How to write a function that utilizes unit vectors?

I want to implement the following vector function in Matlab:

This function utilizes unit vectors, denoted here by , and . I know how to implement the functions for the different directions, but I don't know how to combine them into a single function that retains all vectorial components. Any help would be appreciated.

Answer 1

[Benjamin Großmann]

If you can calculate the vector components (i.e. directions) than you only have to arrange them into an array. Suppose that you have calculations for the single directions in functions f1, f2 and f3:

function F = vectorFunction(r, theta, phi)
    % calculate the directions
    F1 = f1(r, theta, phi);
    F2 = f2(r, theta, phi);
    F3 = f3(r, theta, phi);

    % arrange directions in array (here: column vector)
    F = [F1; F2; F3];
end

function out = f1(r, theta, phi)
    out = r + theta + phi;
end

function out = f2(r, theta, phi)
    out = r * theta * phi;
end

function out = f3(r, theta, phi)
    out = r * theta - phi;
end