<https://github.com/lonesword/nupichelloworld/blob/master/helloworld.py> Tinkering a bit, I came to notice that if I used the SpatialPooler class instead of FlatSpatialPooler, I get the same set of active columns for the same input. But it takes much longer to get the results and the 'busy' light of my computer stays on for a really long time. From what I read, I had assumed that the only real difference between the normal spatial pooler and the flat spatial pooler was the lack of topology. But since both of them returned different results I think FSP is minimalistic in much more ways (the SP returns the expected result, while the FSP returns a new result for the same input vector which was not what I had expected). But I'd still like to know why the Flat SP returned different set of active columns for the same input.
On Sun, Feb 23, 2014 at 11:19 AM, Kevin Martin <[email protected]>wrote: > I'm on my way to writing a 'hello world' equivalent for nupic. I decided > to work with a flat spatial pooler since it has no topology. I was able to > send in an input vector and get the list of active columns. The source code > is hosted here : > > https://github.com/lonesword/nupichelloworld/blob/master/helloworld.py > > I was under the assumption that similar inputs to the spatial pooler > results in similar SDRs. That is, if I give the same input twice, it is > expected to produce the same SDRs. > > However, sending the same input vector to the compute() function returns a > different set of active columns every time. I'm pasting the code snippet > here : > > for i in range(10): > example.flat.compute(testinput,True,active) > for i in range(4096): > if active[i]!=0: > print i, > print " " > active[0:]=0 > > flat is an object of FlatSpatialPooler, > testinput is the input array, > active is the active list of columns. > > I got a different set of active columns for each iteration. Why is this > so? I'm feeding the pooler the same input vector each time. >
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