Growing Neural Gas , Growing Neural Gas with Utility

5.4.6

No new Nodes

No new nodes will be inserted.

Utility

Switches from GNG to GNG-U and back. The value (k) determines the deletion of the unit with the smallest utility U_i ($i := arg\ min_cU_c$), if the utility value falls below a certain fraction of the error variable E_q: k < E_q/U_i.

Lambda

If the number of input signals generated so far is an integer multiple of this value ($\lambda$), insert a new node.

max. Edge Age

Remove edges with an age larger than this value (a_max). If this results in nodes having no emanating edges, remove them as well.

Epsilon winner

Move the winner node towards the input signal by this fraction of the total distance ($\epsilon_b$).

Epsilon neighbor

Move the neighbors of the winner node towards the input signal by this fraction of the total distance ($\epsilon_n$).

alpha

Decrease the error variables of the nodes neighboring to the newly inserted node by a fraction of this size ($\alpha$).

beta

Decrease the error variables of all nodes by a fraction of this size ($\beta$).