How to plot 3D surface with vector-input function?

I have a function that takes array inputs as arguments.

FUN = @(x) = x(1).^2+x(2).^2

When I try to use fsurf (ie. fsurf(FUN) or fsurf(FUN,[0 100 0 100])), the surface will not plot, and an error will appear (Error updating FunctionSurface).

surf or meshgrid don't work either.

What can I do to have this function plot, instead of un-vectorizing the handle (ie. FUN = @(x1,x2) x1.^2+x2.^2)?

Answer 1

[Star Strider]

The function you coded:

FUN = @(x) = x(1).^2+x(2).^2;

will only take the first 2 elements of ‘x’ (whatever it is), and will return a scalar.

You need to restate it as:

FUN = @(x1,x2) x1.^2+x2.^2;

for example, to produce a surface:

[X1,X2] = meshgrid(-1:0.5:1);

figure
surf(X1, X2, FUN(X1,X2))
grid on

.

[ejk]

I take it that there's no way to do this without restating the function with two separate variables?

[Star Strider]

That is correct.

I could not devise a way to do it otherwise, and I doubt that one exists.