I am getting error while using gradient(f​unction,ve​ctor) the error is: Error using zeros||| Error in gradient (line 64) g = zeros(size(f),class(f)); % case of singleton dimension

f_str = input('enter the function: ','s');

f = inline(f_str);

n = nargin(f); %%provides no. of arguments

X_char = argnames(f)

X = sym('X', [n,1]) %%declare matrix X of dimension nx1 as sym

i = 1; while (i<=n)

    X(i,1) = X_char(i,1)

    i = i+1;
end

X = X(:) %% convert X from column matrix to column vector

gradient(f,X)