To obtain the coefficient value matrix Transforma​tionStateD​elayMatrix for for a method of a class definition NewtonRateConverter

I have tried to defined a class definition

classdef (StrictDefaults)NewtonRateConverter< dsp.FarrowRateConverter &...
                                               dsp.internal.SupportScalarVarSize & ...
                                                dsp.internal.MultirateEngine &...    
                                                dsp.internal.FilterAnalysisMultirate 
%Constructor 
methods
         
       function obj = NewtonRateConverter(varargin)
            % Constructor for the NewtonRateConverter class
            setProperties(obj, nargin, varargin{:}, ...
                'InputSampleRate', ...
                'OutputSampleRate', ...
                'OutputRateTolerance', ...
                'PolynomialOrder');
        end
   end
    

basically it overrides the Farrow Rate Converter and introduce certain conversions over it .

Now for it two Transformation Delay Matrices Td1 and Td2 are required. Mathematically Td1

M is the Polynomial Order

So I created function file for Td1

function Td1 = compute_Td1(M)
    % Create a matrix of binomial coefficients
    [I, J] = ndgrid(1:M, 1:M);
    binomials = zeros(M, M);
    for i = 1:M
        binomials(i, 1:i) = arrayfun(@(ii, jj) nchoosek(ii-1, jj-1), I(i, 1:i), J(i, 1:i)); 
    end
    % Create a matrix for powers
    powers = ((- (M - 1) / 2) .^ (I - J)) .* (J <= I);
    % Element-wise multiplication to get Td1
    Td1 = binomials .* powers;
end

This I defined as a static method in NewtonRateConverter

>> compute_Td1(3)

ans =

1 0 0

-1 1 0

1 -2 1

>> compute_Td1(5)

ans =

1 0 0 0 0

-2 1 0 0 0

4 -4 1 0 0

-8 12 -6 1 0

16 -32 24 -8 1

I entered this as a function as a property and method in this class definition NewtonRateConverter

 properties
       TransformationDelayMatrix1
       PolynomialOrder
   end
 methods
       function computeTransformationDelayMatrix1(obj)
           % Access PolynomialOrder from superclass
           
           M = obj.PolynomialOrder;
            
           % Compute TransformationDelayMatrix1 using compute_Td1
           obj.TransformationDelayMatrix1 = compute_Td1(M);
        end
   end

When I tried to access this object TransformationDelayMatrix1

% Initialization
myNRC = NewtonRateConverter('InputSampleRate', 44100, 'OutputSampleRate', 48000, 'PolynomialOrder', 3);
myNRC.TransformationDelayMatrix1

In the command window it displays :

>> myNRC.TransformationDelayMatrix1

ans =

[]

Why is this an empty array shown please could you clear out this doubt ?Please could you debugg ?I have tried to defined a class definition

classdef (StrictDefaults)NewtonRateConverter< dsp.FarrowRateConverter &...
                                               dsp.internal.SupportScalarVarSize & ...
                                                dsp.internal.MultirateEngine &...    
                                                dsp.internal.FilterAnalysisMultirate 
%Constructor 
methods
         
       function obj = NewtonRateConverter(varargin)
            % Constructor for the NewtonRateConverter class
            setProperties(obj, nargin, varargin{:}, ...
                'InputSampleRate', ...
                'OutputSampleRate', ...
                'OutputRateTolerance', ...
                'PolynomialOrder');
        end
   end
    

basically it overrides the Farrow Rate Converter and introduce certain conversions over it .

Now for it two Transformation Delay Matrix Tz are required. Mathematically Tz

M is the Polynomial Order

So I created function file for Tz

function T_z = calculate_Tz(M)
    % Initialize the matrix T_z with zeros
    T_z = zeros(M, M);
    
    % Fill the matrix T_z using the given formula
    for i = 1:M
        for j = 1:i % j goes from 1 to i
            T_z(i, j) = nchoosek(i-1, j-1) * (-1)^(j+1);
        end
    end
end

This I defined as a static method in NewtonRateConverter

>> calculate_Tz(3)

ans =

1 0 0

1 -1 0

1 -2 1

I entered this as a function as a property and method in this class definition NewtonRateConverter

 properties
       TransformationStateDelayMatrix 
   end

   methods
       function computeTransformationStateDelayMatrix(obj)
            % Access PolynomialOrder from superclass
            M = obj.PolynomialOrder;
            
            % Compute TransformationStateDelayMatrix using calculate_Tz
            obj.TransformationStateDelayMatrix = calculate_Tz(M);
        end
   end

When I tried to access this object TransformationDelayMatrix1

% Initialization
myNRC = NewtonRateConverter('InputSampleRate', 44100, 'OutputSampleRate', 48000, 'PolynomialOrder', 3);
myNRC.TransformationDelayMatrix1

In the command window it displays :

>> myNRC.TransformationStateDelayMatrix

ans =

[]

Why is this an empty array shown please could you clear out this doubt ?Please could you debugg or suggest solution for the problem?

[Walter Roberson]

What is the difference between this and the previous https://www.mathworks.com/matlabcentral/answers/2165704-to-obtain-the-coefficient-value-matrix-transformationdelaymatrix1-for-for-a-method-of-a-class-def?s_tid=srchtitle ?

Answer 1

[Gayathri]

Hi @Rohitashya,

I understand that you are getting an empty array for "TransformationStateDelayMatrix". This is because the function for calculating the matrix is not invoked yet.

myNRC = NewtonRateConverter('InputSampleRate', 44100, 'OutputSampleRate', 48000, 'PolynomialOrder', 3);
myNRC.computeTransformationDelayMatrix1();
myNRC.TransformationDelayMatrix1

Now, we will be getting a non-empty array for "TransformationStateDelayMatrix1".

Also, there is no need to mention "PolynomialOrder" in the properties section as this is already inherited.