--- /dev/null
+## Copyright (C) 2010 Soren Hauberg
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3, or (at your option)
+## any later version.
+##
+## This program is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this file. If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} mldivide (@var{M1}, @var{M2})
+## XXX: Write documentation
+## @end deftypefn
+
+function retval = mldivide (M1, M2)
+ ## Check input
+ if (nargin != 2)
+ print_usage ();
+ endif
+
+ if (!ismatrix (M1) || !ismatrix (M2))
+ error ("mldivide: both input arguments must be matrices");
+ endif
+
+ if (rows (M1) != rows (M2))
+ error ("mldivide: nonconformant arguments (op1 is %dx%d, op2 is %dx%d)",
+ rows (M1), columns (M1), rows (M2), columns (M2));
+ endif
+
+ ## Take action depending on types
+ M1_is_KP = isa (M1, "kronprod");
+ M2_is_KP = isa (M2, "kronprod");
+
+ if (M1_is_KP && M2_is_KP) # Left division of Kronecker Products
+ error ("mldividide: this part not yet implemented as I'm lazy...");
+
+ elseif (M1_is_KP) # Left division of Kronecker Product and Matrix
+ ## XXX: Does this give the same minimum-norm solution as when using
+ ## XXX: full (M1) \ M2
+ ## XXX: ? It is the same when M1 is invertible.
+ retval = zeros (columns (M1), columns (M2));
+ for n = 1:columns (M2)
+ M = reshape (M2 (:, n), [rows(M1.B), rows(M1.A)]);
+ retval (:, n) = vec ((M1.A \ (M1.B \ M)')');
+ endfor
+
+ elseif (M2_is_KP) # Left division of Matrix and Kronecker Product
+ error ("mldividide: this part not yet implemented as I'm lazy...");
+
+ else
+ error ("mldivide: internal error for 'kronprod'");
+ endif
+endfunction