C ++********************************************************************
C                                                                      *
C                                                                      *
C                                                                      *
C **********************************************************************
C=* FROM: SPIDER - MODULAR IMAGE PROCESSING SYSTEM.   AUTHOR: J.FRANK  *
C=* Copyright (C) 1985-2005  Health Research Inc.                      *
C=*                                                                    *
C=* HEALTH RESEARCH INCORPORATED (HRI),                                *   
C=* ONE UNIVERSITY PLACE, RENSSELAER, NY 12144-3455.                   *
C=*                                                                    *
C=* Email:  spider@wadsworth.org                                       *
C=*                                                                    *
C=* This program is free software; you can redistribute it and/or      *
C=* modify it under the terms of the GNU General Public License as     *
C=* published by the Free Software Foundation; either version 2 of the *
C=* License, or (at your option) any later version.                    *
C=*                                                                    *
C=* This program is distributed in the hope that it will be useful,    *
C=* but WITHOUT ANY WARRANTY; without even the implied warranty of     *
C=* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
C=* General Public License for more details.                           *
C=*                                                                    *
C=* You should have received a copy of the GNU General Public License  *
C=* along with this program; if not, write to the                      *
C=* Free Software Foundation, Inc.,                                    *
C=* 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.      *
C=*                                                                    *
C **********************************************************************
C                                                                      *
C                                                                      *
C                                                                      *
C  PURPOSE:                                                            *
C                                                                      *
C
C  SHIFT 2-D IN FOURIER SPACE WITH COPY; NO-POWER-OF-TWO DIMENSIONS
C  IF SX AND SY EQUAL ZERO THEN NO SHIFT
C
C  PARAMETERS:                                                         
C
C IMAGE_PROCESSING_ROUTINE
C
C        1         2         3         4         5         6         7
C23456789012345678901234567890123456789012345678901234567890123456789012                                                                     
C***********************************************************************

        SUBROUTINE  SHFC_2(X,Y,LSD2,NSAM,NROW,SX,SY)

        COMPLEX  X(LSD2,NROW),Y(LSD2,NROW)
        COMPLEX  R
        DOUBLE PRECISION  PI2

        IF(SX.EQ.0.0  .AND.  SY.EQ.0.0)  THEN
           CALL  COP(X,Y,2*LSD2*NROW)
           RETURN
        ENDIF
C       INS=1
C       CALL  FMRS_2(X,NSAM,NROW,INS)
C       IF(INS.EQ.0)  THEN
C       sx=0.0
C       sy=0.0
C       RETURN
C       ENDIF
        PI2=8.0*DATAN(1.0D0)
        PX=PI2*SX/FLOAT(NSAM)
        PY=PI2*SY/FLOAT(NROW)
c$omp parallel do private(i,j,arg,argy,iy,ix)
        DO    J=1,NROW
           IY=J-1
           IF(IY.GT.NROW/2)  IY=IY-NROW
           ARGY=PY*IY
           DO    I=1,LSD2
              IX=I-1
              ARG=PX*IX+ARGY
              Y(I,J)=X(I,J)*CMPLX(COS(ARG),SIN(ARG))
           ENDDO
        ENDDO
C       INS=-1
C       CALL  FMRS_2(Y,NSAM,NROW,INS)
        END