Automatically update class properties

Hey there,

I've got the following problem: I've got a class with two properties A and B, which dependent on other properties hmatrix and n_FFT. Here is a minimal example:

classdef example

properties

hmatrix

n_FFT

A

B

end

methods

function obj = example()

obj.B = 10.*2^6;

obj.hmatrix = [0,1];

obj.n_FFT = 2^6;

end

function obj = set.hmatrix(obj,value)

obj.hmatrix = value;

obj.A = value.*obj.B;

end

function obj = set.n_FFT(obj,value)

obj.n_FFT = value;

obj.B = 10.*value;

obj.A = obj.hmatrix.*obj.B;

end

end

end

The property B depends on n_FFT and the property A depends on hmatrix and n_FFT (default values in constructor help when initializing).

Due to performance issues, I only want to recompute B and especially the property A (its more complicated than shown here), if the variables hmatrix and n_FFT change. Otherwise, I could do this by simply writing some get methods for the variables.

This code above runs, but the code analyzer is complaining that set methods should not access other properties, due to load order issues.

Is there a clean, "proper" way to do this, where I do not use get methods? I looked into dependent and transient properties but could not figure out how to use them without writing get methods, which are called every time.

Thank you very much! I

Answer 1

[Matt J]

See this recent, related thread,

https://www.mathworks.com/matlabcentral/answers/1845488-set-methods-for-two-interdependent-properties-in-class-how-do-i-avoid-infinite-recursion?s_tid=srchtitle

[Simon Baeuerle]

Thank you for the link and for your reply! However, my problem is not an infinite recursion. The code analyzer tells me to not access other properties in a set method, which are not dependent. I can't see how this example helps me w.r.t. that concern. Do you have any suggestions. Sorry - I am a little bit lost here.

[Matt J]

classdef example
    
properties
    
   hmatrix_
   n_FFT_
   A_
   B_   
    
end
    
properties (Dependent)
   hmatrix
   n_FFT
   A
   B
end
methods
    function obj = example()
       obj.B       = 10.*2^6;
       obj.hmatrix = [0,1];
       obj.n_FFT   = 2^6;
    end
    function obj = set.hmatrix(obj,value)
          obj.hmatrix_ = value;
          obj.A_ = value.*obj.B_;
    end
   function obj = set.n_FFT(obj,value)
          obj.n_FFT_ = value;
          obj.B_     = 10.*value;
          obj.A_ = obj.hmatrix.*obj.B_; 
   end
end
end