ghbourhood size.

<p><CODE>options(16)</CODE> is the final learning rate; default value is the same
as the initial learning rate.

<p><CODE>options(17)</CODE> is the initial neighbourhood size; default 0.5*maximum
map size.

<p><CODE>options(18)</CODE> is the initial learning rate; default 0.9.  This parameter
must be positive.

<p><h2>
Examples
</h2>
The following example performs on-line training on a SOM in two stages:
ordering and convergence.
<PRE>

net = som(nin, [8, 7]);
options = foptions;

<p>% Ord