matlab error minus , matrix dimensions must agree

Question

Hi why am i getting this error?

x = linspace(-1,1,20);
y = linspace(-2,2,40);
z = (1.+sin(pi.*x)).*((3.+cos(1.065.*y)).^2).*exp(-x.^2 -(y.^2)./4);

??? Error using ==> minus Matrix dimensions must agree.

Answer 1

Because x and y are not the same size. What you likely want to use here is meshgrid.

The code would be something like:

      [x,y] = meshgrid(linspace(-1,1,20),linspace(-2,2,40));
      z = (1.+sin(pi.*x)).*((3.+cos(1.065.*y)).^2).*exp(-x.^2 -(y.^2)./4);

Then you can visualize like:

      surf(x,y,z)

And get stuff like this: