MATLAB: How to preallocate memory for a structure in MATLAB 7.6 (R2008a)

arraycreateMATLABmemorypreallocatestructstructs

I would like to know how to preallocate memory for a structure.

Best Answer

There is a way to preallocate memory for a structure in MATLAB 7.6 (R2008a) using the STRUCT and REPMAT commands.
EXAMPLE 1: A structure with two fields
s.field1
s.field2
field_names = {'field1','field2'}; % Cell with field names
empty_cells = repmat(cell(1),1,numel(field_names));
entries = {field_names{:} ; empty_cells{:}};
s = struct(entries{:});
EXAMPLE 2: A structure with a field with a subfield
s.field1.subfield
s = struct('field1',struct('subfield',cell(1)));
EXAMPLE 3: An array of structures
v(1).field1
...
v(100).field1
s = struct('field1',cell(1));
v = repmat(s,100,1);
Even though the data elements pointed to by the different fields in a structure are not stored contiguously, a benefit of preallocating structures is that you avoid the (possibly time-consuming) operation of dynamically growing the structure field header. Please refer to the following documentation page for more information:
http://www.mathworks.com/help/matlab/matlab_prog/memory-requirements-for-a-structure-array.html
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