Almost useless feature called mean_change

[thautwarm]

tsfresh/tsfresh/feature_extraction/feature_calculators.py

Line 528 in 00884fb

def mean_change(x):

The result is equivalent to (x_last - x_first) / (n - 1).

If you do want this as a feature, (x[-1] - x[0])/(len(x) - 1) instead.

[nils-braun]

The optimized function is included, thanks to @blu3r4y
It might still be a useless feature, but you never know and that is why we have a feature selection ;-)