Performs Eigenvalue Decomposition using Householder QR Factorization
This function is adapted from the CERN Jet Java libraries, for it
the following copyright applies (see also, text on top of file)
Copyright (C) 1999 CERN - European Organization for Nuclear Research.
Function used to calculate the entropy of given vector of values
entropy = (1/sum)*{-sigma[i=1..P](Xi*log2(Xi)) + sum*log2(sum)}
where P is the length of the vector
Check whether the two integer vectors equal to each other
Two integer vectors are equal if all the elements are the
same, regardless of the order of the elements