Calling an object's method that changes its property not doing what I want.

Hello

An object has property MNL_beta and method train(input, output) that I want the object to update its MNL_beta property. What is actually happening is :

>> p1

p1 = 

    predictor_bundle

    Properties:
      MNL_beta: []

    Methods

>> p1.train(input, output)

ans = 

    predictor_bundle

    Properties:
      MNL_beta: [3x1 double]

    Methods

>> p1

p1 = 

    predictor_bundle

    Properties:
      MNL_beta: []

    Methods

What has happened? The p1's value has not changed at all?!?

>> p1 = p1.train(input, output)

p1 = 

    predictor_bundle

    Properties:
      MNL_beta: [3x1 double]

    Methods

>> p1

p1 = 

    predictor_bundle

    Properties:  
      MNL_beta: [3x1 double]

    Methods

But using the second syntax, it's done what I wanted. How do I accomplish the result of the second method, while using the syntax of the first method?

Thank you

Answer 1

[Chirag Gupta]

This would stem from the difference between Value classes and handle classes. Its explained here: http://www.mathworks.com/help/techdoc/matlab_oop/brfylwk-1.html

[Evan]

And so how would I exactly solve the problem?

My classdef is written as such :

classdef predictor_bundle

properties

MNL_beta

end

method

function obj = train(obj, input, output)

function here

end

end

end

Answer 2

[Evan]

Hello,

Here is my classdef code. What modifications would I need to make to solve the problem?

classdef predictor_bundle

      properties 
          MNL_beta;
      end

      methods

          function obj = predictor_bundle()
          end

          function obj = train(obj, input, output)
            Function here. 
          end

      end
  end

[Chirag Gupta]

classdef predictor_bundle < handle

....

end

[Chirag Gupta]

http://www.mathworks.com/matlabcentral/answers/12056-matlab-oop-question