20. The method of claim 19 , wherein the grouping step comprises estimating singular values corresponding to at least one of the probabilistic distributions on parts and selecting actual singular values of matrix A that correspond to the estimated singular values.
20. The method of claim 19 , wherein the grouping step comprises estimating singular values corresponding to at least one of the probabilistic distributions on parts and selecting actual singular values of matrix A that correspond to the estimated singular values. 22. The method of claim 20 , wherein the step of estimating singular values corresponding to a probabilistic distributions on parts comprises the steps of: generating characteristic coefficients; forming a special characteristic polynomial; and solving for the roots of the characteristic polynomial, wherein multiplying the roots by the number of samples related to corresponding probabilistic distributions on parts and then taking a square-root yields the estimated singular values.