Dear students,
there was a small error in slide 40 of today's lecture on Self-Organizing Topological Maps. Although the Delta Weight (equation 1) includes a discount factor (proportional to the product of the weight vector and the Psi function) similarly to Oja's rule, the discount factor must be subtracted from the result of the product (eta x_i y_j) and not from the input x_j, as in Oja's rule. I have corrected the slides by removing the brackets surrounding the subtraction and uploaded the new pdf. Those who took notes this morning may simply make the corrections directly to the notes (delete the brackets surrounding the subtraction). The others can use the corrected slides. My oral explanation remains correct because indeed this learning rule is inspired by Oja's learning rule, although it is not identical.
Thanks to the student who pointed out the math inconsistency of the original version!
See you next week,
Dario Floreano
