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       THIS SUBROUTINE WILL SHIFT AN ARRAY, A, CIRCULARLY BY IS.
C
C       CALL SHIFT1(A,b,N,IS)
C         A     REAL ARRAY OF DIMENSION N TO BE SHIFTED
c         b     output real array
C         N     DIMENSION
C         IS    INTEGER SPECIFYING SHIFT
C
C--*******************************************************************

      SUBROUTINE SHIFT1(MA,mo,M,IS)

      REAL MA(m),mo(m)

      ISH = MOD(IS,M)
      IF (ISH.LT.0) ISH = ISH+M
	m1=-ish-1+m
      DO  I = 1,m
	mo(i)=ma(mod(i+m1,m)+1)
      ENDDO
      END