C @(#)deflst.for	17.1.1.1 (ES0-DMD) 01/25/02 17:15:40
C===========================================================================
C Copyright (C) 1995 European Southern Observatory (ESO)
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 
C the 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
C GNU General Public License for more details.
C
C You should have received a copy of the GNU General Public 
C License along with this program; if not, write to the Free 
C Software Foundation, Inc., 675 Massachusetss Ave, Cambridge, 
C MA 02139, USA.
C
C Corresponding concerning ESO-MIDAS should be addressed as follows:
C	Internet e-mail: midas@eso.org
C	Postal address: European Southern Observatory
C			Data Management Division 
C			Karl-Schwarzschild-Strasse 2
C			D 85748 Garching bei Muenchen 
C			GERMANY
C===========================================================================
C
C+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
C.IDENTIFICATION
C  subroutine DEFLST          version 1.0         880901
C  A. Kruszewski              Warsaw U. Obs.
C.PURPOSE
C.INPUT/OUTPUT
C  Input parameters
C  ITOB      integer*4 array      limits of objects area
C  M         integer*4            number of objects
C  Output parameters
C  LSTP      integer*4 array      array defining regional linked lists
C  NREG      integer*4            number of regional linked lists
C
C-----------------------------------------------------------------------
      SUBROUTINE DEFLST(LSTP, ITOB, M, NREG)
C
      IMPLICIT  NONE
      INCLUDE  'MID_REL_INCL:INVENT.INC/NOLIST'
C
      INTEGER   LSTP(LPBUF)
      INTEGER   ITOB(4)
      INTEGER   M
      INTEGER   NREG
C
      INTEGER   I
      INTEGER   ISIDE
      INTEGER   IX
      INTEGER   IY
      INTEGER   KX
      INTEGER   KY
      INTEGER   NREG1
C
      DO I = 1, LPBUF
         LSTP(I) = 0.0
      ENDDO
C
      NREG1 = LPBUF / 5 - 1
      NREG = MIN ( NREG1 , M/5 )
      IX = ITOB(3) - ITOB(1) + 1
      IY = ITOB(4) - ITOB(2) + 1
      ISIDE = ( IX * IY ) / NREG
      ISIDE = INT( SQRT( FLOAT( ISIDE ) ) )
   10 CONTINUE
          KX = IX / ISIDE
          IF ( MOD( IX , ISIDE ) .GT. 0 ) THEN
              KX = KX + 1
          ENDIF
          KY = IY / ISIDE
          IF ( MOD( IY , ISIDE ) .GT. 0 ) THEN
              KY = KY + 1
          ENDIF
          IF ( KX*KY .GT. NREG1 ) THEN
              ISIDE = ISIDE + 1
              GOTO 10
          ENDIF
      NREG = KX * KY
      LSTP(1) = ISIDE
      LSTP(2) = KX
      LSTP(3) = KY
      CALL FLSTBD( NREG , LSTP , ITOB )
C
      RETURN
      END