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gfrepi_c

Table of contents
Procedure
Abstract
Required_Reading
Keywords
Brief_I/O
Detailed_Input
Detailed_Output
Parameters
Exceptions
Files
Particulars
Examples
Restrictions
Literature_References
Author_and_Institution
Version
Index_Entries

Procedure

   gfrepi_c ( GF, progress report initialization ) 

   void gfrepi_c ( SpiceCell        * window,
                   ConstSpiceChar   * begmss,
                   ConstSpiceChar   * endmss  )

Abstract

   Initialize a search progress report.

Required_Reading

   GF

Keywords

   SEARCH
   UTILITY


Brief_I/O

   VARIABLE  I/O  DESCRIPTION
   --------  ---  --------------------------------------------------
   MXBEGM     P   Maximum progress report message prefix length.
   MXENDM     P   Maximum progress report message suffix length.
   window     I   A window over which a job is to be performed.
   begmss     I   Beginning of the text portion of output message.
   endmss     I   End of the text portion of output message.

Detailed_Input

   window      is the name of a constraint window. This is the window
               associated with some root finding activity. It is
               used to determine how much total time is being searched
               in order to find the events of interest.

               `window' must be declared as a double precision SpiceCell.

               CSPICE provides the following macro, which declares and
               initializes the cell

                  SPICEDOUBLE_CELL        ( window, WINDOWSZ );

               where WINDOWSZ is the maximum capacity of `window'.

   begmss      is the beginning of the progress report message written
               to standard output by the GF subsystem. This output
               message has the form

                  begmss xxx.xx% endmss

               The total length of `begmss' must be less than MXBEGM
               characters. All characters of `begmss' must be printable.

               For example, the progress report message created by the
               CSPICE routine gfocce_c at the completion of a search is

                  Occultation/transit search 100.00% done.

               In this message, `begmss' is

                  "Occultation/transit search"

   endmss      is the last portion of the output message written to
               standard output by the GF subsystem.

               The total length of `endmss' must be less than MXENDM
               characters. All characters of `endmss' must be printable.

               In the progress report message created by gfocce_c at the
               completion of a search, `endmss' is

                  "done."

Detailed_Output

   None.

Parameters

   MXBEGM,
   MXENDM      are, respectively, the maximum lengths of the progress
               report message prefix and suffix.

               Normally CSPICE developers will not need to reference
               these parameters; these are discussed only to help
               explain the functionality of this routine.

               The values of these parameters are defined in the
               SPICELIB Fortran INCLUDE file

                  zzgf.inc

Exceptions

   1)  If `begmss' has length greater than MXBEGM characters, or if
       `endmss' has length greater than MXENDM characters, the error
       SPICE(MESSAGETOOLONG) is signaled by a routine in the call
       tree of this routine.

   2)  If either `begmss' or `endmss' contains non-printing characters,
       the error SPICE(NOTPRINTABLECHARS) is signaled by a routine in
       the call tree of this routine.

   3)  If any of the `begmss' or `endmss' input string pointers is
       null, the error SPICE(NULLPOINTER) is signaled.

   4)  If any of the `begmss' or `endmss' input strings has zero
       length, the error SPICE(EMPTYSTRING) is signaled.

   5)  If the `window' cell argument has a type other than
       SpiceDouble, the error SPICE(TYPEMISMATCH) is signaled.

Files

   None.

Particulars

   This is one of three GF progress reporting routines that cooperate
   in order to display a report via console I/O. These routines may
   be used by SPICE-based applications as inputs to mid-level GF
   search routines.

   Developers wishing to use their own GF progress reporting routines
   must design them with the same interfaces and should assign them the
   same progress reporting roles as those of these routines.

   The GF progress reporting API routines are written to simplify
   reporting of work (such as searching for a geometric event) over a
   particular window. This is an important feature for interactive
   programs that may "go away" from the user's control for a
   considerable length of time. It allows the user to see that
   something is still going on (although maybe not too quickly).

   The three routines constituting the GF progress reporting API
   are:

      gfrepi_c  is used to prepare the reporting mechanism for a search
                pass. It is used to store the confinement window and
                progress report message prefix and suffix, and to
                initialize parameters associated with the reporting of
                the job in progress.

      gfrepu_c  is used to notify the progress reporting system that
                a specified increment of work has been completed
                since the last call to gfrepu_c or gfrepi_c, whichever
                occurred most recently.

      gfrepf_c  is used to "finish" the reporting of work (set the
                completion value to 100%.

Examples

   The numerical results shown for this example may differ across
   platforms. The results depend on the SPICE kernels used as
   input, the compiler and supporting libraries, and the machine
   specific arithmetic implementation.

   1) This example shows how to call a mid-level GF search API that
      requires as input progress reporting routines.

      If custom progress reporting routines are available, they
      can replace gfrepi_c, gfrepu_c, and gfrepf_c in any GF API calls.

      The code example below is the first example in the header of
      gfocce_c.


      Conduct a search using default GF progress reporting
      and interrupt handling capabilities.

      The program will use console I/O to display a simple
      ASCII-based progress report.

      The program will trap keyboard interrupts (on most systems,
      generated by typing the "control C" key combination). This
      feature can be used in non-trivial applications to allow
      the application to continue after a search as been interrupted.

      The program will find occultations of the Sun by the Moon as seen
      from the center of the Earth over the month December, 2001.

      Use light time corrections to model apparent positions of Sun
      and Moon. Stellar aberration corrections are not specified
      because they don't affect occultation computations.

      We select a step size of 20 seconds, which implies we ignore
      occultation events lasting less than 20 seconds, if any exist.
      Given this step size and the length of the search interval, the
      user has time to interrupt the computation. In an interactive
      setting, the user might speed up the search by lengthening the
      step size or shortening the search interval, as long as these
      adjustments don't prevent the search from finding the correct
      solution.

      Use the meta-kernel shown below to load the required SPICE
      kernels.


         KPL/MK

         File name: gfrepi_ex1.tm

         This meta-kernel is intended to support operation of SPICE
         example programs. The kernels shown here should not be
         assumed to contain adequate or correct versions of data
         required by SPICE-based user applications.

         In order for an application to use this meta-kernel, the
         kernels referenced here must be present in the user's
         current working directory.

         The names and contents of the kernels referenced
         by this meta-kernel are as follows:

            File name                     Contents
            ---------                     --------
            de421.bsp                     Planetary ephemeris
            pck00008.tpc                  Planet orientation and
                                          radii
            naif0009.tls                  Leapseconds


         \begindata

            KERNELS_TO_LOAD = ( 'de421.bsp',
                                'pck00008.tpc',
                                'naif0009.tls'  )

         \begintext

         End of meta-kernel


      Example code begins here.


      /.
         Program gfrepi_ex1
      ./
      #include <stdio.h>
      #include "SpiceUsr.h"

      int main()
      {
         /.
         Constants
         ./
         #define  TIMFMT  "YYYY MON DD HR:MN:SC.###### ::TDB (TDB)"
         #define  CNVTOL  1.e-6
         #define  MAXWIN  200
         #define  TIMLEN  41

         /.
         Local variables
         ./
         SpiceBoolean            bail;
         SpiceBoolean            rpt;

         SpiceChar             * win0;
         SpiceChar             * win1;
         SpiceChar               begstr [ TIMLEN ];
         SpiceChar               endstr [ TIMLEN ];

         SPICEDOUBLE_CELL      ( cnfine, MAXWIN );
         SPICEDOUBLE_CELL      ( result, MAXWIN );

         SpiceDouble             et0;
         SpiceDouble             et1;
         SpiceDouble             left;
         SpiceDouble             right;

         SpiceInt                i;

         /.
         Load kernels.
         ./
         furnsh_c ( "gfrepi_ex1.tm" );

         /.
         Obtain the TDB time bounds of the confinement
         window, which is a single interval in this case.
         ./
         win0 = "2001 DEC 10 00:00:00 TDB";
         win1 = "2002 JAN 01 00:00:00 TDB";

         str2et_c ( win0, &et0 );
         str2et_c ( win1, &et1 );

         /.
         Insert the time bounds into the confinement
         window.
         ./
         wninsd_c ( et0, et1, &cnfine );

         /.
         Select a twenty-second step. We'll ignore any occultations
         lasting less than 20 seconds.
         ./
         gfsstp_c ( 20.0 );

         /.
         Turn on interrupt handling and progress reporting.
         ./
         bail = SPICETRUE;
         rpt  = SPICETRUE;

         /.
         Perform the search.
         ./
         gfocce_c ( "ANY",
                    "MOON",     "ellipsoid",  "IAU_MOON",
                    "SUN",      "ellipsoid",  "IAU_SUN",
                    "LT",       "EARTH",      CNVTOL,
                    gfstep_c,   gfrefn_c,     rpt,
                    gfrepi_c,   gfrepu_c,     gfrepf_c,
                    bail,       gfbail_c,     &cnfine,
                    &result                              );


         if ( gfbail_c() )
         {
            /.
            Clear the CSPICE interrupt indication. This is
            an essential step for programs that continue
            running after an interrupt; gfbail_c will
            continue to return SPICETRUE until this step
            has been performed.
            ./
            gfclrh_c();


            /.
            We've trapped an interrupt signal. In a realistic
            application, the program would continue operation
            from this point. In this simple example, we simply
            display a message and quit.
            ./
            printf ( "\nSearch was interrupted.\n\nThis message "
                     "was written after an interrupt signal\n"
                     "was trapped. By default, the program "
                     "would have terminated \nbefore this message "
                     "could be written.\n\n"                       );
         }
         else
         {

            if ( wncard_c(&result) == 0 )
            {
               printf ( "No occultation was found.\n" );
            }
            else
            {
               for ( i = 0;  i < wncard_c(&result);  i++ )
               {
                  /.
                  fetch and display each occultation interval.
                  ./
                  wnfetd_c ( &result, i, &left, &right );

                  timout_c ( left,  TIMFMT, TIMLEN, begstr );
                  timout_c ( right, TIMFMT, TIMLEN, endstr );

                  printf ( "Interval %d\n", (int)i );
                  printf ( "   Start time: %s\n", begstr );
                  printf ( "   Stop time:  %s\n", endstr );
               }
            }

         }

         return ( 0 );
      }


      When this program was executed on a Mac/Intel/cc/64-bit
      platform, the output was:


      Occultation/transit search 100.00% done.

      Interval 0
         Start time: 2001 DEC 14 20:10:14.195952  (TDB)
         Stop time:  2001 DEC 14 21:35:50.317994  (TDB)


      Note that the progress report has the format shown below:

         Occultation/transit search   6.02% done.

      The completion percentage was updated approximately once per
      second.

      When the program was interrupted at an arbitrary time,
      the output was:

         Occultation/transit search  13.63% done.
         Search was interrupted.

         This message was written after an interrupt signal
         was trapped. By default, the program would have terminated
         before this message could be written.

Restrictions

   None.

Literature_References

   None.

Author_and_Institution

   N.J. Bachman        (JPL)
   J. Diaz del Rio     (ODC Space)
   L.S. Elson          (JPL)
   W.L. Taber          (JPL)
   I.M. Underwood      (JPL)
   E.D. Wright         (JPL)

Version

   -CSPICE Version 1.0.1, 06-AUG-2021 (JDR)

       Edited the header to comply with NAIF standard. Added
       complete code example.

       Updated the description of "window" argument.

       Added entry #5 in -Exceptions section.

   -CSPICE Version 1.0.0, 28-FEB-2009 (NJB) (LSE) (WLT) (IMU) (EDW)

Index_Entries

   GF initialize a progress report
Fri Dec 31 18:41:07 2021