function [obj grad hess]=rosenbrock(x)
  obj=(1-x(1))^2+100*(x(2)-x(1)^2)^2;
grad(1)=-2*(1-x(1))+200*(x(2)-x(1)^2)*(-2*x(1));
grad(2)=200*(x(2)-x(1)^2);
hess(1,1)=2+200*(-2*x(1))^2+200*(x(2)-x(1)^2)*(-2);
hess(1,2)=200*(-2*x(1));
hess(2,1)=hess(1,2);
hess(2,2)=200;
end