Memory preallocation for array of objects with irregular array length property

Hi,

I have an array of objects from a class (let's say MyClass) and each object has as property an array of different length for each object. For example: MyClass_object(1).MyArray is 100x1 and MyClass_object(2).MyArray is 200x1.

Code for my class:

classdef MyClass < handle

    properties
        MyArray
    end

    methods
        function obj = MyClass(array_length)
            obj.MyArray = zeros(array_length,1);
        end


    end
end

Memory preallocation:

lengths = [100;200]
MyClass_object(1,:) = MyClass(lengths(1));
MyClass_object(2,:) = MyClass(lengths(2));

My question is: how is it possible to preallocate memory both for the objects and the arrays without coding one by one?

I tried this:

lengths = [100;200];

for i=1:length(lengths)
    MyClass_object(i,:) = MyClass(lengths(i));
end

But then I get an warning: Variable appears to change in size in every loop iteration.

Note: vector "lengths" might have 50 or more values.

Thanks!

[James Tursa]

Please show a small example class and explain what problems you are having with setting properties of different objects to different sizes.

[Stergios]

Hi James,

I have just edited it.

Stergios

Answer 1

[Walter Roberson]

Provided that MyClass_Object does not already exist:

lengths = [100;200];
NumL = length(lengths);

MyClass_Object(NumL, :) = MyClass(lengths(end));

for i=1:NumL-1
    MyClass_object(i,:) = MyClass(lengths(i));
end

[Stergios]

Hi Walter

Most probably you mean this:

MyClass_object(1:NumL, :) = MyClass(lengths(end));

instead of

MyClass_Object(NumL, :) = MyClass(lengths(end));

right?