Blicharsky's relaxation theory invariants.
These are the interaction anisotropy parameters that occur in many relaxation theory expressions. First given by Equations 20-21 in http://doi.org/10.1515/zna-1972-1012, but with an error and a typo in Equation 21, which have been corrected.
A - a real 3x3 matrix
Lsq - first rank invariant Dsq - second rank invariant
This function is not sensitive to the trace of the matrix.
Version 2.1, authors: Ilya Kuprov