The HTM Spatial Pooler: a neocortical algorithm for online sparse distributed coding


@ycui, @subutai,

Minor error in the sentence above equation (10): “Finally, the boost
factor bi is then updated based on the difference between ai(t) and
<a¯i(t)> as shown in Figure 1D.” I guess it should say “between a¯i(t)
and <a¯i(t)>” (note the overline on the first a¯i) as per equation (10).


Yes, he is no longer at Numenta.

Hmm, I’m troubled by this too. I actually had no idea this was turned on by default. We should rerun without it and see if it makes a difference. I created an internal task to check this. Thank you for pointing this out.

Yeah, thanks! :slight_smile:


Thanks @subutai .



We turned off perm boosting and compared to the results reported in the SP paper - there is no difference in results. We also observe no difference in results when we increase the permanence boosting value to 0.2, which leads us to suspect that very few columns are eligible for permanence boosting, with the rest of the SP parameters set as described in the sp_params script.

You can play around with the permanence boosting parameter using setSynPermBelowStimulusInc().


Hi @vasudha.kowtha,

Thanks, good to know.

– Rik