Mercurial > octave-nkf
view libinterp/corefcn/mgorth.cc @ 18518:0bdecd41b2dd stable
correctly size fread result (bug #41648)
* oct-stream.cc (octave_base_stream::read): When reading to EOF, don't
add extra column to the result matrix if the number of elements found
is an exact multiple of the number of rows requested.
Avoid mixed signed/unsigned comparisons.
* io.tst: New tests.
author | John W. Eaton <jwe@octave.org> |
---|---|
date | Sat, 22 Feb 2014 13:06:18 -0500 |
parents | 175b392e91fe |
children | 4197fc428c7d |
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/* Copyright (C) 2009-2013 Carlo de Falco Copyright (C) 2010 VZLU Prague 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/>. */ #ifdef HAVE_CONFIG_H #include <config.h> #endif #include "oct-norm.h" #include "defun.h" #include "error.h" #include "gripes.h" template <class ColumnVector, class Matrix, class RowVector> static void do_mgorth (ColumnVector& x, const Matrix& V, RowVector& h) { octave_idx_type Vc = V.columns (); h = RowVector (Vc + 1); for (octave_idx_type j = 0; j < Vc; j++) { ColumnVector Vcj = V.column (j); h(j) = RowVector (Vcj.hermitian ()) * x; x -= h(j) * Vcj; } h(Vc) = xnorm (x); if (real (h(Vc)) > 0) x = x / h(Vc); } DEFUN (mgorth, args, nargout, "-*- texinfo -*-\n\ @deftypefn {Built-in Function} {[@var{y}, @var{h}] =} mgorth (@var{x}, @var{v})\n\ Orthogonalize a given column vector @var{x} with respect to a set of\n\ orthonormal vectors comprising the columns of @var{v}\n\ using the modified Gram-Schmidt method.\n\ On exit, @var{y} is a unit vector such that:\n\ \n\ @example\n\ @group\n\ norm (@var{y}) = 1\n\ @var{v}' * @var{y} = 0\n\ @var{x} = [@var{v}, @var{y}]*@var{h}'\n\ @end group\n\ @end example\n\ \n\ @end deftypefn") { octave_value_list retval; int nargin = args.length (); if (nargin != 2 || nargout > 2) { print_usage (); return retval; } octave_value arg_x = args(0); octave_value arg_v = args(1); if (arg_v.ndims () != 2 || arg_x.ndims () != 2 || arg_x.columns () != 1 || arg_v.rows () != arg_x.rows ()) { error ("mgorth: V should be a matrix, and X a column vector with" " the same number of rows as V."); return retval; } if (! arg_x.is_numeric_type () && ! arg_v.is_numeric_type ()) { error ("mgorth: X and V must be numeric"); } bool iscomplex = (arg_x.is_complex_type () || arg_v.is_complex_type ()); if (arg_x.is_single_type () || arg_v.is_single_type ()) { if (iscomplex) { FloatComplexColumnVector x = arg_x.float_complex_column_vector_value (); FloatComplexMatrix V = arg_v.float_complex_matrix_value (); FloatComplexRowVector h; do_mgorth (x, V, h); retval(1) = h; retval(0) = x; } else { FloatColumnVector x = arg_x.float_column_vector_value (); FloatMatrix V = arg_v.float_matrix_value (); FloatRowVector h; do_mgorth (x, V, h); retval(1) = h; retval(0) = x; } } else { if (iscomplex) { ComplexColumnVector x = arg_x.complex_column_vector_value (); ComplexMatrix V = arg_v.complex_matrix_value (); ComplexRowVector h; do_mgorth (x, V, h); retval(1) = h; retval(0) = x; } else { ColumnVector x = arg_x.column_vector_value (); Matrix V = arg_v.matrix_value (); RowVector h; do_mgorth (x, V, h); retval(1) = h; retval(0) = x; } } return retval; } /* %!test %! for ii=1:100 %! assert (abs (mgorth (randn (5, 1), eye (5, 4))), [0 0 0 0 1]', eps); %! endfor %!test %! a = hilb (5); %! a(:, 1) /= norm (a(:, 1)); %! for ii = 1:5 %! a(:, ii) = mgorth (a(:, ii), a(:, 1:ii-1)); %! endfor %! assert (a' * a, eye (5), 1e10); */