Class JointNormalizingCFSheet

                                  object --+                    
                                           |                    
base.parameterizedobject.ParameterizedObject --+                
                                               |                
                  base.simulation.EventProcessor --+            
                                                   |            
                                      object --+   |            
                                               |   |            
          base.sheetcoords.SheetCoordinateSystem --+            
                                                   |            
                                    base.sheet.Sheet --+        
                                                       |        
                         base.projection.ProjectionSheet --+    
                                                           |    
                                             base.cf.CFSheet --+
                                                               |
                                                              JointNormalizingCFSheet

Known Subclasses:

JointNormalizingCFSheet_Continuous, LISSOM

A type of CFSheet extended to support joint sum-based normalization.

For L1 normalization, joint normalization means normalizing the sum of (the absolute values of) all weights in a set of corresponding CFs in different Projections, rather than only considering weights in the same CF.

This class makes it possible for a model to use joint normalization, by providing a mechanism for grouping Projections (see _port_match), plus a learn() function that computes the joint sums. Joint normalization also requires having ConnectionField store and return a norm_total for each neuron, and having an OutputFn that will respect this norm_total rather than the strict total of the ConnectionField's weights. At present, CFPOF_DivisiveNormalizeL1 and CFPOF_DivisiveNormalizeL1_opt do use norm_total; others can be extended to do something similar if necessary.

To enable joint normalization, you can declare that all the incoming connections that should be normalized together each have a dest_port of:

dest_port=('Activity','JointNormalize', 'AfferentGroup1'),

Then all those that have this dest_port will be normalized together, as long as an appropriate OutputFn is being used.