C 
C Program GRDPTS to generate the file containing the coordinates of all
C gridpoints of the given grid.
C
C Version: 5.40
C Date: 2000, January 22
C
C Coded by: Ludek Klimes
C     Department of Geophysics, Charles University Prague,
C     Ke Karlovu 3, 121 16 Praha 2, Czech Republic,
C     E-mail: klimes@seis.karlov.mff.cuni.cz
C
C.......................................................................
C                                                    
C Description of data files:
C
C Input data read from the standard input device (*):
C     The data are read by the list directed input (free format) and
C     consist of a single string 'SEP':
C     'SEP'...String in apostrophes containing the name of the input
C             SEP parameter or history file with the input data.
C     No default, 'SEP' must be specified and cannot be blank.
C
C                                                     
C Input data file 'SEP':
C     File 'SEP' has the form of the SEP
C     parameter file.  The parameters, which do not differ from their
C     defaults, need not be specified in file 'SEP'.
C Data specifying grid dimensions:
C     N1=positive integer... Number of gridpoints along the X1 axis.
C             Default: N1=1
C     N2=positive integer... Number of gridpoints along the X2 axis.
C             Default: N2=1
C     N3=positive integer... Number of gridpoints along the X3 axis.
C             Default: N3=1
C     O1=real... First coordinate of the grid origin (first point of the
C             grid).
C             Default: O1=0.
C     O2=real... Second coordinate of the grid origin.
C             Default: O2=0.
C     O3=real... Third coordinate of the grid origin.
C             Default: O3=0.
C     D1=real... Grid interval in the direction of the first coordinate
C             axis.
C             Default: D1=1.
C     D2=real... Grid interval in the direction of the second coordinate
C             axis.
C             Default: D2=1.
C     D3=real... Grid interval in the direction of the third coordinate
C             axis.
C             Default: D3=1.
C Name of the output file:
C     PTS='string'...Name of the output file with the coordinates
C             of the gridpoints.
C             Default: PTS='pts.out'
C
C                                                     
C Output file PTS with the gridpoints:
C (1) /
C (2) For each gridpoint data (2.1):
C (2.1) 'NNNNNN',X1,X2,X3,/
C     'NNNNNN'...  Name of the point - six-digit integer index of the
C                  gridpoint (larger grids than 999999 gridpoints are
C                  not expected to be converted into this form suitable
C                  for a reasonably small number of points).
C      X1,X2,X3... Coordinates of the gridpoint.
C (3) /
C
C-----------------------------------------------------------------------
C
      CHARACTER*80 FILSEP
      INTEGER LU0
      PARAMETER (LU0=1)
C
      CHARACTER*80 FPTS
      INTEGER LU
      PARAMETER (LU=1)
C
      CHARACTER*34 FORMAT
      INTEGER I1,I2,I3,I
      REAL X(3),X1,X2,X3,O1,O2,O3,D1,D2,D3
      EQUIVALENCE (X(1),X1),(X(2),X2),(X(3),X3)
C
C-----------------------------------------------------------------------
C
C     Reading name of SEP file with input data:
      WRITE(*,'(A)') '+GRDPTS: Enter input filename: '
      FILSEP=' '
      READ(*,*) FILSEP
      WRITE(*,'(A)') '+GRDPTS: Working ...           '
C
C     Reading all data from the SEP file into the memory:
      IF (FILSEP.NE.' ') THEN
        CALL RSEP1(LU0,FILSEP)
      ELSE
C       GRDPTS-01
        CALL ERROR('GRDPTS-01: SEP file not given')
C       Input file in the form of the SEP (Stanford Exploration Project)
C       parameter or history file must be specified.
C       There is no default filename.
      ENDIF
C
C     Reading input parameters from the SEP file:
      CALL RSEP3T('PTS',FPTS,'pts.out')
C
C     Recalling the data specifying grid dimensions
C     (arguments: Name of value in input data, Variable, Default):
      CALL RSEP3I('N1',N1,1)
      CALL RSEP3I('N2',N2,1)
      CALL RSEP3I('N3',N3,1)
      CALL RSEP3R('O1',O1,0.)
      CALL RSEP3R('O2',O2,0.)
      CALL RSEP3R('O3',O3,0.)
      CALL RSEP3R('D1',D1,1.)
      CALL RSEP3R('D2',D2,1.)
      CALL RSEP3R('D3',D3,1.)
C
C     Writing output points:
      OPEN(LU,FILE=FPTS)
      WRITE(LU,'(A)') '/'
      FORMAT(1:10)='(A,I6.6,A,'
      I=0
      DO 23 I3=0,N3-1
        X3=O3+D3*FLOAT(I3)
        DO 22 I2=0,N2-1
          X2=O2+D2*FLOAT(I2)
          DO 21 I1=0,N1-1
            X1=O1+D1*FLOAT(I1)
            I=I+1
C           Writing:
            CALL FORM2(3,X,X,FORMAT(11:34))
            WRITE(LU,FORMAT) '''',I,''' ',X1,' ',X2,' ',X3,' /'
   21     CONTINUE
   22   CONTINUE
   23 CONTINUE
      WRITE(LU,'(A)') '/'
      CLOSE(LU)
C
      WRITE(*,'(A)') '+GRDPTS: Done.                 '
      STOP
      END
C
C=======================================================================
C
      INCLUDE 'error.for'
C     error.for
      INCLUDE 'sep.for'
C     sep.for
      INCLUDE 'forms.for'
C     forms.for
      INCLUDE 'length.for'
C     length.for
C
C=======================================================================
C