/usr/share/octave/packages/linear-algebra-2.2.0/@kronprod/mldivide.m is in octave-linear-algebra 2.2.0-1build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 | ## 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
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