噓~

1. 簡單的plot

https://sites.google.com/site/octavetech/octave_introduction/plotting/high_level_plotting/two_dimensional_plots

figure;

plot(x1,y1,'rx;Training Data;','MakerSize',10);

xlabel('x');

hold on;

plot(x1,y2,'b-;Fitting Result;')

hold off;

2. 3D plot

right hand picture: surf(x,y,z)

or

left hand picture: plot3(x,y,z)

https://www.gnu.org/software/octave/doc/interpreter/Three_002dDimensional-Plots.html

3. 等高線圖

contour(x,y,z, logspace(-2,3,20))

等高線值由10^-2 =0.01 ~ 10^3=100 間取20個值