Why is this "z=x.*exp(-X.^2-Y.^2) " required?

[x,y]=meshgrid(-2:.2:2);
z=x.*exp(-X.^2-Y.^2);

why is z=.... required??? and also why is (-X.^2-Y.^2)??

Answer 1

[Walter Roberson]

The z= part is not required. The (-X.^2-Y.^2) part is not required either. However, as long as you have exp() you need to provide some argument to it.

For example, the following would be valid MATLAB code:

[x,y]=meshgrid(-2:.2:2);
x.*exp(-1);

However, it does not do anything useful.

I suspect that you are looking for something closer to

[x, y] = meshgrid(-2:.2:2);
z = x .* exp(-x.^2 - y.^2);
surf(x, y, z, 'edgecolor', 'none')
xlabel('x'); ylabel('y');