An RBF whose response is dictated by a Gaussian kernel. More specifically, this RBF returns
e^(-1 * d(x, c)^2 / e^2), where d(x, c) is the distance from a query state s to a defined "center,"
c, of this RBF and e is a bandwidth parameter on (0, +infinity) that affects the range of influence of this RBF. The
larger the bandwidth value, the more uniform the response it gives to any arbitrary input state. The distance
between the query state and the center state is determined by a provided distance function.
Anubhav Malhotra and Daniel Fernandez and Spandan Dutta
Returns a response value to an input state that is a function of the distance between the input and this unit's center state.
The less distant a query state is from this unit's center state, the greater the resposne value.