Smoothing window size differences between Picasso and PicassoPy

[HavardStridBuholdt]

Issue:

In Picasso the Matlab function smooth(y, span, method) is often used for preforming moving average or Savitzky-Golay smoothing. This function only allows odd window sizes (span) for these methods and will use span - 1 when span is even. See function documentation at: https://se.mathworks.com/help/curvefit/smooth.html#mw_7695cbca-640d-4029-a239-81c9dd8192d0

This is sometimes an issue when we compare Picasso to PicassoPy as our python smoothing functions allows both odd an even window sizes to be used, and the smoothing window sizes specified in the config files are often even. Thus the smoothing applied in Picasso and PicassoPy are for these scenarios different.

Additional information

The smoothing functions in the two versions handle edges differently. In picasso smooth(y, span, method) performs a sort of centered moving average filter with shrinking window size at the edges, while in PicassoPy we preform smoothing through a convolutional filter, commonly with no padding (adding NaN values at the edges to preserve the dimension) however, for functions that can not handle NaN values padding is used.