C
C $Id: rdgrid.F,v 1.6 1998/07/16 16:40:29 jjv5 Exp arjan $
C
C------------------------------------------------------------------------
      SUBROUTINE RDGRID(IERROR)
C
C     READS IN PARAMETERS FOR GRID SUBSETTING:
C
C     GRID
C       xcore=5.6 ycore=5.7 zcore=5.6 overlap=1.0 dbuff1=2.0 dbuff2=3.1
C     END_GRID
C
C     THE ERROR FLAG IS SET TO ONE IF ANY ERRORS ARE ENCOUNTERED WHILE
C     READING THIS INFORMATION.
C
      IMPLICIT DOUBLE PRECISION (A-H,O-Z)
#include "divcon.dim"
#include "divcon.h"
C
C     LOCAL:
C
      CHARACTER LINE*80
      LOGICAL READIT(6)
C
      IERROR = 0
C
C
C     RETURN WITH AN ERROR IF THE USER HAS NOT DEFINED RESIDUES.
C
      IF(NRES.EQ.0)THEN
        IERROR = 1
C-RDC         WRITE(iout,
C-RDC      .       '(/" CANNOT DO GRID SUBSETTING UNLESS RESIDUES",
C-RDC      .                " ARE DEFINED")')
        RETURN
      ENDIF
C
      READIT(1) = .FALSE.
      READIT(2) = .FALSE.
      READIT(3) = .FALSE.
      READIT(4) = .FALSE.
      READIT(5) = .FALSE.
      READIT(6) = .FALSE.
      NREAD = 0
 100  READ(INPT,FMT='(A80)',END=1000) LINE
      CALL UPCASE1(LINE,80)
      IF(INDEX(LINE,'END_GRID').NE.0)THEN
        IF(NREAD.LT.6)THEN
          IERROR = 1
C-RDC           WRITE(iout,
C-RDC      .         '(/" SPECIFICATION OF GRID SUBSETTING",
C-RDC      .                  " PARAMETERS IS INCOMPLETE")')
        ENDIF
C     . do some consistency checking
        if (overlap.lt.0.0) then
           overlap = 0.0
        endif
        if (dgbuff2.lt.0.0) then
           dgbuff2 = 0.0
        endif
C     . shift buffers if buff2 is specified but buff1 not
        if (dgbuff1.le.0.0) then
           dgbuff1 = dgbuff2
           dgbuff2 = 0.0
        endif
        if ((overlap.ge.core(1))
     &       .or.(overlap.ge.core(2))
     &       .or.(overlap.ge.core(3))) then
C-RDC            write(iout,'(/" OVERLAP MUST BE SMALLER THAN CORE")')
           ierror = 1
        endif

c     . report subsetting data
C-RDC         write(iout,'(
C-RDC      &       //" GRID SUBSETTING PARAMETERS:",
C-RDC      &       /" --------------------------",
C-RDC      &       //"  CORE     = ",F8.4,"  * ",F8.4,"  * ",F8.4," A",
C-RDC      &       /"  OVERLAP  = ",F8.4," A",/"  DBUFF1   = ",F8.4," A",
C-RDC      &       /"  DBUFF2   = ",F8.4," A")')
C-RDC      &       core(1), core(2), core(3),overlap,dgbuff1,dgbuff2

        RETURN
      ELSE
C
C       LOOK FOR PARAMETERS.
C
        CALL WDJOIN(LINE,80,'=',IERROR)
        IF(IERROR.NE.0)THEN
C-RDC           WRITE(iout,
C-RDC      .          '(/" IMPROPER USE OF EQUALS SIGN IN GRID",
C-RDC      .                  " SUBSETTING PARAMETERS")')
          RETURN
        ENDIF
C
        ISTART = 1
 200    CALL RDWORD(LINE,ISTART,ISTOP)
C
C       IF THERE ARE NO MORE WORDS LEFT ON THIS LINE, GO BACK AND
C       READ ANOTHER LINE.
C
        IF(ISTART.EQ.0) GO TO 100
C
        IF(INDEX(LINE(ISTART:ISTOP),'XCORE=').NE.0)THEN
          IF(READIT(1)) GO TO 200
          CALL RDNUM(LINE,ISTART,core(1),IERROR)
          IF(IERROR.NE.0) GO TO 2000
          NREAD = NREAD + 1
          READIT(1) = .TRUE.
        ELSEIF(INDEX(LINE(ISTART:ISTOP),'YCORE=').NE.0)THEN
          IF(READIT(2)) GO TO 200
          CALL RDNUM(LINE,ISTART,core(2),IERROR)
          IF(IERROR.NE.0) GO TO 2000
          NREAD = NREAD + 1
          READIT(2) = .TRUE.
        ELSEIF(INDEX(LINE(ISTART:ISTOP),'ZCORE=').NE.0)THEN
          IF(READIT(3)) GO TO 200
          CALL RDNUM(LINE,ISTART,core(3),IERROR)
          IF(IERROR.NE.0) GO TO 2000
          NREAD = NREAD + 1
          READIT(3) = .TRUE.
        elseif (index(line(istart:istop),'OVERLAP=').ne.0) then
           if(readit(4)) goto 200
           call rdnum(line,istart,overlap,ierror)
           if (ierror.ne.0) goto 2000
           nread = nread + 1
           readit(4) = .true.
        ELSEIF(INDEX(LINE(ISTART:ISTOP),'DBUFF1=').NE.0)THEN
          IF(READIT(5)) GO TO 200
          CALL RDNUM(LINE,ISTART,DGBUFF1,IERROR)
          IF(IERROR.NE.0) GO TO 2000
          NREAD = NREAD + 1
          READIT(5) = .TRUE.
        ELSEIF(INDEX(LINE(ISTART:ISTOP),'DBUFF2=').NE.0)THEN
          IF(READIT(6)) GO TO 200
          CALL RDNUM(LINE,ISTART,DGBUFF2,IERROR)
          IF(IERROR.NE.0) GO TO 2000
          NREAD = NREAD + 1
          READIT(6) = .TRUE.
        ELSE
          IERROR = 1
C-RDC           WRITE(iout,
C-RDC      .         '(/" UNRECOGNIZED PARAMETER SPECIFICATION: ",
C-RDC      .          80A1)') (LINE(I:I),I=ISTART,ISTOP)
          RETURN
        ENDIF
C
C       GO BACK AND TRY TO READ ANOTHER WORD IN THIS LINE, UNLESS ALL
C       WORDS HAVE BEEN READ.
C
        IF(NREAD.LT.6)THEN
          ISTART = ISTOP + 1
          GO TO 200
        ELSE
          GO TO 100
        ENDIF
C
      ENDIF
 1000 IERROR = 1
C-RDC       WRITE(iout,
C-RDC      .     '(/" END-OF-FILE ENCOUNTERED WHILE READING GRID",
C-RDC      .              " SUBSETTING PARAMETERS")')
      RETURN
 2000 IERROR = 1
C-RDC       WRITE(iout,
C-RDC      .     '(/" ERROR READING GRID SUBSETTING PARAMETERS")')
      RETURN
      END