Python 3 Migration: SP Overlay Test

Engineering NuPIC
1

This test is using a SpatialPooler to generate some data. Here is the call into nupic.core:

      onCells = numpy.zeros(columnDimensions)
      spImpl.compute(spInput, True, onCells)
      spOutput.append(onCells.tolist())
      activeCoincIndices = set(onCells.nonzero()[0])

The onCells array is filled mostly with “0.0” and if all values are zero the activeCoincIndices array would be empty. On python 3 that is the case whereas on python 2.7 there are some non zero values. The things is that all the non zero values are very small, I mean small as “2.1219957909652723e-314”. I have checked:

      if(len([x for x in onCells if abs(x) > 0.00000000001]) > 0):
        print 'good values'

and onCells never seem to have anything useful in it. Is that a correct observation?

In any event, when there are only 0.0 in onCells the code will fault because of division by zero.

factor = max(summ)*len(summ)/sum(summ)

Is it correct to fix the test like this:

    if(len([x for x in summ if x!=0]) > 0):
      zeros = len([x for x in summ if x==0])
      factor = max(summ)*len(summ)/sum(summ)

Thanks!

2

Are you saying that in python 3 numpy.zeros() is returning arrays with non zero values?

3

No, the line

spImpl.compute(spInput, True, onCells)

is filling in the onCells array.

The issue here is that the non zero values are very very small. Like “2.1219957909652723e-314”

Would you be able to debug that? I just like to know if you have reasonable values.

4

If you give me a link to the specific test I can try debugging in python2 and let you know if I see the same thing.

5

This is where the test starts:

After the first call of

spImpl.compute(spInput, True, onCells)

do you have any non zero values that are different to these “2.1219957909652723e-314”?

6

I will help you with this and Python 3 Migration: Backtracking tests within the next week. I have some other things to do right away.

7

Please, take your time. I got plenty of other things to work on…

Thanks for your offer!

8

OK, I just saw there was a nupic bug fix from 2018/1/16 which is related to this issue. At least now the values make sense that are returned from the SpatialPooler compute().

9

This issue is closed. Using the correct numpy datatype solved the issue.

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