title: How to plot a 2d gaussian with different sigma?
body: <p>I am trying to make and plot a 2d gaussian with two different standard deviations. They give the equation on mathworld: <a href="http://mathworld.wolfram.com/GaussianFunction.html" rel="noreferrer">http://mathworld.wolfram.com/GaussianFunction.html</a> but I can't seem to get a proper 2D array which centers it around zero. </p>
  
  <p>I got this, but it does not quite work. </p>
  
  <pre><code>x = np.array([np.arange(size)])
  y = np.transpose(np.array([np.arange(size)]))
  
  psf  = 1/(2*np.pi*sigma_x*sigma_y) * np.exp(-(x**2/(2*sigma_x**2) + y**2/(2*sigma_y**2))) 
  </code></pre>