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().
Link to my notebook. https://github.com/irshadqemu/fasai_dl1/blob/master/Planet_amazon_resnet34.ipynb