-IntegrationFunction = ->
+IntegrationFunction = (incrementAccumulators) ->
 
   # if we've already calculated a currentValue for ourselves this step, return it
   if @currentValue
     return @currentValue
+  if @isAccumulator and not incrementAccumulators
+    return @previousValue
 
   links = @inLinks()
   count = links.length

    node.previousValue = node.currentValue
    node.currentValue = null

  evaluateNode: (node) ->
    node.currentValue = node.getCurrentValue()

  # create an object representation of the current timeStep and add
  # it to the current bundle of frames.

      # push values down chain
      for i in [0...10]
        _.each @nodes, (node) => @nextStep node  # toggles previous / current val.
        _.each @nodes, (node) => @evaluateNode node, i is 0

      # accumulate values for later averaging
      for i in [0...20]
