In lesson 2 Jeremy said TTA() return the log probs, and to obtain the actual probabilities we need to calculate the exponential (np.exp) of returned values.
while doing predictions on planet amazon data set, I got 48% f2 score when I used the np.exp of probs returned byTTA(). My accuracy jumped to 93% (also actual accuracy shown while running epochs).
There is also no negative value in probs returned by TTA().
I experienced something similar to what Irshad reported and also came across other threads mentioning changes to TTA.
I presume that at some point the notebook in question will get modified appropriately to reflect the changes to TTA. In the mean time an unexpected side benefit was all of the extra info learned from investigating