That is a little difficulty to explain. In short: I am calculating a
Gaussian function for an image which describes the probability densities of
the colour distribution. This is used for image segmentation.
As a part of this calculation a covariance matrix (I don't know if that's
the proper term in english) is needed. In order to calculate the covariance
matrix I need the entry-by-entry product.
(this explanation might not be totally correct - I am unfortunately not the
mathematical master mind of this project)