The error surface for a linear neuron

• The error surface lies in a space with a horizontal axis for each weight and one vertical axis for the error. – It is a quadratic bowl. • i.e. the height can be expressed as a function of the weights without using powers higher than 2. Quadratics have constant curvature (because the second derivative must be a constant) – Vertical cross-sections are parabolas. – Horizontal cross-sections are ellipses.

w1

E

w

w2