C 
C Program 'srp.for' (Source and Receiver Points, or SuRface Points) to
C generate files containing source and/or receiver points corresponding
C to given configuration parameter(s).
C
C The dependence of the source and receiver coordinates on the
C configuration parameters is assumed to be linear.
C
C Version: 5.20
C Date: 1998, October 20
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                                                    
C Description of the data files:
C
C The input data are read by the list directed input (free format), the
C output data are designed for the list directed input.
C In the description of data files, each numbered paragraph indicates
C the beginning of a new input operation (new READ statement) or a new
C output line.
C If the symbolic name of the input variable is enclosed in apostrophes,
C the corresponding value in input data is of the type CHARACTER, i.e.
C it should be a character string enclosed in apostrophes.  If the first
C letter of the symbolic name is I-N, the corresponding value is of the
C type INTEGER.  Otherwise, the input parameter is of the type REAL and
C may or may not contain a decimal point.  Where indicated, a slash /
C should be placed after the last specified value, at the same line, to
C facilitate future extensions.
C
C Input data read from the * external unit:
C     The interactive * external unit may also be redirected to the file
C     containing the relevant data.
C (1) 'SRP','CNAME',C1,C2,/
C     'SRP'...Name of the input file specifying the unshifted points
C             corresponding to zero configuration parameters, and the
C             derivatives of their positions with respect to the
C             configuration parameters.
C     'CNAME'... Character string which is, without trailing blanks,
C             prefixed to the name of each unshifted point in order to
C             create the name of the corresponding point shifted
C             according to the configuration parameters C1,C2.
C     C1,C2...Configuration parameters describing new, shifted positions
C             of the given surface points (source, receivers, etc.).
C     Default: 'SRP'='srp.dat', 'CNAME'=' ', C1=0., C2=0.
C
C                                                     
C Input file 'SRP' with the unshifted points:
C (1) 'PTS1','PTS2','PTS3',...,/
C     One to MFILE=20 filenames terminated by a slash.  Names of the
C     output files with the shifted surface points, corresponding to
C     given configuration parameters C1,C2.  It is thus assumed, that
C     the shifted points are written to the same files for all values
C     of the configuration parameters.
C (2) For each filename, data (2.1) and (2.2):
C (2.1) For each point to be written to the output file data (2.1.1):
C (2.1.1) 'NAME',X10,X20,X30,X11,X21,X31,X12,X22,X32,/
C     'NAME'..Name of the unshifted point.  It will be appended to given
C             string 'CNAME' (with trailing blanks removed from both
C             'CNAME' and 'NAME') to form the name of the corresponding
C             shifted point.  The resulting composed name 'CNAMENAME' is
C             truncated to 80 characters.  However, some other
C             applications may truncate the names of points to 12, 11,
C             8, or even 6 characters.
C      X10,X20,X30... Coordinates of the unshifted points.
C      X11,X21,X31... Derivatives of the coordinates with respect to the
C             first configuration parameter C1.
C      X12,X22,X32... Derivatives of the coordinates with respect to the
C             second configuration parameter C2.
C      Default: X10=0., X20=0., X30=0., X11=0., X21=0., X31=0., X12=0.,
C             X22=0., X32=0.
C (2.2) /
C
C                                                     
C Output files PTS with the shifted surface points:
C (1) /
C (2) For each shifted point data (2.1):
C (2.1) 'CNAMENAME',X1,X2,X3,/
C     'CNAMENAME'..Name of the shifted point.
C      X1,X2,X3... Coordinates of the shifted point,
C                  X1=X10+X11*C1+X12*C2,
C                  X2=X20+X21*C1+X22*C2,
C                  X3=X30+X31*C1+X32*C2.
C (3) /
C
C.......................................................................
C
C Date: 1997, April 29
C Coded by Ludek Klimes
C
C-----------------------------------------------------------------------
C
      PROGRAM srp
C
C     Filenames:
      INTEGER MFILE
      PARAMETER (MFILE=20)
      CHARACTER*80 FILE0,FILE1(MFILE)
C
C     Logical unit numbers:
      INTEGER LU0,LU1
      PARAMETER (LU0=10)
      PARAMETER (LU1=11)
C
C     Data:
      CHARACTER*80 NAME
      CHARACTER*8 CNAME
      CHARACTER*28 FORMAT
      INTEGER I,J,L
      REAL X(3),X1,X2,X3,X10,X20,X30,X11,X21,X31,X12,X22,X32,C1,C2
      EQUIVALENCE (X(1),X1),(X(2),X2),(X(3),X3)
C
C     I,J...  Loop variables.
C     X1,X2,X3... Coordinates of a point.
C     X00,X10,X20,X01,X11,X21,X02,X12,X22... Projection matrix from
C             configuration parameters to coordinates of a point.
C     C1,C2.. Configuration parameters of a point.
C
C.......................................................................
C
C     Opening data files and reading the input data:
C
C     Main input data file read from the interactive device (*):
      WRITE(*,'(A)')
     *  ' Enter data filename, configuration name, and two parameters: '
      FILE0='srp.dat'
      CNAME=' '
      C1=0.
      C2=0.
      READ(*,*) FILE0,CNAME,C1,C2
C
      OPEN(LU0,FILE=FILE0,STATUS='OLD')
      DO 10 I=1,MFILE
        FILE1(I)='$'
   10 CONTINUE
      READ(LU0,*) (FILE1(I),I=1,MFILE)
C
      DO 11 L=LEN(CNAME),1,-1
        IF(CNAME(L:L).NE.' ') THEN
          GO TO 12
        END IF
   11 CONTINUE
   12 CONTINUE
      L=L+1
C
C     Loop over output surface-point files:
      DO 30 I=1,MFILE
        IF(FILE1(I).EQ.'$') THEN
          GO TO 90
        END IF
        OPEN(LU1,FILE=FILE1(I))
        WRITE(LU1,'(A)') '/'
   20   CONTINUE
          NAME=CNAME
          NAME(L:L)='$'
          X10=0.
          X20=0.
          X30=0.
          X11=0.
          X21=0.
          X31=0.
          X12=0.
          X22=0.
          X32=0.
          READ(LU0,*) NAME(L:80),X10,X20,X30,X11,X21,X31,X12,X22,X32
          IF(NAME(L:80).EQ.'$'
     *                  .AND.X10.EQ.0..AND.X20.EQ.0..AND.X30.EQ.0.
     *                  .AND.X11.EQ.0..AND.X21.EQ.0..AND.X31.EQ.0.
     *                  .AND.X12.EQ.0..AND.X22.EQ.0..AND.X32.EQ.0.) THEN
            GO TO 29
          END IF
          DO 21 J=LEN(NAME),2,-1
            IF(NAME(J:J).NE.' ') THEN
              GO TO 22
            END IF
   21     CONTINUE
   22     CONTINUE
          X1=X10+X11*C1+X12*C2
          X2=X20+X21*C1+X22*C2
          X3=X30+X31*C1+X32*C2
          FORMAT(1:4)='(3A,'
          CALL FORM2(3,X,X,FORMAT(5:28))
          WRITE(LU1,FORMAT) '''',NAME(1:J),''' ',X1,' ',X2,' ',X3,' /'
        GO TO 20
   29   CONTINUE
        WRITE(LU1,'(A)') '/'
        CLOSE(LU1)
   30 CONTINUE
C
   90 CONTINUE
      CLOSE(LU0)
      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