C++*********************************************************************
C
C FMRS_3.F                       ADDED FFTW        FEB 2000 ARDEAN LEITH
C                                FFTW3 REACTIVATED DEC 2007 ARDEAN LEITH
C                                FMRS REWRITE      JAN 2008 ARDEAN LEITH
C
C **********************************************************************
C=* FROM: SPIDER - MODULAR IMAGE PROCESSING SYSTEM.   AUTHOR: J.FRANK  *
C=* Copyright (C) 1985-2008  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  FMRS_3(A,NSAM,NROW,NSLICE,INV)
C
C  PARAMETERS:     A       ARRAY (LDA*NROW*NSLICE)        SENT/RET.
C                  INV     1=REG. FILE, -1= FOURIER FILE       SENT
C
C  D REAL MIXED RADIX FFT.
C  INPUT:  X(N) - REAL ARRAY
C  OUTPUT: N EVEN  X(N+2)
C  ORDER OF ELEMENTS:
C  R(0),0.0, R(1), I(1), R(2), I(2), ....., R(N/2-1), I(N/2-1), R(N/2),0.0
C
C         N ODD  X(N+1)
C  R(0),0.0, R(1), I(1), R(2), I(2), ....., R(N/2-1), I(N/2-1), R(N/2),I(N/2)
C 
C  HERE WE FOLLOW THE CONVENTION THAT INTEGER DIVISION 
C  IS ROUNDED DOWN, E.G. 5/2 =2)
C
C  INV: +1 FORWARD FFT
C       -1 INVERSE FFT
C
C  ON OUTPUT INV=0 MAY INDICATE ERROR (NOT GUARANTEED)!!!
C 
C--*********************************************************************

	SUBROUTINE FMRS_3(X,NSAM,NROW,NSLICE,INV)

        REAL, INTENT(INOUT)    :: X(*)
        INTEGER, INTENT(INOUT) :: INV

        CALL FMRS(X,NSAM,NROW,NSLICE, 0.0D0, 
     &            .TRUE.,.TRUE.,INV,IRTFLG)

        IF (IRTFLG .NE. 0) INV = 0

        END