--- /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} det (@var{KP})
+## Compute the determinant of a Kronecker product.
+##
+## If @var{KP} is the Kronecker product of the @var{n}-by-@var{n} matrix @var{A}
+## and the @var{q}-by-@var{q} matrix @var{B}, then the determinant is computed
+## as
+##
+## @example
+## det (@var{A})^q * det (@var{B})^n
+## @end example
+##
+## If @var{KP} is not a Kronecker product of square matrices the determinant is
+## computed by forming the full matrix and then computing the determinant.
+## @seealso{det, @@kronprod/trace, @@kronprod/rank, @@kronprod/full}
+## @end deftypefn
+
+function retval = det (KP)
+ ## Check input
+ if (nargin != 1)
+ print_usage ();
+ endif
+
+ if (!isa (KP, "kronprod"))
+ error ("det: input argument must be of class 'kronprod'");
+ endif
+
+ if (!issquare (KP))
+ error ("det: argument must be a square matrix");
+ endif
+
+ ## Take action
+ [n, m] = size (KP.A);
+ [q, r] = size (KP.B);
+ if (n == m && q == r) # A and B are both square
+ retval = (det (KP.A)^q) * (det (KP.B)^n);
+ elseif (n*q == m*r) # kron (A, B) is square
+ ## XXX: Can we do something smarter here? We should be able to use the SVD...
+ retval = det (full (KP));
+ endif
+endfunction