Output argument "varargout{2}" (and maybe others) not assigned during call error?

Trying to plot contour lines with the associated gradient as arrows using the gradient function. My code is:

x = (-2:0.2:4);

y = (-2:0.2:2);

[x1 y1] = meshgrid(x,y);

h = (exp(-x1.^2-y1.^2))+0.5.*exp((-1.*(x1-2).^2)-y1.^2);

[C h]= contour (x,y,h);

hold all;

[hx,hy] = gradient(h);

quiver(x1, y1, hx, hy, 0.8)

I think I'm only getting one output from the gradient function, but shouldn't I be getting two?

Thanks, Chris.

Answer 1

[Sean de Wolski]

The problem is that you overwrite 'h' with the handle to the contourgroup so that h is no longer a two-dimensional matrix. Thus it cannot calculate the various components of the gradient and this error is thrown.

I agree that this error message could probably be better, I'll let our development team know.

[Chris Corbett]

Ah, yeah I see that now, quite obvious really.

Thank you.