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cspice_dafgda

Table of contents
Abstract
I/O
Parameters
Examples
Particulars
Exceptions
Files
Restrictions
Required_Reading
Literature_References
Author_and_Institution
Version
Index_Entries

Abstract


   CSPICE_DAFGDA reads the double precision data bounded by two addresses
   within a DAF.

I/O


   Given:

      handle   file handle referring to a DAF.

               [1,1] = size(handle); int32 = class(handle)

      baddr,
      eaddr    initial and final addresses of a contiguous set of double
               precision numbers within a DAF. Presumably, these make up
               all or part of a particular array.

               Note that DAF addresses begin at 1 as in the
               FORTRAN version of the SPICE Toolkit.

               [1,1] = size(baddr); int32 = class(baddr)
               [1,1] = size(eaddr); int32 = class(eaddr)

   the call:

      data = cspice_dafgda( handle, baddr, eaddr )

   returns:

      data   are the double precision data contained between
             the specified addresses within the specified file.

             'data' has length = end - begin + 1.

             [1,length] = size(data); double = class(data)

Parameters


   None.

Examples


   Any numerical results shown for this example may differ between
   platforms as the results depend on the SPICE kernels used as input
   and the machine specific arithmetic implementation.

   1) Open a type 8 SPK for read access, retrieve the data for
      the first segment and identify the beginning and end addresses,
      the number of data elements within, the size of the data array,
      and print the first two records.

      Use the SPK kernel below as input type 8 SPK file for the example.

         mer1_ls_040128_iau2000_v1.bsp

      Each segment contains only two records which provide the start
      and end position for the MER-1 rover landing site in the IAU_MARS
      frame. Since the landing site does not change over time, it is
      expected that both records are equal.


      Example code begins here.


      function dafgda_ex1()

         %
         % Open the type 8 SPK for read access then read the
         % data from the first segment.
         %
         handle = cspice_dafopr( 'mer1_ls_040128_iau2000_v1.bsp');

         %
         % Begin a forward search; find the first segment; read the
         % segment summary.
         %
         cspice_dafbfs( handle )
         found    = cspice_daffna;
         [dc, ic] = cspice_dafgs( 2, 6 );

         %
         % Retrieve the data begin and end addresses.
         %
         baddr = ic(5);
         eaddr = ic(6);

         fprintf( 'Beginning address       : %d\n', baddr )
         fprintf( 'Ending address          : %d\n', eaddr )
         fprintf( 'Number of data elements : %d\n', eaddr - baddr + 1 )

         %
         % Extract all data bounded by the begin and end addresses.
         %
         data = cspice_dafgda( handle, baddr, eaddr );

         %
         % Check `data'. It should contain 2 * 6 + 4 elements.
         %
         fprintf( 'Size of data array      :(%d,%d)\n', size(data) )

         %
         % Check the data. Each set of 6 element records should possess the
         % property:
         %
         %   record(6) = record(6)
         %        i            i-1
         %
         fprintf( 'The first and second states stored in the segment:\n' );
         fprintf( ' %9.3f ', data(1:6) )
         fprintf('\n')

         fprintf( ' %9.3f ', data(7:12) )
         fprintf('\n')

         %
         % SAFELY close the file
         %
         cspice_dafcls(handle)


      When this program was executed on a Mac/Intel/Octave6.x/64-bit
      platform, the output was:


      Beginning address       : 897
      Ending address          : 912
      Number of data elements : 16
      Size of data array      :(1,16)
      The first and second states stored in the segment:
        3376.422   -326.649   -115.392      0.000      0.000      0.000
        3376.422   -326.649   -115.392      0.000      0.000      0.000


Particulars


   The principal reason that DAFs are so easy to use is that
   the data in each DAF are considered to be one long contiguous
   set of double precision numbers. You can grab data from anywhere
   within a DAF without knowing (or caring) about the physical
   records in which they are stored.

Exceptions


   1)  If `baddr' is zero or negative, the error SPICE(DAFNEGADDR)
       is signaled by a routine in the call tree of this routine.

   2)  If baddr > eaddr, the error SPICE(DAFBEGGTEND) is signaled by a
       routine in the call tree of this routine.

   3)  If `handle' is invalid, an error is signaled by a routine in the
       call tree of this routine.

   4)  If the range of addresses covered between `baddr' and `eaddr'
       includes records that do not contain strictly double
       precision data, then the values returned in `data' are
       undefined. See the -Restrictions section below for details.

   5)  If any of the input arguments, `handle', `baddr' or `eaddr',
       is undefined, an error is signaled by the Matlab error
       handling system.

   6)  If any of the input arguments, `handle', `baddr' or `eaddr',
       is not of the expected type, or it does not have the expected
       dimensions and size, an error is signaled by the Mice
       interface.

Files


   None.

Restrictions


   1)  There are several types of records in a DAF. This routine
       is only to be used to read double precision data bounded
       between two DAF addresses. The range of addresses input
       may not cross data and summary record boundaries.

Required_Reading


   MICE.REQ
   DAF.REQ

Literature_References


   None.

Author_and_Institution


   J. Diaz del Rio     (ODC Space)
   E.D. Wright         (JPL)

Version


   -Mice Version 1.1.0, 13-AUG-2021 (EDW) (JDR)

       Edited -Examples section to comply with NAIF standard. Added
       example's problem statement and a reference to required SPK file.

       Added -Parameters, -Exceptions, -Files, -Restrictions,
       -Literature_References and -Author_and_Institution sections.

       Eliminated use of "lasterror" in rethrow.

       Removed reference to the function's corresponding CSPICE header from
       -Required_Reading section.

   -Mice Version 1.0.0, 17-JUL-2012 (EDW)

Index_Entries


   read data from DAF address


Fri Dec 31 18:44:23 2021