%% Plot Surface Normals 
% Plot the surface normals of the function $z = xe^{-x^2-y^2}$. 

% Copyright 2015 The MathWorks, Inc.


[X,Y] = meshgrid(-2:0.25:2,-1:0.2:1);
Z = X.* exp(-X.^2 - Y.^2);
[U,V,W] = surfnorm(X,Y,Z);

figure
quiver3(X,Y,Z,U,V,W,0.5)

hold on
surf(X,Y,Z)
view(-35,45)
axis([-2 2 -1 1 -.6 .6])
hold off