Mercurial > octave-nkf
view scripts/miscellaneous/list_primes.m @ 20647:05c77bc1d204
fix typo in changeset 01586012300e
* scripts/ode/ode45.m: count 6 fevals for each time the dorpri
stepper is invoked (not 7)
author | Carlo de Falco <carlo.defalco@polimi.it> |
---|---|
date | Mon, 12 Oct 2015 22:57:17 +0200 |
parents | 4197fc428c7d |
children |
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## Copyright (C) 1993-2015 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/>. ## -*- texinfo -*- ## @deftypefn {Function File} {} list_primes () ## @deftypefnx {Function File} {} list_primes (@var{n}) ## List the first @var{n} primes. ## ## If @var{n} is unspecified, the first 25 primes are listed. ## @seealso{primes, isprime} ## @end deftypefn ## Author: jwe function retval = list_primes (n = 25) if (nargin > 1) print_usage (); elseif (! isreal (n) || ! isscalar (n)) error ("list_primes: N must be a real scalar"); endif n = floor (n); if (n < 1) retval = []; return; elseif (n == 1) retval = 2; return; endif list = primes (n * log (5 * n)); if (numel (list) < n) ## Algorithm tested up to n=10,000 without failure. error ("list_primes: Algorithm failed. Try primes (n*log (6*n))(1:n)"); endif retval = list(1:n); endfunction %!assert (list_primes (), [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, ... %! 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]) %!assert (list_primes (5), [2, 3, 5, 7, 11]) %!assert (list_primes (0), []) %!assert (list_primes (1), [2]) ## Test input validation %!error list_primes (1, 2) %!error <N must be a real scalar> list_primes (i) %!error <N must be a real scalar> list_primes ([1 2])