZFFT( 1, ny+1, sqr_ny, work, work, trig_yf, work2, 0 ) DO j = 0, (ny+1)/2 ar(j) = work(2*j) ENDDO DO j = 1, (ny+1)/2 - 1 ar(ny+1-j) = work(2*j+1) ENDDO ELSE DO j = 0, (ny+1)/2 work(2*j) = ar(j) ENDDO DO j = 1, (ny+1)/2 - 1 work(2*j+1) = ar(ny+1-j) ENDDO work(1) = 0.0 work(ny+2) = 0.0 CALL ZDFFT( -1, ny+1, sqr_ny, work, work, trig_yb, work2, 0 ) ar(0:ny) = work(0:ny) ENDIF #else message_string = 'no system-specific fft-call available' CALL message( 'fft_y', 'PA0188', 1, 2, 0, 6, 0 ) #endif ELSE message_string = 'fft method "' // TRIM( fft_method) // & '" not available' CALL message( 'fft_y', 'PA0189', 1, 2, 0, 6, 0 ) ENDIF END SUBROUTINE fft_y SUBROUTINE fft_x_m( ar, direction ) !----------------------------------------------------------------------! ! fft_x_m ! ! ! ! Fourier-transformation along x-direction ! ! Version for 1d domain decomposition ! ! using multiple 1D FFT from Math Keisan on NEC ! ! or Temperton-algorithm ! ! (no singleton-algorithm on NEC because it does not vectorize) ! ! ! !----------------------------------------------------------------------! IMPLICIT NONE CHARACTER (LEN=*) :: direction INTEGER :: i, k, siza, sizw REAL, DIMENSION(0:nx,nz) :: ar REAL, DIMENSION(0:nx+3,nz+1) :: ai REAL, DIMENSION(6*(nx+4),nz+1) :: work1 #if defined( __nec ) COMPLEX, DIMENSION((nx+4)/2+1,nz+1) :: work #endif IF ( fft_method == 'temperton-algorithm' ) THEN siza = SIZE( ai, 1 ) IF ( direction == 'forward') THEN ai(0:nx,1:nz) = ar(0:nx,1:nz) ai(nx+1:,:) = 0.0 CALL fft991cy( ai, work1, trigs_x, ifax_x, 1, siza, nx+1, nz, -1 ) DO k = 1, nz DO i = 0, (nx+1)/2 ar(i,k) = ai(2*i,k) ENDDO DO i = 1, (nx+1)/2 - 1 ar(nx+1-i,k) = ai(2*i+1,k) ENDDO ENDDO ELSE DO k = 1, nz DO i = 0, (nx+1)/2 ai(2*i,k) = ar(i,k) ENDDO DO i = 1, (nx+1)/2 - 1 ai(2*i+1,k) = ar(nx+1-i,k) ENDDO ai(1,k) = 0.0 ai(nx+2,k) = 0.0 ENDDO CALL fft991cy( ai, work1, trigs_x, ifax_x, 1, siza, nx+1, nz, 1 ) ar(0:nx,1:nz) = ai(0:nx,1:nz) ENDIF ELSEIF ( fft_method == 'system-specific' ) THEN #if defined( __nec ) siza = SIZE( ai, 1 ) sizw = SIZE( work, 1 ) IF ( direction == 'forward') THEN ! !-- Tables are initialized once more. This call should not be !-- necessary, but otherwise program aborts in asymmetric case CALL DZFFTM( 0, nx+1, nz1, sqr_nx, work, nx+4, work, nx+4, & trig_xf, work1, 0 ) ai(0:nx,1:nz) = ar(0:nx,1:nz) IF ( nz1 > nz ) THEN ai(:,nz1) = 0.0 ENDIF CALL DZFFTM( 1, nx+1, nz1, sqr_nx, ai, siza, work, sizw, & trig_xf, work1, 0 ) DO k = 1, nz DO i = 0, (nx+1)/2 ar(i,k) = REAL( work(i+1,k) ) ENDDO DO i = 1, (nx+1)/2 - 1 ar(nx+1-i,k) = AIMAG( work(i+1,k) ) ENDDO ENDDO ELSE ! !-- Tables are initialized once more. This call should not be !-- necessary, but otherwise program aborts in asymmetric case CALL ZDFFTM( 0, nx+1, nz1, sqr_nx, work, nx+4, work, nx+4, & trig_xb, work1, 0 ) IF ( nz1 > nz ) THEN work(:,nz1) = 0.0 ENDIF DO k = 1, nz work(1,k) = CMPLX( ar(0,k), 0.0 ) DO i = 1, (nx+1)/2 - 1 work(i+1,k) = CMPLX( ar(i,k), ar(nx+1-i,k) ) ENDDO work(((nx+1)/2)+1,k) = CMPLX( ar((nx+1)/2,k), 0.0 ) ENDDO CALL ZDFFTM( -1, nx+1, nz1, sqr_nx, work, sizw, ai, siza, & trig_xb, work1, 0 ) ar(0:nx,1:nz) = ai(0:nx,1:nz) ENDIF #else message_string = 'no system-specific fft-call available' CALL message( 'fft_x_m', 'PA0188', 1, 2, 0, 6, 0 ) #endif ELSE message_string = 'fft method "' // TRIM( fft_method) // & '" not available' CALL message( 'fft_x_m', 'PA0189', 1, 2, 0, 6, 0 ) ENDIF END SUBROUTINE fft_x_m SUBROUTINE fft_y_m( ar, ny1, direction ) !----------------------------------------------------------------------! ! fft_y_m ! ! ! ! Fourier-transformation along y-direction ! ! Version for 1d domain decomposition ! ! using multiple 1D FFT from Math Keisan on NEC ! ! or Temperton-algorithm ! ! (no singleton-algorithm on NEC because it does not vectorize) ! ! ! !----------------------------------------------------------------------! IMPLICIT NONE CHARACTER (LEN=*) :: direction INTEGER :: j, k, ny1, siza, sizw REAL, DIMENSION(0:ny1,nz) :: ar REAL, DIMENSION(0:ny+3,nz+1) :: ai REAL, DIMENSION(6*(ny+4),nz+1) :: work1 #if defined( __nec ) COMPLEX, DIMENSION((ny+4)/2+1,nz+1) :: work #endif IF ( fft_method == 'temperton-algorithm' ) THEN siza = SIZE( ai, 1 ) IF ( direction == 'forward') THEN ai(0:ny,1:nz) = ar(0:ny,1:nz) ai(ny+1:,:) = 0.0 CALL fft991cy( ai, work1, trigs_y, ifax_y, 1, siza, ny+1, nz, -1 ) DO k = 1, nz DO j = 0, (ny+1)/2 ar(j,k) = ai(2*j,k) ENDDO DO j = 1, (ny+1)/2 - 1 ar(ny+1-j,k) = ai(2*j+1,k) ENDDO ENDDO ELSE DO k = 1, nz DO j = 0, (ny+1)/2 ai(2*j,k) = ar(j,k) ENDDO DO j = 1, (ny+1)/2 - 1 ai(2*j+1,k) = ar(ny+1-j,k) ENDDO ai(1,k) = 0.0 ai(ny+2,k) = 0.0 ENDDO CALL fft991cy( ai, work1, trigs_y, ifax_y, 1, siza, ny+1, nz, 1 ) ar(0:ny,1:nz) = ai(0:ny,1:nz) ENDIF ELSEIF ( fft_method == 'system-specific' ) THEN #if defined( __nec ) siza = SIZE( ai, 1 ) sizw = SIZE( work, 1 ) IF ( direction == 'forward') THEN ! !-- Tables are initialized once more. This call should not be !-- necessary, but otherwise program aborts in asymmetric case CALL DZFFTM( 0, ny+1, nz1, sqr_ny, work, ny+4, work, ny+4, & trig_yf, work1, 0 ) ai(0:ny,1:nz) = ar(0:ny,1:nz) IF ( nz1 > nz ) THEN ai(:,nz1) = 0.0 ENDIF CALL DZFFTM( 1, ny+1, nz1, sqr_ny, ai, siza, work, sizw, & trig_yf, work1, 0 ) DO k = 1, nz DO j = 0, (ny+1)/2 ar(j,k) = REAL( work(j+1,k) ) ENDDO DO j = 1, (ny+1)/2 - 1 ar(ny+1-j,k) = AIMAG( work(j+1,k) ) ENDDO ENDDO ELSE ! !-- Tables are initialized once more. This call should not be !-- necessary, but otherwise program aborts in asymmetric case CALL ZDFFTM( 0, ny+1, nz1, sqr_ny, work, ny+4, work, ny+4, & trig_yb, work1, 0 ) IF ( nz1 > nz ) THEN work(:,nz1) = 0.0 ENDIF DO k = 1, nz work(1,k) = CMPLX( ar(0,k), 0.0 ) DO j = 1, (ny+1)/2 - 1 work(j+1,k) = CMPLX( ar(j,k), ar(ny+1-j,k) ) ENDDO work(((ny+1)/2)+1,k) = CMPLX( ar((ny+1)/2,k), 0.0 ) ENDDO CALL ZDFFTM( -1, ny+1, nz1, sqr_ny, work, sizw, ai, siza, & trig_yb, work1, 0 ) ar(0:ny,1:nz) = ai(0:ny,1:nz) ENDIF #else message_string = 'no system-specific fft-call available' CALL message( 'fft_y_m', 'PA0188', 1, 2, 0, 6, 0 ) #endif ELSE message_string = 'fft method "' // TRIM( fft_method) // & '" not available' CALL message( 'fft_x_m', 'PA0189', 1, 2, 0, 6, 0 ) ENDIF END SUBROUTINE fft_y_m END MODULE fft_xy