C
C Program CRTRAY converting the unformatted output of program CRT into
C formatted files with rays suitable for plotting.
C
C Version: 5.80
C Date: 2003, August 14
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 This simple conversion program may serve as an example how to read and
C process output files of the complete ray tracing program CRT.
C Reading the output files is completed by a simple invocation of
C subroutine AP00 of file 'ap.for', called by means of subroutine CRTOUT
C of file 'crtout.for'.
C
C The structure of the output file with rays is an extension of the
C general file form LINES
C designed to store 3-D curves, e.g., for the purposes of plotting.
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 Names of the input and output files:
C     CRTOUT='string'... File with the names of the output files of
C             program CRT. A single set of CRT output files is read
C             from CRTOUT.  Only the files 'CRT-R', and 'CRT-I' are
C             read by CRTRAY.
C             For general description of file CRTOUT refer to file
C             
C             writ.for.
C             Default: CRTOUT=' ' which means 'CRT-R'='r01.out',
C                      'CRT-I'='r01i.out'
C     REC='string' ... If non-blank, the name of the file with the
C             names of the receiver points.  The names are then used
C             within the strings describing the two-point rays.
C             Otherwise, the two-point rays are denoted by the receiver
C             index.
C             Description of file
C             REC.
C             Default: REC=' '
C     SRC='string' ... If non-blank, the name of the file with the
C             name of the source point.  The name is then used within
C             the strings describing the rays.
C             Description of file
C             SRC.
C             Default: SRC=' '
C     RAYS='string' ... Name of the output formatted file with rays.
C             This file is designed, for instance, as an input file for
C             plotting rays.
C             Description of file
C             RAYS.
C             Default: RAYS='rays.out'
C Parameters describing the form of output file RAYS:
C     NQ=integer ... Number of reals in each line of output file RAYS.
C             If NQ exceeds parameter MQ (see the code below), it is set
C             to MQ.
C             The output reals represent:
C             1. X1-coordinate.
C             2. X2-coordinate.
C             3. X3-coordinate.
C             4. Travel time.
C             5. P1 slowness-vector component.
C             6. P2 slowness-vector component.
C             7. P3 slowness-vector component.
C             8. Real part of ray amplitude, normalized to 1 at an
C                initial surface or along on a unit sphere around a
C                point source, corresponding to P- or S1-polarization at
C                the initial point of the ray.
C             9. Imaginary part of ray amplitude corresponding to P- or
C                S1-polarization at the initial point of the ray.
C                Printed only if greater than 0.000001 in abs value.
C            10. Real part of ray amplitude corresponding to
C                S2-polarization at the initial point of the ray.
C                Printed only if greater than 0.000001 in abs value.
C            11. Imaginary part of ray amplitude corresponding
C                S2-polarization at the initial point of the ray.
C                Printed only if greater than 0.000001 in abs value.
C             Default: NQ=4
C     KALL=integer:
C             KALL.LE.0: only two-point rays are considered,
C             KALL.GE.1: all rays are considered.
C             Absolute value specifies the form of the strings
C             describing individual points.  Here are some examples:
C             ABS(KALL)=0: 'rec   13'
C                          'recnam'
C                          'srcnam TO recnam'
C             ABS(KALL)=1: 'RAY  112'
C                          'RAY  112, REC   13'
C                          'RAY  112 TO recnam'
C                          'RAY  112 FROM srcnam'
C                          'RAY  112 FROM srcnam TO recnam'
C             ABS(KALL)=2: 'WAVE   1, RAY  112'
C                          'WAVE   1, RAY  112, REC   13'
C                          'WAVE   1, RAY  112 TO recnam'
C                          'WAVE   1, RAY  112 FROM srcnam'
C                          'WAVE   1, RAY  112 FROM srcnam TO recnam'
C             Values KALL=0 and KALL=1 specify the briefest strings.
C             Default: KALL=0
C     KSRC=integer... Modification of the initial point of the ray.
C             0: No modification of the initial point of the ray.
C             1: If the sourcer file is specified, the coordinates of
C                the initial point of a ray are replaced by the source
C                coordinates and the travel time is linearly
C                interpolated from the initial point to the source
C                point.
C             Default: KSRC=0
C     KTWO=integer... Converting initial-value to two-point travel time.
C             0: No modification of the initial-value travel time.
C             1: The initial-value travel time is replaced by the
C                two-point travel time.
C                The two-point travel time is the initial-value travel
C                time minus the travel time at the initial point of the
C                ray.
C             Default: KTWO=0
C Optional parameters specifying the form of the real quantities
C written in the output formatted files:
C     MINDIG,MAXDIG=positive integers ... See the description in file
C             
C             forms.for.
C
C                                                    
C Output formatted file RAYS (format LIN):
C (1) / (a slash).
C (2) For each ray (2.1), (2.2), and (2.3):
C (2.1) 'RAYTXT',/
C     'RAYTXT'... String in apostrophes describing the ray.  See the
C             description of input parameter KALL.
C     /...    An obligatory slash after the string, in place of the
C             coordinates of the reference point.
C (2.2) For each point of the ray (2.1.1):
C (2.2.1) (OUT(I),I=1,NQ),/
C     (OUT(I),I=1,NQ)... Output quantities at the ray point, see the
C             description of input parameter NQ.
C     /...    An obligatory slash after at the end of line, in place
C             where the slowness vector components could be written.
C     For default NQ=4:
C     (2.2.1) X1,X2,X3,TT,/
C     X1,X2,X3... Coordinates of the point of the ray.
C     TT...   Arrival time at the point.
C (2.3) / (a slash).
C (3) / (a slash).
C Description of format LIN
C
C-----------------------------------------------------------------------
C
C Common block /POINTC/ to store the results of complete ray tracing:
      INCLUDE 'pointc.inc'
C     pointc.inc
C None of the storage locations of the common block are altered.
C
C Subroutines and external functions required:
      EXTERNAL CRTOUT,FORM2
C     CRTOUT..File 'crtout.for'.
C     AP00... File 'ap.for' (called by CRTOUT).
C     FORM2...File 'forms.for'.
C     FORM1...File 'forms.for' (called by FORM2).
C
C-----------------------------------------------------------------------
C
      CHARACTER*80 FILSEP,FCRT,CH
      INTEGER LU0
      PARAMETER (LU0=1)
C
C     Auxiliary storage locations:
      INTEGER LU1,LU2,LU3,MQ,MPTS,MOUT
      PARAMETER (LU1=1,LU2=2,LU3=3)
      PARAMETER (MQ=11,MPTS=2,MOUT=MQ*MPTS)
C     1:X1, 2:X2, 3:X3, 4:TT
C     Optional:           5:P1, 6:P2, 7:P3, 8:AR1, 9:AI1, 10:AR2, 11:AI2
      CHARACTER*80 FILE1,FILE2,FILE3,FILSRC,FILREC
      CHARACTER*(2+8*MQ) FORMAT
      CHARACTER*80 RAYTXT
      INTEGER NQ,KALL,NPTS,LENTXT,IQ
      REAL OUT(MOUT),OUTMIN(MQ),OUTMAX(MQ)
C
C-----------------------------------------------------------------------
C
C     Reading name of SEP file with input data:
      WRITE(*,'(A)') '+CRTRAY: Enter input filename: '
      FILSEP=' '
      READ(*,*) FILSEP
      WRITE(*,'(A)') '+CRTRAY: Working ...           '
C
C     Reading all data from the SEP file into the memory:
      IF (FILSEP.NE.' ') THEN
        CALL RSEP1(LU0,FILSEP)
      ELSE
C       CRTRAY-01
        CALL ERROR('CRTRAY-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('CRTOUT',FCRT,' ')
      FILE1='r01.out'
      FILE2='r01i.out'
      IF (FCRT.NE.' ') THEN
        OPEN (LU1,FILE=FCRT,FORM='FORMATTED',STATUS='OLD')
        READ (LU1,*) FILE1,CH,FILE2,CH
        CLOSE (LU1)
      ENDIF
      CALL RSEP3T('REC',FILREC,' ')
      CALL RSEP3T('SRC',FILSRC,' ')
      CALL RSEP3T('RAYS',FILE3,'rays.out')
C
C     Number of output quantities:
      CALL RSEP3I('NQ',NQ,4)
C     Switch between all rays and only two-point rays:
      CALL RSEP3I('KALL',KALL,0)
C
      NQ=MIN0(NQ,MQ)
      CALL TXT1(LU3,FILSRC,FILREC)
      OPEN(LU1,FILE=FILE1,FORM='UNFORMATTED',STATUS='OLD')
      OPEN(LU2,FILE=FILE2,FORM='UNFORMATTED',STATUS='OLD')
      OPEN(LU3,FILE=FILE3)
C
C.......................................................................
C
C     Loop for the points of rays
   10 CONTINUE
C       Reading the results of the complete ray tracing
        NPTS=0
        CALL CRTOUT(LU1,LU2,KALL,0,1,MQ,MPTS,NPTS,OUT,OUTMIN,OUTMAX)
        IF(IWAVE.LT.1)THEN
C         End of rays
          GO TO 80
        END IF
C       Writing the results of the complete ray tracing
        FORMAT(1:1)='('
        CALL FORM2(NQ,OUTMIN,OUTMAX,FORMAT(2:2+8*NQ))
        IF(IPT.LE.1)THEN
C         New ray - recording the initial point
          CALL TXT2(KALL,0,ISRC,IWAVE,IRAY,IREC,LENTXT,RAYTXT)
          WRITE(LU3,'(A)') '/'
          WRITE(LU3,'(2A)') RAYTXT(1:LENTXT),' /'
          WRITE(LU3,FORMAT) OUT(1),(' ',OUT(IQ),IQ=2,NQ),' /'
        END IF
        WRITE(LU3,FORMAT) OUT(1+MQ*(NPTS-1)),
     *        (' ',OUT(IQ),IQ=2+MQ*(NPTS-1),MQ*(NPTS-1)+NQ),' /'
      GO TO 10
C
   80 CONTINUE
      WRITE(LU3,'(A)') '/'
      WRITE(LU3,'(A)') '/'
      CLOSE(LU3)
      CLOSE(LU2)
      CLOSE(LU1)
      WRITE(*,'(A)') '+CRTRAY: 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
      INCLUDE 'ap.for'
C     ap.for
      INCLUDE 'crtout.for'
C     crtout.for
C
C=======================================================================
C