 fitting a Gaussian mixture model
with circular covariances using the EM algorithm through a call to
<CODE>rbfsetbf</CODE>.  (The mixture model is
initialised using a small number of iterations of the K-means algorithm.)
If the activation functions are Gaussians, then the basis function widths
are then set to the maximum inter-centre squared distance.

<p>For linear outputs, 
the hidden to output
weights that give rise to the least squares solution
can then be determined using the pseudo-inverse. 