"code never uses indicated local function" error?

This is my code for a class project:

x0 = 0.5;

tol = 0.00000005;

MaxIter = 20;

syms f(x)

f(x) = piecewise(x>=0,sqrt(x),x<0,-sqrt(-x));

function root = Newton(x0,tol,MaxIter)

format short e

error = 1;

it_count = 0;

fprintf('\n it_count x f(x) df(x) error \n')

while abs(error) > tol && it_count < MaxIter

fx = f(x0);

dfx = deriv_f(x0);

if df == 0

disp('The derivative is zero, stop')

return

end

x1 = x0 - fx/dfx;

error = x1 - x0;

x0 = x1;

it_count = it_count + 1;

end

if it_count >= MaxIter

disp('number iterates exceeded MaxIter, no accurate root found')

else

format long

root = x1

format short

end

end

For some reason I keep getting an error that says the local funciton "Newton" is unused. Honestly I'm not well-versed in Matlab, so I'm just working from a template so I don't understand how that function is unused. What do I do here?

Answer 1

[madhan ravi]

root = Newton(x0,tol,MaxIter) %this line have to be before the function root...