Hi Tobias,
The “rosenbrock” function is provided within the Deep Learning toolbox. Here is the code for the same:
function [y,dydx] = rosenbrock(x)
y = 100*(x(2) - x(1).^2).^2 + (1 - x(1)).^2;
dydx = dlgradient(y,x);
end
For more information, refer the following documentation: