Mercurial > octave
view libinterp/corefcn/sylvester.cc @ 23084:ef4d915df748
maint: Merge stable to default.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Mon, 23 Jan 2017 14:27:48 -0500 |
parents | 3a2b891d0b33 e9a0469dedd9 |
children | 092078913d54 |
line wrap: on
line source
/* Copyright (C) 1996-2016 John W. Eaton This file is part of Octave. Octave 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 of the License, or (at your option) any later version. Octave 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 Octave; see the file COPYING. If not, see <http://www.gnu.org/licenses/>. */ // Author: A. S. Hodel <scotte@eng.auburn.edu> #if defined (HAVE_CONFIG_H) # include "config.h" #endif #include "defun.h" #include "error.h" #include "errwarn.h" #include "ovl.h" DEFUN (sylvester, args, , doc: /* -*- texinfo -*- @deftypefn {} {@var{X} =} sylvester (@var{A}, @var{B}, @var{C}) Solve the Sylvester equation @tex $$ A X + X B = C $$ @end tex @ifnottex @example A X + X B = C @end example @end ifnottex using standard @sc{lapack} subroutines. For example: @example @group sylvester ([1, 2; 3, 4], [5, 6; 7, 8], [9, 10; 11, 12]) @result{} [ 0.50000, 0.66667; 0.66667, 0.50000 ] @end group @end example @end deftypefn */) { if (args.length () != 3) print_usage (); octave_value retval; octave_value arg_a = args(0); octave_value arg_b = args(1); octave_value arg_c = args(2); octave_idx_type a_nr = arg_a.rows (); octave_idx_type a_nc = arg_a.columns (); octave_idx_type b_nr = arg_b.rows (); octave_idx_type b_nc = arg_b.columns (); octave_idx_type c_nr = arg_c.rows (); octave_idx_type c_nc = arg_c.columns (); bool isfloat = arg_a.is_single_type () || arg_b.is_single_type () || arg_c.is_single_type (); if (arg_a.is_empty () || arg_b.is_empty () || arg_c.is_empty ()) { if (isfloat) return ovl (FloatMatrix ()); else return ovl (Matrix ()); } // Arguments are not empty, so check for correct dimensions. if (a_nr != a_nc) err_square_matrix_required ("sylvester", "A"); if (b_nr != b_nc) err_square_matrix_required ("sylvester", "B"); if (a_nr != c_nr || b_nr != c_nc) err_nonconformant (); if (isfloat) { if (arg_a.is_complex_type () || arg_b.is_complex_type () || arg_c.is_complex_type ()) { // Do everything in complex arithmetic; FloatComplexMatrix ca = arg_a.float_complex_matrix_value (); FloatComplexMatrix cb = arg_b.float_complex_matrix_value (); FloatComplexMatrix cc = arg_c.float_complex_matrix_value (); retval = Sylvester (ca, cb, cc); } else { // Do everything in real arithmetic. FloatMatrix ca = arg_a.float_matrix_value (); FloatMatrix cb = arg_b.float_matrix_value (); FloatMatrix cc = arg_c.float_matrix_value (); retval = Sylvester (ca, cb, cc); } } else { if (arg_a.is_complex_type () || arg_b.is_complex_type () || arg_c.is_complex_type ()) { // Do everything in complex arithmetic; ComplexMatrix ca = arg_a.complex_matrix_value (); ComplexMatrix cb = arg_b.complex_matrix_value (); ComplexMatrix cc = arg_c.complex_matrix_value (); retval = Sylvester (ca, cb, cc); } else { // Do everything in real arithmetic. Matrix ca = arg_a.matrix_value (); Matrix cb = arg_b.matrix_value (); Matrix cc = arg_c.matrix_value (); retval = Sylvester (ca, cb, cc); } } return retval; } /* %!assert (sylvester ([1, 2; 3, 4], [5, 6; 7, 8], [9, 10; 11, 12]), [1/2, 2/3; 2/3, 1/2], sqrt (eps)) %!assert (sylvester (single ([1, 2; 3, 4]), single ([5, 6; 7, 8]), single ([9, 10; 11, 12])), single ([1/2, 2/3; 2/3, 1/2]), sqrt (eps ("single"))) ## Test input validation %!error sylvester () %!error sylvester (1) %!error sylvester (1,2) %!error sylvester (1, 2, 3, 4) %!error <A must be a square matrix> sylvester (ones (2,3), ones (2,2), ones (2,2)) %!error <B must be a square matrix> sylvester (ones (2,2), ones (2,3), ones (2,2)) %!error <nonconformant matrices> sylvester (ones (2,2), ones (2,2), ones (3,3)) */