Mercurial > octave
view scripts/general/nextpow2.m @ 31706:597f3ee61a48 stable
update Octave Project Developers copyright for the new year
author | John W. Eaton <jwe@octave.org> |
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date | Fri, 06 Jan 2023 13:11:27 -0500 |
parents | 075443476dfb |
children | 2e484f9f1f18 |
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######################################################################## ## ## Copyright (C) 1995-2023 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{n} =} nextpow2 (@var{x}) ## Compute the exponent for the smallest power of two larger than the input. ## ## For each element in the input array @var{x}, return the first integer ## @var{n} such that ## @tex ## $2^n \ge |x|$. ## @end tex ## @ifnottex ## 2^n @geq{} abs (x). ## @end ifnottex ## ## @seealso{pow2, log2} ## @end deftypefn function n = nextpow2 (x) if (nargin < 1) print_usage (); endif if (! isnumeric (x)) error ("nextpow2: X must be numeric"); endif n = ceil (log2 (abs (x))); n(x == 0) = 0; # special case endfunction %!assert (nextpow2 (16), 4) %!assert (nextpow2 (17), 5) %!assert (nextpow2 (31), 5) %!assert (nextpow2 (-16), 4) %!assert (nextpow2 (-17), 5) %!assert (nextpow2 (-31), 5) %!assert (nextpow2 (1:17), [0 1 2 2 3 3 3 3 4 4 4 4 4 4 4 4 5]) %!assert <*62947> (nextpow2 (0.5), -1) %!assert <*62947> (nextpow2 (0.6), 0) ## Special cases %!assert (nextpow2 (0), 0) %!assert (nextpow2 (1), 0) %!assert (nextpow2 (Inf), Inf) %!assert (nextpow2 (-Inf), Inf) %!assert (nextpow2 (NaN), NaN) %!assert (nextpow2 ([1, Inf, 3, -Inf, 9, NaN]), [0, Inf, 2, Inf, 4, NaN]) ## Test input validation %!error <Invalid call> nextpow2 () %!error <X must be numeric> nextpow2 ("t")