Class HomeostaticMaxEnt

                                  object --+            
                                           |            
base.parameterizedobject.ParameterizedObject --+        
                                               |        
                  base.functionfamilies.OutputFn --+    
                                                   |    
                                   OutputFnWithState --+
                                                       |
                                                      HomeostaticMaxEnt

Implementation of homeostatic intrinsic plasticity from Jochen Triesch, ICANN 2005, LNCS 3696 pp.65-70.

A sigmoid activation function is adapted automatically to achieve desired average firing rate and approximately exponential distribution of firing rates (for the maximum possible entropy).

Note that this OutputFn has state, so the history of calls to it will affect future behavior. The plastic parameter can be used to disable changes to the state.

Also calculates average activity as useful debugging information, for use with ValueTrackingOutoutFn Average activity is calculated as an exponential moving average with a smoothing factor (smoothing). For more information see: NIST/SEMATECH e-Handbook of Statistical Methods, Single Exponential Smoothing http://www.itl.nist.gov/div898/handbook/pmc/section4/pmc431.htm