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!