Making Sure the Graphs I Plot is Correct

[nilshg]

On (3) you can just do xticks = -9:0.2:9.

(1) and (2) aren’t really questions for a plotting package, but for packages which implement methods to find saddle points or extrema - just have a google around or search this forum to find discussions like

Finding saddle point

@cortner note that this problem has an explicit saddle separation: min_x max_y f(x,y). That simplifies things a lot, and might actually be a good basis to think about robust algorithms @amrods essentially yes. But you don’t know how to compute derivatives of F(x) = |nabla f(x)| so you don’t want to do a Newton-like iteration. Also Newton doesn’t see minima, saddles or maxima, it just sees critical points (and so if you start near a minimum it will converge to that). OTOH flipped gradient iterat…