MATLAB: How to implement derived function

Question

Hello, I have the following simple code. The abstract class DistributionBase declares a probability distribution, and the derived class UniformDistribution implements uniform distribution on [0,1]. The following code (from the command line) produces an error:

UDF = UniformDistribution (); d = UDF.distributionFunction(3); Error using UniformDistribution/distributionFunction Too many input arguments.

The code for the two classes is below.

Thanks in advance for help! Philipp

classdef (Abstract) DistributionBase methods (Abstract = true) d = density(theta) d = distributionFunction(theta) end end

…

classdef UniformDistribution < DistributionBase

    methods
        function d = density(theta)
            if(theta < 0 || theta > 1)
                d = 0;
                return;
            else
                d = 1;
            end
        end
        function d = distributionFunction(theta)
            if(theta < 0)
                d = 0;
                return;
            elseif(theta > 1)
                d = 1;
                return;
            else
                d = theta;
                return;
            end
        end
    end

end

Answer 1

You missed obj in distributionFunction( obj, theta). Try

    >> udf = UniformDistribution;
    >> d = udf.distributionFunction(3)
    d =
         1

where

    classdef    UniformDistribution  
        methods
            function d = density( obj, theta)
                if(theta < 0 || theta > 1)
                    d = 0;
                else
                    d = 1;
                end
            end
            function d = distributionFunction( obj, theta)
                if(theta < 0)
                    d = 0;
                elseif(theta > 1)
                    d = 1;
                else
                    d = theta;
                end
            end
        end
    end