MATLAB: For a class object with a property that is an array of class objects, how to find the element in that array with highest property value

classesfinding the maxoop

I have a class object, where one of the properties of the object is an array of objects of a different class. So ClassA has a property called 'population' which is an array of ClassB objects. ClassB has a property called 'fitness'. I want to find the element in the 'population' that has the highest fitness.

classdef ClassA < handle
     properties
        population ClassB
     end
      methods
        function obj = ClassA(target, popSize)
             n = 1;
                while n <= popSize                    
                    obj.population(n) = ClassB(target);
                    n = n + 1;
                end
        end
      end

       classdef ClassB < handle
          properties
              genes
              fitness 
          end
      end

The ClassA constructor works. I'm able to fill the array with ClassB objects, each of them having a unique value for ClassB.fitness. I've tried the max() function, as seen below:

      target = 'Hello!';
      popSize = 100;
      obj = Population(target,popSize);
      [M, I] = max(obj.population.fitness)

But, to no avail. Any suggestions on how to find the max fitness without using a loop?

Thank you!

Best Answer

Your

obj.population.fitness

line returns comma separated values, not an array. So just enclose it in brackets:

[M, I] = max([obj.population.fitness])

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MATLAB: Is calling a superclass constructor after a use of the object not allowed

I can only speculate as to why it would not be allowed, but I assume there are hazards in using an object that is not finished being constructed...like feeding a baby that is only half way through being born, or driving a car that’s only half assembled.

Below is how I would re-implement. In your original design, it doesn't make sense to me that the classB constructor should have to set x if it has already been set in classA.

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classdef subclass < classA & classB
    
    %% METHODS
    methods
        % Constructor
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MATLAB: Notify event in a class

You are very close to having it working! In your Notify callback, you make a call to the constructor ClassA rather than a specifieid object of type ClassA. So you would give the argument to the ClassB constructor to pass an object of type ClassA and then reference that object instead of the class constructor:

classdef ClassB < handle
    properties
        button
    end
    methods
        function o = ClassB(classAObj)
            fig = figure;
            o.button = uicontrol(fig,'Style','pushbutton','Callback',@(~,~,~) notify(classAObj,'EventA'));
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Best Answer

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MATLAB: Is calling a superclass constructor after a use of the object not allowed

MATLAB: Notify event in a class

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