After one has described the net one must press 
to
generate the net in SNNS. The weights of the links are set to the
default value 
. Therefore one must initialize the net before one
starts learning. The net created has the default name
SNNS_NET.net. If a net already exists in SNNS a warning is issued
before it is replaced. If the network generated happens to have two
units with more than one connection in the same direction between them
then SNNS sends the error message ``Invalid Target''.