Why properties of class is not initialized ?

classdef EKF
       
   properties
      is_initialized_ = false;

      previous_timestamp_ = 0;
      H_jacobian = zeros(3, 4);
      %measurement covariance matrix - laser
      R_laser_ = [0.0225, 0;
                  0, 0.0225];
    
      noise_ax;
      noise_ay;
   end
   
   methods
      function obj = EKF(obj)
       obj.noise_ax = 5;
       obj.H_laser_ = [1, 0, 0, 0;
          0, 1, 0, 0];
      end
      
   end
  
    
end 

When I create an object of this class, I just get back. WHy these properties are not initialized ?

> obj = EKF
  EKF with properties:

    Value: []

Answer 1

[Robert U]

Hi Hafiz Luqman

The class definition you posted is errornous. The property "H_laser_" is not defined. So the constructor returns error:

test = EKF
No public property H_laser_ exists for class EKF.

Error in EKF (line 19)
       obj.H_laser_ = [1, 0, 0, 0;
           

While programming oop and evaluating changes of code it happens that earlier class definitions remain in memory. You could try to use

       clear all     

The corrected class definition (without questioning the sense) is working without troubles and as expected:

classdef EKF
       
   properties
      is_initialized_ = false;
      previous_timestamp_ = 0;
      H_jacobian = zeros(3, 4);
      %measurement covariance matrix - laser
      R_laser_ = [0.0225, 0;
                  0, 0.0225];
    
      noise_ax;
      noise_ay;
      H_laser_;
   end
   
   methods
      function obj = EKF(~)
       obj.noise_ax = 5;
       obj.H_laser_ = [1, 0, 0, 0;
                       0, 1, 0, 0];
      end
      
   end
  
    
end 

Kind regards,

Robert