Mercurial > octave
view libinterp/corefcn/sylvester.cc @ 20909:03e4ddd49396
omit unnecessary nargout checks
* paramdemo.cc, __ichol__.cc, __ilu__.cc, balance.cc, dassl.cc,
eig.cc, ellipj.cc, filter.cc, givens.cc, hess.cc, lsode.cc, lu.cc,
mgorth.cc, nproc.cc, pr-output.cc, quad.cc, quadcc.cc, sylvester.cc,
urlwrite.cc, variables.cc, ccolamd.cc, colamd.cc, qr.cc: Don't call
print_usage based on value of nargout. If nargout doesn't alter
function behavior and returning extra values is inexpensive, simply
return them instead of checking nargout.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Wed, 16 Dec 2015 11:41:11 -0500 |
parents | 1142cf6abc0d |
children | a3359fe50966 |
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/* Copyright (C) 1996-2015 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> #ifdef HAVE_CONFIG_H #include <config.h> #endif #include "defun.h" #include "error.h" #include "gripes.h" #include "oct-obj.h" #include "utils.h" DEFUN (sylvester, args, nargout, "-*- texinfo -*-\n\ @deftypefn {} {@var{X} =} syl (@var{A}, @var{B}, @var{C})\n\ Solve the Sylvester equation\n\ @tex\n\ $$\n\ A X + X B = C\n\ $$\n\ @end tex\n\ @ifnottex\n\ \n\ @example\n\ A X + X B = C\n\ @end example\n\ \n\ @end ifnottex\n\ using standard @sc{lapack} subroutines.\n\ \n\ For example:\n\ \n\ @example\n\ @group\n\ sylvester ([1, 2; 3, 4], [5, 6; 7, 8], [9, 10; 11, 12])\n\ @result{} [ 0.50000, 0.66667; 0.66667, 0.50000 ]\n\ @end group\n\ @end example\n\ @end deftypefn") { octave_value retval; if (args.length () != 3) print_usage (); 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 (); int arg_a_is_empty = empty_arg ("sylvester", a_nr, a_nc); int arg_b_is_empty = empty_arg ("sylvester", b_nr, b_nc); int arg_c_is_empty = empty_arg ("sylvester", c_nr, c_nc); bool isfloat = arg_a.is_single_type () || arg_b.is_single_type () || arg_c.is_single_type (); if (arg_a_is_empty > 0 && arg_b_is_empty > 0 && arg_c_is_empty > 0) if (isfloat) return octave_value (FloatMatrix ()); else return octave_value (Matrix ()); else if (arg_a_is_empty || arg_b_is_empty || arg_c_is_empty) return retval; // Arguments are not empty, so check for correct dimensions. if (a_nr != a_nc) { gripe_square_matrix_required ("sylvester: input A"); return retval; } else if (b_nr != b_nc) { gripe_square_matrix_required ("sylvester: input B"); return retval; } else if (a_nr != c_nr || b_nr != c_nc) { gripe_nonconformant (); return retval; } 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 <input A: .* must be a square matrix> sylvester (ones (2,3), ones (2,2), ones (2,2)) %!error <input 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)) */