C++*********************************************************************
C
C  ADDFAC.F                 NEW                    MAR 03  ARDEAN LEITH
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  ADDFAC(VOLBUF,LUNIN,IFORMT,NSAM,NROW,NSLICE,SIGN,FACT1,FACT2)
C
C  PURPOSE:  ADD, SUBTRACT, OR MULTIPLY IMAGES WITH FACTORS
C            BOTH IMAGES HAVE TO HAVE THE SAME SIZE.
C
C  PARAMETERS:     
C        VOLBUF       INPUT VOLUME (#1)
C        LUNIN        I/O UNIT NUMBER OF INPUT FILE #2
C        IFORMT       IFORM OF INPUT VOLUME
C        NSAM,NROW    X & Y DIMENSIONS OF IMAGES
C        NSLICE       Z DIMENSION OF IMAGES
C        SIGN        +1000  1 IS ADDED/SUBTRACTED TO 2
C                    +2000  1 IS MULTIPLIED WITH 2 with ratio
C                          
C23456789012345678901234567890123456789012345678901234567890123456789012
C--*********************************************************************

        SUBROUTINE ADDFAC(VOLBUF,LUNIN,IFORMT,NSAM,NROW,NSLICE,SIGN,
     &                 FACT1,FACT2)

        INCLUDE 'CMBLOCK.INC'
        INCLUDE 'CMLIMIT.INC'

        REAL,DIMENSION(*) :: VOLBUF
        LOGICAL :: RATIO

        COMMON /IOBUF/ BUF(NBUFSIZ)

	NREC  = NROW * NSLICE
        ILOC  = 0

	IF (SIGN .EQ. 1000.0)  THEN
C          2 TIMES FACT2 IS ADDED TO 1 * FACT1

           DO IREC=1,NREC
              CALL REDLIN(LUNIN,BUF,NSAM,IREC)
              DO  ISAM=1,NSAM
                  ILOC         = ILOC + 1
                  VOLBUF(ILOC) = VOLBUF(ILOC) * FACT1 + 
     &                           BUF(ISAM)    * FACT2
                ENDDO
           ENDDO
           	
	ELSE
C          RATIO OF 1 TO 2 TIMES FACT2 IS ADDED TO 1 * FACT1

           DO IREC=1,NREC
              CALL REDLIN(LUNIN,BUF,NSAM,IREC)
              DO  ISAM=1,NSAM
                ILOC         = ILOC + 1
                VOLBUF(ILOC) = VOLBUF(ILOC) * FACT1 + 
     &                        (VOLBUF(ILOC) / BUF(ISAM)) * FACT2
              ENDDO
            ENDDO
        ENDIF

        RETURN
        END