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Index Page spk14a_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

       spk14a_c ( SPK, add data to a type 14 segment )

       void spk14a_c ( SpiceInt           handle,
                       SpiceInt           ncsets,
                       ConstSpiceDouble   coeffs [],
                       ConstSpiceDouble   epochs []  )

#### Abstract

       Add data to a type 14 SPK segment associated with `handle'.

#### Required_Reading

       SPK

#### Keywords

       SPK

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       handle     I   The handle of an SPK file open for writing.
       ncsets     I   The number of coefficient sets and epochs.
       coeffs     I   The collection of coefficient sets.
       epochs     I   The epochs associated with the coefficient sets.

#### Detailed_Input

       handle      is the file handle of an SPK file that has been
                   opened for writing.

       ncsets      is the number of Chebyshev coefficient sets and epochs
                   to be stored in the segment.

       coeffs      is a time-ordered array of `ncsets' of Chebyshev polynomial
                   coefficients to be placed in the segment of the SPK file.
                   Each set has size SETSZ = 2 + 6*(CHBDEG+1), where CHBDEG
                   is the degree of the Chebyshev polynomials used to
                   represent the ephemeris information.

                   These sets are used to compute the state vector, which
                   consists of position components X, Y, Z and velocity
                   components dX/dt, dY/dt, dZ/dt, of a body relative to
                   a center of motion.

                   See the -Particulars section for details on how to store
                   the coefficient sets in the array.

       epochs      contains the initial epochs (ephemeris seconds past
                   J2000) corresponding to the Chebyshev coefficients in
                   `coeffs'. The I'th epoch is associated with the I'th
                   Chebyshev coefficient set. The epochs must form a
                   strictly increasing sequence.

#### Detailed_Output

       None. The ephemeris data is stored in a segment in the SPK file
       associated with `handle'.

       See the -Particulars section for details about the structure of a
       type 14 SPK segment.

#### Parameters

       None.

#### Exceptions

       1)  If the number of coefficient sets and epochs is not positive,
           the error SPICE(INVALIDARGUMENT) is signaled by a routine in
           the call tree of this routine.

#### Files

       None.

#### Particulars

       This routine adds data to a type 14 SPK segment that is associated
       with the input argument handle. The segment must have been started
       by a call to the routine spk14b_c, the routine which begins a type
       14 SPK segment.

       This routine is one of a set of three routines for creating and
       adding data to type 14 SPK segments. These routines are:

          spk14b_c: Begin a type 14 SPK segment. This routine must be
                     called before any data may be added to a type 14
                     segment.

          spk14a_c: Add data to a type 14 SPK segment. This routine may be
                     called any number of times after a call to spk14b_c to
                     add type 14 records to the SPK segment that was
                     started.

          spk14e_c: End a type 14 SPK segment. This routine is called to
                     make the type 14 segment a permanent addition to the
                     SPK file. Once this routine is called, no further type
                     14 records may be added to the segment. A new segment
                     must be started.

       A type 14 SPK segment consists of coefficient sets for fixed order
       Chebyshev polynomials over consecutive time intervals, where the
       time intervals need not all be of the same length. The Chebyshev
       polynomials represent the position, X, Y, and Z coordinates, and
       the velocities, dX/dt, dY/dt, and dZ/dt, of body relative to
       center.

       The ephemeris data supplied to the type 14 SPK writer is packed
       into an array as a sequence of logical records,

          -----------------------------------------------------
          | Record 1 | Record 2 | ... | Record N-1 | Record N |
          -----------------------------------------------------

       with each record has the following format.

             ------------------------------------------------
             |  The midpoint of the approximation interval  |
             ------------------------------------------------
             |  The radius of the approximation interval    |
             ------------------------------------------------
             |  chbdeg+1 coefficients for the X coordinate  |
             ------------------------------------------------
             |  chbdeg+1 coefficients for the Y coordinate  |
             ------------------------------------------------
             |  chbdeg+1 coefficients for the Z coordinate  |
             ------------------------------------------------
             |  chbdeg+1 coefficients for the X velocity    |
             ------------------------------------------------
             |  chbdeg+1 coefficients for the Y velocity    |
             ------------------------------------------------
             |  chbdeg+1 coefficients for the Z velocity    |
             ------------------------------------------------

#### Examples

       The numerical results shown for these examples 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 demonstrates how to create an SPK type 14 kernel
          containing only one segment, given a set of Chebyshev
          coefficients and their associated epochs.

          Example code begins here.

          /.
             Program spk14a_ex1
          ./
          #include "SpiceUsr.h"

          int main( )
          {

             /.
             Define the segment identifier parameters.
             ./
             #define SPK14        "spk14a_ex1.bsp"
             #define REF          "J2000"
             #define BODY         3
             #define CENTER       10
             #define CHBDEG       2
             #define NRECS        4
             #define RECSIZ     ( 2 + 6*(CHBDEG+1) )

             /.
             Local variables.
             ./
             SpiceChar          * ifname;
             SpiceChar          * segid;

             SpiceDouble          first;
             SpiceDouble          last;

             SpiceInt             handle;
             SpiceInt             ncomch;

             /.
             Define the epochs and coefficients.
             ./
             SpiceDouble          epochs [NRECS+1] = {
                            100.0, 200.0, 300.0, 400.0, 500.0 };

             SpiceDouble          recrds [NRECS][RECSIZ] = {
                                       {150.0, 50.0,
                                        1.0101, 1.0102, 1.0103,
                                        1.0201, 1.0202, 1.0203,
                                        1.0301, 1.0302, 1.0303,
                                        1.0401, 1.0402, 1.0403,
                                        1.0501, 1.0502, 1.0503,
                                        1.0601, 1.0602, 1.0603},
                                       {250.0, 50.0,
                                        2.0101, 2.0102, 2.0103,
                                        2.0201, 2.0202, 2.0203,
                                        2.0301, 2.0302, 2.0303,
                                        2.0401, 2.0402, 2.0403,
                                        2.0501, 2.0502, 2.0503,
                                        2.0601, 2.0602, 2.0603},
                                       {350.0, 50.0,
                                        3.0101, 3.0102, 3.0103,
                                        3.0201, 3.0202, 3.0203,
                                        3.0301, 3.0302, 3.0303,
                                        3.0401, 3.0402, 3.0403,
                                        3.0501, 3.0502, 3.0503,
                                        3.0601, 3.0602, 3.0603},
                                       {450.0, 50.0,
                                        4.0101, 4.0102, 4.0103,
                                        4.0201, 4.0202, 4.0203,
                                        4.0301, 4.0302, 4.0303,
                                        4.0401, 4.0402, 4.0403,
                                        4.0501, 4.0502, 4.0503,
                                        4.0601, 4.0602, 4.0603} };

             /.
             Set the start and end times of interval covered by
             segment.
             ./
             first = epochs[0];
             last  = epochs[NRECS];

             /.
             `ncomch' is the number of characters to reserve for the
             kernel's comment area. This example doesn't write
             comments, so set to zero.
             ./
             ncomch = 0;

             /.
             Internal file name and segment ID.
             ./
             ifname = "Type 14 SPK internal file name.";
             segid  = "SPK type 14 test segment";

             /.
             Open a new SPK file.
             ./
             spkopn_c ( SPK14, ifname, ncomch, &handle );

             /.
             Begin the segment.
             ./
             spk14b_c ( handle, segid, BODY, CENTER, REF, first, last, CHBDEG );

             /.
             Add the data to the segment all at once.
             ./
             spk14a_c ( handle, NRECS, recrds, epochs );

             /.
             End the segment, making the segment a permanent addition
             to the SPK file.
             ./
             spk14e_c ( handle );

             /.
             Close the SPK file.
             ./
             spkcls_c ( handle );

             return ( 0 );
          }

          When this program is executed, no output is presented on
          screen. After run completion, a new SPK type 14 exists in
          the output directory.

       2) This example demonstrates how to add type 14 SPK records to the
          segment being written, one at a time. The ability to write the
          records in this way is useful if computer memory is limited. It
          may also be convenient from a programming perspective to write
          the records this way.

          Example code begins here.

          /.
             Program spk14a_ex2
          ./
          #include "SpiceUsr.h"

          int main( )
          {

             /.
             Define the segment identifier parameters.
             ./
             #define SPK14        "spk14a_ex2.bsp"
             #define REF          "J2000"
             #define BODY         3
             #define CENTER       10
             #define CHBDEG       2
             #define NRECS        4
             #define RECSIZ     ( 2 + 6*(CHBDEG+1) )

             /.
             Local variables.
             ./
             SpiceChar          * ifname;
             SpiceChar          * segid;

             SpiceDouble          first;
             SpiceDouble          last;

             SpiceInt             handle;
             SpiceInt             i;
             SpiceInt             ncomch;

             /.
             Define the epochs and coefficients.
             ./
             SpiceDouble          epochs [NRECS+1] = {
                            100.0, 200.0, 300.0, 400.0, 500.0 };

             SpiceDouble          recrds [NRECS][RECSIZ] = {
                                       {150.0, 50.0,
                                        1.0101, 1.0102, 1.0103,
                                        1.0201, 1.0202, 1.0203,
                                        1.0301, 1.0302, 1.0303,
                                        1.0401, 1.0402, 1.0403,
                                        1.0501, 1.0502, 1.0503,
                                        1.0601, 1.0602, 1.0603},
                                       {250.0, 50.0,
                                        2.0101, 2.0102, 2.0103,
                                        2.0201, 2.0202, 2.0203,
                                        2.0301, 2.0302, 2.0303,
                                        2.0401, 2.0402, 2.0403,
                                        2.0501, 2.0502, 2.0503,
                                        2.0601, 2.0602, 2.0603},
                                       {350.0, 50.0,
                                        3.0101, 3.0102, 3.0103,
                                        3.0201, 3.0202, 3.0203,
                                        3.0301, 3.0302, 3.0303,
                                        3.0401, 3.0402, 3.0403,
                                        3.0501, 3.0502, 3.0503,
                                        3.0601, 3.0602, 3.0603},
                                       {450.0, 50.0,
                                        4.0101, 4.0102, 4.0103,
                                        4.0201, 4.0202, 4.0203,
                                        4.0301, 4.0302, 4.0303,
                                        4.0401, 4.0402, 4.0403,
                                        4.0501, 4.0502, 4.0503,
                                        4.0601, 4.0602, 4.0603} };

             /.
             Set the start and end times of interval covered by
             segment.
             ./
             first = epochs[0];
             last  = epochs[NRECS];

             /.
             `ncomch' is the number of characters to reserve for the
             kernel's comment area. This example doesn't write
             comments, so set to zero.
             ./
             ncomch = 0;

             /.
             Internal file name and segment ID.
             ./
             ifname = "Type 14 SPK internal file name.";
             segid  = "SPK type 14 test segment";

             /.
             Open a new SPK file.
             ./
             spkopn_c ( SPK14, ifname, ncomch, &handle );

             /.
             Begin the segment.
             ./
             spk14b_c ( handle, segid, BODY, CENTER, REF, first, last, CHBDEG );

             /.
             Write the records to the segment in the
             SPK file one at at time.
             ./
             for ( i = 0; i < NRECS; i++ )
             {
                spk14a_c ( handle, 1, recrds[i], epochs+i );
             }

             /.
             End the segment, making the segment a permanent addition
             to the SPK file.
             ./
             spk14e_c ( handle );

             /.
             Close the SPK file.
             ./
             spkcls_c ( handle );

             return ( 0 );
          }

          When this program is executed, no output is presented on
          screen. After run completion, a new SPK type 14 exists in
          the output directory.

#### Restrictions

       1)  The type 14 SPK segment to which we are adding data must have
           been started by the routine SPK14B, the routine which begins a
           type 14 SPK segment.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       K.R. Gehringer      (JPL)

#### Version

       -CSPICE Version 1.0.1, 27-AUG-2021 (JDR) (NJB)

           Updated header to comply with NAIF standard. Added complete examples
           code from existing fragments.

           Extended "coeffs" argument description to provide the size of the
           Chebyshev polynomials sets.

           Re-ordered header sections. Removed reference to other routines
           from -Abstract section (already in -Particulars).

       -CSPICE Version 1.0.0, 29-JUL-1999 (NJB) (KRG)

#### Index_Entries

       add data to a type_14 SPK segment

#### Link to routine spk14a_c source file spk14a_c.c

    Fri Dec 31 18:41:12 2021