DMSpreading: Spreading activation default weights

[asmaloney]

If I'm reading the code correctly, DMSpreading takes zero or more buffers as arguments and sets their spreading activation weights to 1.0 by default:

  def __init__(self,memory,*buffers):
    MemorySubModule.__init__(self,memory)
    self.strength=1
    self.buffers=buffers
    self.weight={}
    for b in buffers: 
      self.weight[b]=1
    self.slots={}

Then I guess the user is supposed to reset the ones that are not supposed to be 1.0?

  spread = DMSpreading( memory, goal )
  spread.weight[goal] = 0.0

I believe these weights are the equivalent of ACT-R's activation spread parameters.

Here are the activation spread parameter defaults listed in the ACT-R manual:

buffer	ACT-R param	default
Aural buffer	:aural-activation	0.0
Aural-location buffer	:aural-location-activation	0.0
Goal buffer	:ga	0.0
Imaginal buffer	:imaginal-activation	1.0
Imaginal-action buffer	:imaginal-action-activation	0.0
Manual buffer	:manual-activation	0.0
Production buffer	:production-activation	0.0
Retrieval buffer	:retrieval-activation	0.0
Temporal buffer	:temporal-activation	0.0
Visual buffer	:visual-activation	0.0
Visual-location buffer	:visual-location-activation	0.0
Vocal buffer	:vocal-activation	0.0

So it seems like the default should be 0.0?

(Related to asmaloney/gactar#325)