Index Page dskb02_c

A B C D E F G H I J K L M N O P Q R S T U V W X

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

       void dskb02_c ( SpiceInt               handle,
                       ConstSpiceDLADescr   * dladsc,
                       SpiceInt             * nv,
                       SpiceInt             * np,
                       SpiceInt             * nvxtot,
                       SpiceDouble            vtxbds  [3][2],
                       SpiceDouble          * voxsiz,
                       SpiceDouble            voxori  [3],
                       SpiceInt               vgrext  [3],
                       SpiceInt             * cgscal,
                       SpiceInt             * vtxnpl,
                       SpiceInt             * voxnpt,
                       SpiceInt             * voxnpl          )

#### Abstract

       Return bookkeeping data from a DSK type 2 segment.

#### Required_Reading

       DAS
       DSK

#### Keywords

       DAS
       DSK
       FILES

#### Brief_I/O

       Variable  I/O  Description
       --------  ---  --------------------------------------------------
       handle     I   DSK file handle.
       dladsc     I   DLA descriptor.
       nv         O   Number of vertices in model.
       np         O   Number of plates in model.
       nvxtot     O   Number of voxels in fine grid.
       vtxbds     O   Vertex bounds.
       voxsiz     O   Fine voxel edge length.
       voxori     O   Fine voxel grid origin.
       vgrext     O   Fine voxel grid exent.
       cgscal     O   Coarse voxel grid scale.
       vtxnpl     O   Size of vertex-plate correspondence list.
       voxnpt     O   Size of voxel-plate pointer list.
       voxnpl     O   Size of voxel-plate correspondence list.

#### Detailed_Input

       handle         is the handle of a DSK file containing a type 2
                      segment from which data are to be fetched.

       dladsc         is the DLA descriptor associated with the segment
                      from which data are to be fetched.

#### Detailed_Output

       nv         Number of vertices in model.

       np         Number of plates in model.

       nvxtot     Total number of voxels in fine grid.

       vtxbds     Vertex bounds. This is an array of six values giving
                  the minimum and maximum values of each component of
                  the vertex set.  `vtxbds' has dimensions [3][2].
                  Units are km.

       voxsiz     Fine grid voxel size.  DSK voxels are cubes; the edge
                  length of each cube is given by the voxel size.  This
                  size applies to the fine voxel grid.  Units are km.

       voxori     Voxel grid origin.  This is the location of the voxel
                  grid origin in the body-fixed frame associated with
                  the target body.  Units are km.

       vgrext     Voxel grid extent.  This extent is an array of three
                  integers indicating the number of voxels in the X, Y, and
                  Z directions in the fine voxel grid.

       cgscal     Coarse voxel grid scale.  The extent of the fine voxel
                  grid is related to the extent of the coarse voxel grid by
                  this scale factor.

       vtxnpl     Vertex-plate correspondence list size.

       voxnpt     Size of the voxel-to-plate pointer list.

       voxnpl     Voxel-plate correspondence list size.

#### Parameters

       See the header files

          SpiceDLA.h
          SpiceDSK.h

#### Exceptions

       1) If the input handle is invalid, the error will be diagnosed by
          routines in the call tree of this routine.

       2) If a file read error occurs, the error will be diagnosed by
          routines in the call tree of this routine.

       3) If the input DLA descriptor is invalid, the effect of this
          routine is undefined. The error *may* be diagnosed by routines
          in the call tree of this routine, but there are no
          guarantees.

#### Files

       See input argument `handle'.

#### Particulars

       This routine supports computations involving bookkeeping information
       stored in DSK type 2 segments. User applications typically will not
       need to call this routine.

       DSK files are built using the DLA low-level format and the DAS
       architecture; DLA files are a specialized type of DAS file in which
       data are organized as a doubly linked list of segments.  Each
       segment's data belong to contiguous components of character, double
       precision, and integer type.

#### 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) Dump several parameters from the first DLA segment of
          a DSK file. The segment is assumed to be of type 2.

          Example code begins here.

             #include <stdio.h>
             #include "SpiceUsr.h"
             #include "SpiceDLA.h"
             #include "SpiceDSK.h"

             int main()
             {
                /.
                Constants
                ./
                #define FILSIZ          256

                /.
                Local variables
                ./
                SpiceBoolean            found;

                SpiceChar               dsk  [ FILSIZ ];

                SpiceDLADescr           dladsc;

                SpiceDouble             voxori [3];
                SpiceDouble             voxsiz;
                SpiceDouble             vtxbds [3][2];

                SpiceInt                cgscal;
                SpiceInt                handle;
                SpiceInt                np;
                SpiceInt                nv;
                SpiceInt                nvxtot;
                SpiceInt                vgrext [3];
                SpiceInt                voxnpl;
                SpiceInt                voxnpt;
                SpiceInt                vtxnpl;

                /.
                Prompt for the name of DSK to read.
                ./
                prompt_c ( "Enter DSK name > ", FILSIZ, dsk );

                /.
                Open the DSK file for read access. We use the
                DAS-level interface for this function.
                ./
                dasopr_c ( dsk, &handle );

                /.
                Begin a forward search through the kernel. In
                this example, it's a very short search.
                ./
                dlabfs_c ( handle, &dladsc, &found );

                if ( !found )
                {
                   setmsg_c ( "No segment found in file #." );
                   errch_c  ( "#",  dsk                     );
                   sigerr_c ( "SPICE(NOSEGMENT)"            );
                }

                /.
                If we made it this far, DLADSC is the
                DLA descriptor of the first segment.
                Read and display type 2 bookkeeping data.
                ./
                dskb02_c ( handle,  &dladsc, &nv,    &np,    &nvxtot,
                           vtxbds,  &voxsiz, voxori, vgrext, &cgscal,
                           &vtxnpl, &voxnpt, &voxnpl                 );

                printf ( "\n"
                         "Number of vertices:                 %d\n"
                         "Number of plates:                   %d\n"
                         "Number of voxels:                   %d\n"
                         "Vertex bounds in X direction (km):  %f : %f\n"
                         "Vertex bounds in Y direction (km):  %f : %f\n"
                         "Vertex bounds in Z direction (km):  %f : %f\n"
                         "Voxel edge length (km):             %f\n"
                         "Voxel grid origin (km):           ( %f %f %f )\n"
                         "Voxel grid extents:                 %d %d %d\n"
                         "Coarse voxel grid scale:            %d\n"
                         "Size of vertex-plate list:          %d\n"
                         "Size of voxel-plate pointer array:  %d\n"
                         "Size of voxel-plate list:           %d\n",
                         (int)nv,
                         (int)np,
                         (int)nvxtot,
                         vtxbds[0][0], vtxbds[0][1],
                         vtxbds[1][0], vtxbds[1][1],
                         vtxbds[2][0], vtxbds[2][1],
                         voxsiz,
                         voxori[0], voxori[1], voxori[2],
                         (int)vgrext[0], (int)vgrext[1], (int)vgrext[2],
                         (int)cgscal,
                         (int)vtxnpl,
                         (int)voxnpt,
                         (int)voxnpl                                       );
                /.
                Close the kernel.  This isn't necessary in a stand-
                alone program, but it's good practice in subroutines
                because it frees program and system resources.
                ./
                dascls_c ( handle );

                return ( 0 );
             }

       When this program was executed on a PC/Linux/gcc/64bit
       platform, using a DSK file representing a regular icosahedron,
       the output was:

          Number of vertices:                 12
          Number of plates:                   20
          Number of voxels:                   512
          Vertex bounds in X direction (km):  -1.051460 : 1.051460
          Vertex bounds in Y direction (km):  -1.000000 : 1.000000
          Vertex bounds in Z direction (km):  -1.175570 : 1.175570
          Voxel edge length (km):             0.901744
          Voxel grid origin (km):           ( -3.606976 -3.606976 -3.606976 )
          Voxel grid extents:                 8 8 8
          Coarse voxel grid scale:            2
          Size of vertex-plate list:          72
          Size of voxel-plate pointer array:  64
          Size of voxel-plate list:           288

#### Restrictions

       1) The caller must verify that the segment associated with
          the input DLA descriptor is a DSK type 2 segment.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman    (JPL)

#### Version

       -CSPICE Version 2.1.0, 11-JUL-2016 (NJB)

          Edit to example program to use "%d" with explicit casts
          to int for printing SpiceInts with printf.

          Removed unnecessary include statements. Updated
          header.

       -DSKLIB_C Version 2.0.1, 11-JUL-2014 (NJB)

          Added example program to header.

       -DSKLIB_C Version 2.0.0, 13-MAY-2010 (NJB)

          Updated for compatibility with new DSK type 2 design.
          Name has been changed from dskp02_c to dskb02_c.

       -DSKLIB_C Version 1.0.0, 11-FEB-2010 (NJB)

#### Index_Entries

       fetch parameters from a type 2 dsk segment

#### Link to routine dskb02_c source file dskb02_c.c

    Wed Apr  5 17:54:32 2017