Passing anonymous function to method

Question

testcalss.m:

classdef testclass
    properties(Access = public)
        a;
        F;
    end
    methods(Access = public)
        function this = testclass()            
            if (1 == 1)
                this.F = eval('@(x)a * x');
                eval('this.a = 5');
            end
        end
        function Calculate(this)
            a = this.a;
            this.F(1);
        end
    end
end

test1.m:

global solver;
solver = testclass();
solver.Calculate();

I execute test and after it I get such message:

Undefined function or variable 'a'. Error in testclass/testclass/@(x)ax Error in testclass/Calculate (line 18) this.F(1); Error in test1 (line 3) solver.Calculate();*

Did you write a Constructor? Are you sure the `this` syntax works on MATLAB? — BillBokeey, Nov 26 '15 at 15:34
Yes, this syntax works. There is a Constructor. You can do it such: `global solver; a = solver.a; b = solver.b; c = solver.c`. Before it, when I create my class, I write a line `global solver; solver = Parabolic();`. — hedgehogues, Nov 26 '15 at 15:37
Can you edit that into your question? And also, could provide something runnable? — lhcgeneva, Nov 26 '15 at 17:11

score 1 · Accepted Answer · edited May 23 '17 at 12:15

This is a problem related to the workspace the anonymous function is using. Also refer to here. This should work:

 classdef testclass
    properties(Access = public)
        a;
        F;
    end
    methods(Access = public)
        function this = testclass()            
            if (1 == 1)
                this.F = '@(x)a * x';
                this.a = 5;
            end
        end
        function Calculate(this)
            a = this.a;
            f = eval(this.F);
            f(1)
        end
    end
end

Essentially you locally make a new anonymous function using eval, because you can't pass anonymous functions with fix parameters (like a) around like this, at least as far as I am aware of.

Passing anonymous function to method

1 Answers1