Mercurial > octave-antonio
view scripts/special-matrix/wilkinson.m @ 20162:2645f9ef8c88 stable
doc: Update more docstrings to have one sentence summary as first line.
Reviewed specfun, special-matrix, testfun, and time script directories.
* scripts/specfun/expint.m, scripts/specfun/isprime.m,
scripts/specfun/legendre.m, scripts/specfun/primes.m,
scripts/specfun/reallog.m, scripts/specfun/realsqrt.m,
scripts/special-matrix/gallery.m, scripts/special-matrix/hadamard.m,
scripts/special-matrix/hankel.m, scripts/special-matrix/hilb.m,
scripts/special-matrix/invhilb.m, scripts/special-matrix/magic.m,
scripts/special-matrix/pascal.m, scripts/special-matrix/rosser.m,
scripts/special-matrix/toeplitz.m, scripts/special-matrix/vander.m,
scripts/special-matrix/wilkinson.m, scripts/testfun/assert.m,
scripts/testfun/demo.m, scripts/testfun/example.m, scripts/testfun/fail.m,
scripts/testfun/rundemos.m, scripts/testfun/runtests.m,
scripts/testfun/speed.m, scripts/time/asctime.m, scripts/time/calendar.m,
scripts/time/clock.m, scripts/time/ctime.m, scripts/time/datenum.m,
scripts/time/datestr.m, scripts/time/datevec.m, scripts/time/etime.m,
scripts/time/is_leap_year.m, scripts/time/now.m, scripts/time/weekday.m:
Update more docstrings to have one sentence summary as first line.
author | Rik <rik@octave.org> |
---|---|
date | Sun, 03 May 2015 17:00:11 -0700 |
parents | 9fc020886ae9 |
children |
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## Copyright (C) 1999-2015 Peter Ekberg ## ## 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/>. ## -*- texinfo -*- ## @deftypefn {Function File} {} wilkinson (@var{n}) ## Return the Wilkinson matrix of order @var{n}. ## ## Wilkinson matrices are symmetric and tridiagonal with pairs of nearly, but ## not exactly, equal eigenvalues. They are useful in testing the behavior and ## performance of eigenvalue solvers. ## ## @seealso{rosser, eig} ## @end deftypefn ## Author: Peter Ekberg ## (peda) function retval = wilkinson (n) if (nargin != 1) print_usage (); endif if (! (isscalar (n) && n >= 0 && (n == fix (n)))) error ("wilkinson: N must be a non-negative integer"); endif side = ones (n-1, 1); center = abs (-(n-1)/2:(n-1)/2); retval = diag (side, -1) + diag (center) + diag (side, 1); endfunction %!assert (wilkinson (0), []) %!assert (wilkinson (1), 0) %!assert (wilkinson (2), [0.5,1;1,0.5]) %!assert (wilkinson (3), [1,1,0;1,0,1;0,1,1]) %!assert (wilkinson (4), [1.5,1,0,0;1,0.5,1,0;0,1,0.5,1;0,0,1,1.5]) ## Test input validation %!error wilkinson () %!error wilkinson (1,2) %!error <N must be a non-negative integer> wilkinson (ones (2)) %!error <N must be a non-negative integer> wilkinson (-1) %!error <N must be a non-negative integer> wilkinson (1.5)