Permutes an unsymmetric matrix (square or rectangular) into its block upper triangular form. A translation of BTF into Dart by Richard Lincoln.
Copyright (C) 2004-2011 University of Florida.
Copyright (C) 2011-2014 Richard Lincoln.
BTF is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.