Results for .mat inputs are computed for all data elements and not only the in-mask elements

[BryanGuillaume]

The contrast and statistic results for .mat inputs are computed for all data elements while it should suffice to do it for the in-mask elements only. This is not a bug per se as the out-mask results are not of interest, but this is unnecessary and this could potentially yield warning or error message.

It seems that the change needs to be done in swe_contrasts.m. For example,

SwE-toolbox/swe_contrasts.m

Lines 143 to 146 in 35d549e

	if isMat
	beta = importdata(Vbeta);
	S = size(beta,2);
	end

shows that S, which is supposed to represent the number of in-mask elements is set to the total number of elements, which is wrong. I believe the main issue comes from the way the data is loaded in memory. For images, we can load directly the in-mask elements while for .mat files, it seems necessary to load everything and then select the in-mask elements, which is not done here.