Matlab F(x,y,z) Plotting

Greetings,

I would like to plot a function i.e. f(x,y,z) = X.^4 - 2*X.^2 + Y.^2 + 2*Y*Z +2*Z.^2 for my backtracking optimization problem. I am able to plot the contour of f(x,y) questions with the code given below. But I couldn't even plot a contour such function. Any help would be appreciated.

xAxis = linspace(-1,2.5,1000);
yAxis = linspace(-1,2.5,1000);
zAxis = linspace(-1,2.5,1000);
[ X,Y ] = meshgrid(xAxis,yAxis);
Z = X.^2 + 5*Y.^2 ;
contour(X,Y,Z,30)

Best Regards,

Ömer

Answer 1

[Ameer Hamza]

You can use slice() to create a contour plot of your function at specified planes. Try this

xAxis = linspace(-1,2.5,100);
yAxis = linspace(-1,2.5,100);
zAxis = linspace(-1,2.5,100);
[X, Y, Z] = meshgrid(xAxis,yAxis,zAxis);
f = X.^4 - 2*X.^2 + Y.^2 + 2*Y.*Z +2*Z.^2;

x_planes = [1 2];
y_places = 0;
z_planes = [0.5 1];
slice(X, Y, Z, f, x_planes, y_places, z_planes);

Answer 2

[Drc]

y^2/b^2-x^2/a^2=z/c

I want this function in 3D

[Torsten]

Use "fimplicit3".