Hi Yuwei, Thanks for your response, things are much clearer now. I was
refering to this "if":

if permanence > 0 and self.predictedSegmentDecrement > 0:

Now, if I understand what you said, the connected synapses must be taken
into account as much as the non connected, but active ones, for the
formation of the matchingSegments and matchingCells variables. Their
decrement will only be made when the next element of the sequence arrives
and the matchingCells~Segments do not match with the current active cells.
Is that right?

On Mon, Apr 4, 2016 at 12:50 PM, Yuwei Cui <ywcui1...@gmail.com> wrote:

> Hello Sebastián,
>
> Please see my answers below:
>
>>
>> 1) What do the matchingSegments and matchingCells represent?
>>
>
> I think we recently include the logic here to model "long-term
> depression". That is if the segment has sufficient activity at time t, but
> does not become active at time t+1, it represents a potential false
> prediction and should be punished. "sufficient activity" here means number
> of active inputs is above minThreshold. matchingSegments and matchingCells
> are used to determine predicted but inactive cells at the next time step
> (see line 376 of learnOnSegments).
>
> This logic speeds up the forgetting of false predictions, but it should be
> used with caution. If your problems has multiple correct predictions, then
> it is OK to have some false predictions. Generally speaking, the ratio
> between permanenceIncrement and predictedSegmentDecrement determines how
> many multiple predictions can the model make at any time.
>
>
>> 2) minThreshold is supposed to be the minimum number of synapses a
>> segment must have in order to be considered for bursting, what does it do
>> here?
>>
>
> activationThreshold is the threshold for activation of a segment: if a
> segment has more than activationThreshold number of active synapses, it
> will fire a dendritic spike and depolarize the cell body.
>
> minThreshold is typically lower than activationThreshold and is only used
> in learning phase (not in inference phase). It are used in two places as
> far as I know.
>
> 1. If the number of synapses active on a segment is at least this
> threshold, it is selected as the best matching cell in a bursting column.
> (see function bestMatchingSegment)
>
> 2. It is used to determine predicted but inactive cells and segments as
> described above.
>
>
>> 3) As I see it, the if also grabs the permanneces above the connected
>> threshold, why is that?
>>
>
> I am not sure which "if" you are referring to here. Could you clarify your
> question?
>
> Yuwei
>
>

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