what is wrong of this class

 classdef dummya
    properties
        value;
    end
    methods
        function obj = dummya( aa)
            obj.value = test( aa);
        end
    end
    methods (Static)       
        function y = my_pi(a)
            y = 3.141592*test(a);
        end
    end
    methods 
        function y = test(a)
            y = 3.141592*a;
        end
    end    
end

Answer 1

[Jared]

What is the error you are receiving? I saved your test code to file (dummy.m) and it seemed to work.

[C Shen]

Sorry, Wrong question. I Changed it.

Error message is:

??? Undefined function or method 'test' for input arguments of type 'double'.

[Jared]

Ok, I think the key is static methods.

Most class methods require an object as an input. That is, you could write:

function = test(obj,a)

...

end

You can call the method either as test(obj,a) or as obj.test(a) for some obj.

The exception to this are static methods. From the help file:

"Static methods are associated with a class, but not with specific instances of that class. These methods do not perform operations on individual objects of a class and, therefore, do not require an instance of the class as an input argument, like ordinary methods."

Thus, my_pi(a) works just fine, even though a is not an instance of the class, dummya.

Does this make sense?

[C Shen]

But Static method can't call regular method, right?

classdef dummya

properties

value;

end

methods

function obj = dummya( aa)

obj.value = mtest(obj, aa);

obj.value = dummya.sfun(aa); %this does not work

end

end

methods (Static)

function obj = sfun(a)

obj = 2*mtest(obj,a);

end

end

methods

function y = mtest(obj, a)

y = 3*a;

end

end

end