C ++********************************************************************
C                                                                      *
C   ALPRBS.F                                                           *
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  ALPRBS(NUMR,NRING,LCIRC,MODE)                                                                     *
C                                                                      *
C  PURPOSE: APPEARS TO CIRCULAR RINGS, POSTITIONED
C           IN A LINEAR ARRAY THAT HOLDS RINGS CONCATENATED TOGETHER.
C           OUTPUT IS DEPENDENT ON NUMBER OF RINGS 
C                                                                      *
C  PARAMETERS:   NUMR(1,I) - RING NUMBER                      (SENT)
C                NUMR(2,I) - BEGINNING IN CIRC                (RET.)
C                NUMR(3,I) - LENGTH IN CIRC                   (RET.)
C                NRING                                        (SENT)
C                LCIRC - TOTAL LENGTH OF CIRC.                (RET.)
C
C IMAGE_PROCESSING_ROUTINE
C
C***********************************************************************

        SUBROUTINE  ALPRBS(NUMR,NRING,LCIRC,MODE)

        INCLUDE 'CMLIMIT.INC'

        INTEGER      NUMR(3,NRING)
        REAL*8       PI
        CHARACTER*1  MODE

C       PREPARATION OF PARAMETERS
        PI = 4.0*DATAN(1.0D0)
        IF (MODE.EQ.'F')  PI=2*PI

        LCIRC = 0
        DO I=1,NRING
           JP = PI*NUMR(1,I)
           IP = 2**LOG2(JP)
           IF (I.LT.NRING .AND. JP.GT.IP+IP/2)  IP=MIN0(MAXFFT,2*IP)
C          LAST RING SHOULD BE OVERSAMPLED TO ALLOW HIGHER ACCURACY
C          OF PEAK LOCATION (?).
           IF (I.EQ.NRING .AND. JP.GT.IP+IP/5)  IP=MIN0(MAXFFT,2*IP)
           NUMR(3,I) = IP
           IF (I.EQ.1)  THEN
              NUMR(2,1) = 1
           ELSE
              NUMR(2,I) = NUMR(2,I-1)+NUMR(3,I-1)
           ENDIF
           LCIRC = LCIRC + IP
        ENDDO 
        END