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  PARAMETERS:                                                         *
C
C IMAGE_PROCESSING_ROUTINE                                             *
C        0         2         3         4         5         6         7 *
C23456789012345678901234567890123456789012345678901234567890123456789012
C***********************************************************************

        SUBROUTINE  ALRQ_M
     &  (XIM,NSAM,NROW,CNS2,CNR2,NUMR,CIRC,LCIRC,NRING,MODE)

        DIMENSION  XIM(NSAM,NROW),CIRC(LCIRC)
        INTEGER  NUMR(3,NRING)
        CHARACTER*1  MODE
        DOUBLE PRECISION  PI,DFI

C
C  INTERPOLATION INTO POLAR COORDINATES
C
C        CNS2 and CNR2 are predefined centers
CC no need to set to zero, all elements are defined
Cc$omp parallel do private(i)
C        DO  10  I=1,LCIRC
C 10     CIRC(I)=0.0

        PI=2*DATAN(1.0D0)
c$omp parallel do private(i,j,inr,yq,l,lt,nsim,dfi,kcirc,
c$omp& xold,yold,fi,x,y)
        DO  I=1,NRING

C  RADIUS OF THE RING
           INR=NUMR(1,I)
           YQ=INR

           L=NUMR(3,I)
           IF(MODE.EQ.'H')  THEN
              LT=L/2
           ENDIF
           IF(MODE.EQ.'F')  THEN
              LT=L/4
           ENDIF
           NSIM=LT-1
           DFI=PI/(NSIM+1)
           KCIRC=NUMR(2,I)
           XOLD=0.0
           YOLD=INR
        CIRC(KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
           XOLD=INR
           YOLD=0.0
        CIRC(LT+KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
           IF(MODE.EQ.'F')  THEN
              XOLD=0.0
              YOLD=-INR
        CIRC(LT+LT+KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
              XOLD=-INR
              YOLD=0.0
        CIRC(LT+LT+LT+KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
           ENDIF
           DO   J=1,NSIM
              FI=DFI*J
              X=SIN(FI)*YQ
              Y=COS(FI)*YQ

              XOLD=X
              YOLD=Y
        CIRC(J+KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
              XOLD=Y
              YOLD=-X
        CIRC(J+LT+KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
              IF(MODE.EQ.'F')  THEN
                 XOLD=-X
                 YOLD=-Y
        CIRC(J+LT+LT+KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
                 XOLD=-Y
                 YOLD=X
        CIRC(J+LT+LT+LT+KCIRC)=QUADRI(XOLD+CNS2,YOLD+CNR2,NSAM,NROW,XIM)
              ENDIF
	   ENDDO
	ENDDO
c 20    CONTINUE
C
        END