how to return a function handle to a nested function that computed the value of a polynomialin matlab

how to return a function handle to a nested function that computed the value of a polynomialin matlab

[Rik]

Have a read here and here. It will greatly improve your chances of getting an answer.

Answer 1

[Purvaja]

Hi @JAYANTHI SANKARALINGAMi,

To create a MATLAB function that returns a handle to a nested function, you can refer to following steps.

1. Function Declaration: Declare a function that accepts a vector containing the polynomial coefficients (in descending order of power).
2. Nested Function: Inside the function, declare a nested function to compute the polynomial’s value at any given x.
3. Returning the Handle: The outer function returns a handle to nested function using the '@' operator. This allows you to evaluate the polynomial later, even though nested function is defined within outside function.

% Declare outer function 
function fh = getManualPolynomialHandle(coeffs) 

    % Declare nested function 
    function y = evaluatePolynomial(x) 
        % Evaluate polynomial at x using coeffs 
    end 
    
    % Return a function handle to the nested function. 
    fh = @evaluatePolynomial; 
end 

p1 = getManualPolynomialHandle([2, -3, 5]); 
result1 = p1(4);  
disp(result1); 

For more clarification on the functions used, you can refer to the following resources,

1. Function Handles: https://www.mathworks.com/help/matlab/function-handles.html
2. Nested Functions: https://www.mathworks.com/help/matlab/matlab_prog/nested-functions.html

Or you can access release specific documentation using these commands in your MATLAB command window respectively:

web(fullfile(docroot, 'matlab/function-handles.html')) 
web(fullfile(docroot, 'matlab/matlab_prog/nested-functions.html')) 

Hope this helps you!

[Rik]

I'm curious: why are you answering such a low effort question from 4.5 years ago?

[John D'Errico]

Answer: It is an easy way to gain site reputation.

[Purvaja]

Well, that was not my intention in answering. I am a beginner and in the process of learning. I started to build my competence and leveraged this forum. I started with solving some basic concepts and since no one attempted to answer this, I took up on this to help beginners like me.

I am looking forward to take up more challenging questions ahead! 😃