Works well, however, I routinely get a "divide by zero" warning at line 65, even when using a hyperbolic paraboloid:
[x,y]=meshgrid(-3:.25:3,-3:.25:3);
tri=delaunay(x,y);
z=0.25*x.^2-0.25*y.^2;
Also, is please be more specific in defining output of which is minimum/maximum curvature, k1 or k2. Thanks!