logical indicating the need for SVD for the
coeffient matrix int the output
References
Mukherjee, A. and Zhu, J. (2011) Reduced rank ridge regression and its
kernal extensions.
Mukherjee, A., Chen, K., Wang, N. and Zhu, J. (2015) On the degrees of
freedom of reduced-rank estimators in multivariate
regression. Biometrika, 102, 457--477.