Table of contents
CSPICE_UNLOAD unloads a SPICE kernel file (of any type)
from MATLAB.
Given:
file the name of the file(s) to unload.
[n,c1] = size(file); char = class(file)
or
[1,n] = size(file); cell = class(file)
This file should be one loaded through the interface
cspice_furnsh. If the file is not on the list of loaded
kernels no action is taken.
Note that if `file' is a meta-text kernel, all of
the files loaded as a result of loading the meta-text
kernel will be unloaded.
the call:
cspice_unload( file )
returns:
None.
It removes the file and all associated data from the kernel
sub-system. If `file' is a meta-text kernel, the sub-system
unloads all files listed in the kernel.
Note: a cspice_unload call deletes ALL kernel variables except
those loaded into the kernel pool via a cspice_furnsh kernel
load call, i.e. cspice_unload erases kernel variables placed
in the pool by the pool functions: cspice_pipool, cspice_pdpool,
and cspice_pcpool.
None.
Any numerical results shown for these examples may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
1) Load a PCK in the kernel pool and look up the kernel variable
BODY399_RADII, then unload the kernel and look the variable up
again. In the later case, the POOL subsystem shall throw
an error indicating that the kernel POOL variable does
not exist.
Use the PCK kernel below to load the required triaxial
ellipsoidal shape model for the Earth, which uses the kernel
variable BODY399_RADII to store the Earth's radii data.
pck00010.tpc
Example code begins here.
function unload_ex1()
%
% Load a PCK kernel.
%
cspice_furnsh( 'pck00010.tpc' )
%
% When the kernel variable
%
% BODY399_RADII
%
% is present in the kernel pool---normally because a PCK
% defining this variable has been loaded (as is the case
% here)---the call
%
disp( 'Calling cspice_bodvrd after loading the PCK:' )
try
values = cspice_bodvrd( 'EARTH', 'RADII', 3);
disp(' Expected result, found kernel data')
catch
disp(' ERROR: Unexpected result, no kernel data found')
end
%
% Now unload the kernel and try again.
%
cspice_unload( 'pck00010.tpc' )
disp( 'Calling cspice_bodvrd after unloading the PCK:' )
try
values = cspice_bodvrd( 'EARTH', 'RADII', 3);
disp(' ERROR: Unexpected result, found kernel data')
catch
disp(' Expected result, no kernel data found')
end
When this program was executed on a Mac/Intel/Octave6.x/64-bit
platform, the output was:
Calling cspice_bodvrd after loading the PCK:
Expected result, found kernel data
Calling cspice_bodvrd after unloading the PCK:
Expected result, no kernel data found
2) Load a meta-kernel with a PCK, an LSK and an SPK, and
separately a text kernel and a binary PCK. Loop over the
loaded kernels, outputting file information for each of
them.
Then unload the text kernels, check that they have been
unloaded, and finally unload the meta-kernel.
Use the meta-kernel shown below to load the required SPICE
kernels.
KPL/MK
File name: unload_ex2.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
pck00009.tpc Planet orientation and
radii
naif0012.tls Leapseconds
\begindata
KERNELS_TO_LOAD = ( 'de421.bsp',
'naif0012.tls',
'pck00009.tpc' )
\begintext
End of meta-kernel
Use the PCK kernel below as the binary PCK required for the
example.
earth_latest_high_prec.bpc
Use the FK kernel below as the text kernel required for the
example.
RSSD0002.TF
Example code begins here.
function unload_ex2()
%
% Load several kernel files.
%
cspice_furnsh( 'unload_ex2.tm' );
cspice_furnsh( 'RSSD0002.TF' );
cspice_furnsh( 'earth_latest_high_prec.bpc' );
%
% Count the number of loaded kernel files.
%
[count] = cspice_ktotal( 'ALL' );
fprintf( [ 'The total number of kernels after final', ...
' cspice_furnsh: %1d\n' ], count )
fprintf( ' \n' )
%
% Unload the text kernels.
%
[count] = cspice_ktotal( 'TEXT' );
fprintf( ' \n' )
fprintf( 'Unloading %1d text kernels...\n', count )
fprintf( ' \n' )
while ( count != 0 )
[file, filtyp, srcfil, ...
handle, found] = cspice_kdata( 1, 'TEXT' );
%
% If the kernel is found in the pool, unload it.
%
if ( found )
cspice_unload( file );
%
% Check if the file has been unloaded.
%
[filtyp, srcfil, handle, found] = cspice_kinfo( file );
if ( found )
fprintf( ' Error' )
else
fprintf( ' Success' )
end
fprintf( ' unloading %s\n', file )
%
% Something is not working. Inform NAIF.
%
else
fprintf( [ ' ERROR: No kernel found but cspice_ktotal', ...
' returns %d\n' ], count )
end
%
% Check if we have more text kernels to unload from
% the kernel pool. Note that unloading a text kernel
% or meta-kernel implies that the kernel pool is
% cleared, and any kernel(s) that were not to be
% unloaded are re-loaded. Therefore the `count' value
% changes, and the indexing of the files within the
% kernel pool too.
%
[count] = cspice_ktotal( 'TEXT' );
end
[count] = cspice_ktotal( 'ALL' );
fprintf( ' \n' )
fprintf( [ 'The total number of kernels after cspice_unload', ...
' calls: %1d\n' ], count )
%
% Unload the meta-kernel and retrieve the number of loaded
% after the clear.
%
cspice_unload( 'unload_ex2.tm' );
[count] = cspice_ktotal( 'ALL' );
fprintf( ' \n' )
fprintf( [ 'The total number of kernels after final', ...
' cspice_unload: %1d\n' ], count )
%
% It's always good form to unload kernels after use,
% particularly in Matlab due to data persistence.
%
cspice_kclear
When this program was executed on a Mac/Intel/Octave6.x/64-bit
platform, the output was:
The total number of kernels after final cspice_furnsh: 6
Unloading 3 text kernels...
Success unloading naif0012.tls
Success unloading pck00009.tpc
Success unloading RSSD0002.TF
The total number of kernels after cspice_unload calls: 3
The total number of kernels after final cspice_unload: 1
3) Redo the previous example, using the cspice_unload capability
of unloading kernels by listing them in an array of strings.
Use the meta-kernel and kernels of Example 2.
Example code begins here.
function unload_ex3()
%
% Load several kernel files.
%
cspice_furnsh( 'unload_ex2.tm' );
cspice_furnsh( 'RSSD0002.TF' );
cspice_furnsh( 'earth_latest_high_prec.bpc' );
%
% Count the number of loaded kernel files.
%
[count] = cspice_ktotal( 'ALL' );
fprintf( [ 'The total number of kernels after final', ...
' cspice_furnsh: %1d\n' ], count )
fprintf( ' \n' )
%
% Unload the text kernels.
%
[count] = cspice_ktotal( 'TEXT' );
fprintf( ' \n' )
fprintf( 'Unloading %1d text kernels...\n', count )
fprintf( ' \n' )
%
% Create an empty array of strings, to hold the
% names of the kernels to unload.
%
kernels = cell(count,1);
for i = 1: count
[file, filtyp, srcfil, ...
handle, found] = cspice_kdata( i, 'TEXT' );
%
% If the kernel is found in the pool, add it to the array.
%
if ( found )
kernels(i) = file;
fprintf( ' %s will be unloaded.\n', file );
%
% Something is not working. Inform NAIF.
%
else
fprintf( ' ERROR: No kernel found with index %d\n', i )
end
end
%
% Unload the kernels present in the `kernels' variable, and
% retrieve the number of remaining loaded kernels.
%
cspice_unload( kernels );
[count] = cspice_ktotal( 'ALL' );
fprintf( ' \n' )
fprintf( [ 'The total number of kernels after cspice_unload', ...
' call : %1d\n' ], count )
%
% Unload the meta-kernel and retrieve the number of loaded
% after the clear.
%
cspice_unload( 'unload_ex2.tm' );
[count] = cspice_ktotal( 'ALL' );
fprintf( ' \n' )
fprintf( [ 'The total number of kernels after final', ...
' cspice_unload: %1d\n' ], count )
%
% It's always good form to unload kernels after use,
% particularly in Matlab due to data persistence.
%
cspice_kclear
When this program was executed on a Mac/Intel/Octave6.x/64-bit
platform, the output was:
The total number of kernels after final cspice_furnsh: 6
Unloading 3 text kernels...
naif0012.tls will be unloaded.
pck00009.tpc will be unloaded.
RSSD0002.TF will be unloaded.
The total number of kernels after cspice_unload call : 3
The total number of kernels after final cspice_unload: 1
The call
cspice_unload ( file );
has the effect of "erasing" the last previous call:
cspice_furnsh ( file );
This interface allows you to unload binary and text kernels.
Moreover, if you used a meta-text kernel to set up your
working environment, you can unload all of the kernels loaded
through the meta-kernel by unloading the meta-kernel.
Unloading Text Kernels or Meta-Kernels
--------------------------------------
Part of the action of unloading text (or meta-text kernels) is
clearing the kernel pool and re-loading any kernels that were not in
the specified set of kernels to unload. Since loading of text
kernels is not a very fast process, unloading text kernels takes
considerably longer than unloading binary kernels. Moreover, since
the kernel pool is cleared, any kernel pool variables you have set
from your program by using one of the interfaces cspice_pcpool,
cspice_pdpool, cspice_pipool, or cspice_lmpool will be removed from the
kernel pool. For this reason, if you plan to use this feature in your
program, together with one of the routines specified above, you will need
to take special precautions to make sure kernel pool variables required
by your program do not inadvertently disappear.
1) If the specified kernel is not on the list of loaded kernels
no action is taken.
2) If the input argument `file' is undefined, an error is
signaled by the Matlab error handling system.
3) If the input argument `file' is not of the expected type, or
it does not have the expected dimensions and size, an error is
signaled by the Mice interface.
None.
1) See the note regarding the unloading of Text and meta-text
Kernels.
MICE.REQ
KERNEL.REQ
PCK.REQ
None.
J. Diaz del Rio (ODC Space)
E.D. Wright (JPL)
-Mice Version 1.2.0, 24-AUG-2021 (EDW) (JDR)
Fixed bug in vectorized unloading of kernels.
Edited the header to comply with NAIF standard. Added
example's problem statement and a reference to the required PCK.
Extended the example's output and added the solution to the
section.
Added -Parameters, -Exceptions, -Files, -Restrictions,
-Literature_References and -Author_and_Institution sections, and
completed -Particulars section.
Eliminated use of "lasterror" in rethrow.
Removed reference to the function's corresponding CSPICE header from
-Required_Reading section.
-Mice Version 1.1.1, 13-FEB-2015 (EDW)
Edited -I/O section to conform to NAIF standard for Mice
documentation.
-Mice Version 1.1.0, 17-DEC-2008 (EDW)
Added zzmice_str call on input `file' to convert string cells to
character arrays if `file' has type string cells. Properly
identified `file' as a vectorizable string/character array.
-Mice Version 1.0.0, 22-NOV-2005 (EDW)
Unload a SPICE kernel
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