Fit Multi Dimensional Polynomial

% This is example how to fit multi dimensional polynomial
%
% The example fits between CMYK to LAB
% It assume that LAB is a polynomial function of CMYK
% The polynomial is limited by the deg, which is max(sum(n1,n2,n3,n4))
% The polynomial is in the form:
%
% Y=...
% a(1) * (c^0) * (m^0) * (y^0) * (k^0) +...
% a(2) * (c^1) * (m^0) * (y^0) * (k^0) +...
% a(3) * (c^0) * (m^1) * (y^0) * (k^0) +...
% a(4) * (c^0) * (m^0) * (y^1) * (k^0) +...
% a(5) * (c^0) * (m^0) * (y^0) * (k^1) +...
% ...
%
% The example is base on the mathematics in:
% http://mathworld.wolfram.com/LeastSquaresFittingPolynomial.html