File: src/ENDal.cpp
    The C++ code for the preconditioned conjugate gradient solver in
    src/ENDal.cpp is from http://math.nist.gov/iml++/cg.h.txt with speedups
    from the Eigen C++ template library for linear algebra (eigen.tuxfamily.org)
    Copyright (C) 2011-2014 Gael Guennebaud <gael.guennebaud@inria.fr>
    published under the Mozilla Public License v. 2.0 (available at
    http://mozilla.org/MPL/2.0/).

File: src/PartialSort.c
    Copyright (C) for the C code of the partial quicksort algorithm in
    src/PartialSort.c belongs to Ariel Faigon (1987).

File: src/mscale.h
    The C code for the rho functions belongs to the authors of R package
    robustbase_0.92-5 with Copyright (C)
     * Peter Rousseeuw and Christophe Croux;
     * Valentin Todorov <valentin.todorov@chello.at>
     * Andreas Ruckstuhl <andreas.ruckstuhl@zhaw.ch>
     * Matias Salibian-Barrera <matias@stat.ubc.ca>
     * Tobias Verbeke <tobias.verbeke@openanalytics.eu>
     * Manuel Koller <mkoller@ispm.unibe.ch>
     * Martin Maechler <maechler@stat.math.ethz.ch>

File: src/ENLars.cpp
    Parts of the augmented LARS algorithm in src/ENLars.cpp are from
    the R package robustHD_0.5.1 with
    Copyright (C) Andreas Alfons <alfons@ese.eur.nl>
