inherit some class properties with changed values for A-star algorithm

Hi I've been meaning to visit this A* algorithm and I'm stuck on the creating nodes part. I thought it would be a prefect oportunity to learn classdef but i'm not so sure its propper for this project.

What i've done: I've made a function that creates an array of randomly generated (x,y) positions for the nodes with obstacles making sure that non of the nodes gets cought inside or on them (still needs to prohibit double values).

What I'm trying to do: I'm trying to create a node class that can contain the properties of it's respective node aswell as the parent and children so that they might be used for simpler "cost evaluation" of the g-value and heuretic value kinda like:

classdef start < handle
    properties
        name = 'start'
        position = [0 0]
        g_value = 0
        h_value = 2.828
        f_value = 2.828
    end
end

classdef nodes < dynamicprops & handle
    properties 
        position = []
        child = '';
        parent = '';
    end
    properties (Access = private)
        baseref;
    end
    methods 
        function this = nodes(baseobject)
            this.baseref = baseobject;
            % take the propertynames from the old and put it in the new
            for propname = properties(baseobject)'
                metaprop = addprop(this,propname{1});
                ... take the value in the property "name" from start and put it in current parent
            function this = set.parent(this,varargin{:})
                 this.parent = varargin{:}; 
            end
            function varargout = get.parent(this)
                varargout{:} = this.baseref.name;
            end
            end
            % calculate the new g-values in a similar fasion as below
            % if possible can allways be done "outside" otherwise
        this.g_value = this.baseref.g_value + norm(this.position - this.baseref.position);

    end
end

So that when used it can store the variable name of it's parent and child

startpos = start 
% here A will get 'startpos' as a parent
A = nodes(startpos); A.position = [0 1];
% and B will get 'A' as parent
B = nodes(A); B.position =[1 0]

and if possible to extract property values of the parent or child

>> A.parent
A.parent = 
         startpos
>> B.parent
B.parent =
         A

>> A.g_value
A.g_value = 
            1
>> B.g_value
B.g_value = 
            2.414
          
    

I'm only intrested in inhereting the g_value of the parent and extracting the position and variable name of the child and parent.

Answer 1

[prabhat kumar sharma]

Hi Nicolas,

I understand that you are facing issue with updating the properties for parent and children, I have tried running your code and I find out that you can store the properties, You can go through the following code for reference.

classdef nodes < dynamicprops & handle
    properties 
        name = '';
        position = [];
        child = '';
        parent = '';
    end
    properties (Access = private)
        baseref;
    end
    methods 
        function this = nodes(baseobject)
            
            this.baseref = baseobject;
            this.baseref.name = inputname(1)
            
            % Take the property names from the old and put them in the new
            for propname = properties(baseobject)'
                if ~isprop(this, propname{1}) % Check if property is already defined
                    metaprop = addprop(this, propname{1});
                end
            end
        end
        
        function set.parent(this, value)
            this.parent = value;
  
        end
        function value = get.parent(this)
            value = this.baseref.name;
            
        end
        
        function value = get.child(this)
            value = class(this);
        end
        
        % Calculate the new g-values in a similar fashion as below
        % If possible, it can always be done "outside" otherwise
        function calculateGValue(this)
            this.g_value = this.baseref.g_value + norm(this.position - this.baseref.position);
        end
    end
end

I have used the function “inputname” to get the workspace variable name.

For more information on “inputname” you can refer the below documentation:

https://mathworks.com/help/releases/R2022a/matlab/ref/inputname.html

Here is the below code to check the “parent” and “g_value”.

% Create objects and set positions
startpos = start;
A = nodes(startpos); 
A.position = [0 1];
B = nodes(A); 
B.position = [1 0];

% Calculate g_values
A.calculateGValue();
B.calculateGValue();

% Access parent and g_value properties
a_parent = A.parent;
b_parent = B.parent;
A_g_value = A.g_value;
B_g_value = B.g_value; 

Regards,

Prabhat Sharma