(PECL fann >= 1.0.0)
FANNConnection::__construct — The connection constructor
$from_neuron
   , int $to_neuron
   , float $weight
   )Create new connection and initialize its params. After creating the connection, only weight can be changed.
from_neuron
    The postion number of starting neuron.
to_neuron
    The postion number of terminating neuron.
weight
    The connection weight value.