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v_handle, sdthdf

• sdthdf

Purpose

Class constructor for variable handle objects.

Description

The Structural Dynamics Toolbox supports variable handle objects, which act as pointers to variables that are actually stored as global variables, user data of graphical objects, or in files.

v_handle objects are used to

• allow context dependent reference to a single MATLAB variable
• provide a graphic callback when modifying the object in a function or the command line.

v_handle objects essentially behave like global variables with the notable exception that a clear command only deletes the handle and not the pointed data.

Only advanced programmers should really need access to the internal structure of v_handle.

sdthdf

The sdthdf is an internal function that implements the v_handle pointing when variables are stored in files. Some supported file formats are MATLAB 6 .mat files, MATLAB >7.3 HDF based .mat files, NASTRAN .op2, ABAQUS .fil ...

Here is an example of offload to HDF5 based mat files.

fname=fullfile(sdtdef('tempdir'),'ubeam_Stack_SE.mat');
fname2=fullfile(sdtdef('tempdir'),'ubeam_model.mat');
model=demosdt('demoubeam');cf=feplot;
cf.mdl=fe_case(cf.mdl,'assemble mk NoT -SE');
cf.Stack{'curve','defR'}=fe_eig(cf.mdl,[5 50 1e3]);

% save(off-load) some stack entries to a file
sdthdf('hdfmodelsave',fname,cf,'Stack_curve_defR')
% save model but not the off-loaded entries
fecom('save',fname2);

cf=fecom('load',fname2); % reload the model
sdthdf('hdfmodel',fname,cf); % reload pointers to the entries
cf.Stack{'defR'}

For MATLAB >7.3 HDF based .mat files, you can open a v_handle pointer to a variable in the file using

fname=fullfile(sdtdef('tempdir'),'ubeam_Stack_SE.mat');
var=sdthdf('hdfreadref -level0',fname,'Stack_curve_defR')

See also

SDT handle