Mercurial > octave
view scripts/general/logspace.m @ 30249:bc22395f60fa
maint: merge stable to default.
author | John W. Eaton <jwe@octave.org> |
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date | Fri, 22 Oct 2021 12:05:59 -0400 |
parents | 2d17a87740dd |
children | 01de0045b2e3 |
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######################################################################## ## ## Copyright (C) 1993-2021 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 {} {} logspace (@var{a}, @var{b}) ## @deftypefnx {} {} logspace (@var{a}, @var{b}, @var{n}) ## @deftypefnx {} {} logspace (@var{a}, pi, @var{n}) ## Return a row vector with @var{n} elements logarithmically spaced from ## @tex ## $10^{a}$ to $10^{b}$. ## @end tex ## @ifnottex ## 10^@var{a} to 10^@var{b}. ## @end ifnottex ## ## If @var{n} is unspecified it defaults to 50. ## ## If @var{b} is equal to ## @tex ## $\pi$, ## @end tex ## @ifnottex ## pi, ## @end ifnottex ## the points are between ## @tex ## $10^{a}$ and $\pi$, ## @end tex ## @ifnottex ## 10^@var{a} and pi, ## @end ifnottex ## @emph{not} ## @tex ## $10^{a}$ and $10^{\pi}$, ## @end tex ## @ifnottex ## 10^@var{a} and 10^pi, ## @end ifnottex ## in order to be compatible with the corresponding @sc{matlab} function. ## ## Also for compatibility with @sc{matlab}, return the right-hand side of ## the range ## @tex ## ($10^{b}$) ## @end tex ## @ifnottex ## (10^@var{b}) ## @end ifnottex ## when just a single value is requested. ## @seealso{linspace} ## @end deftypefn function retval = logspace (a, b, n = 50) if (nargin < 2) print_usage (); endif if (! (isscalar (a) && isscalar (b) && isscalar (n))) error ("logspace: arguments A, B, and N must be scalars"); endif npoints = fix (n); if (b == pi) b = log10 (pi); endif retval = 10 .^ (linspace (a, b, npoints)); endfunction %!test %! x1 = logspace (1, 2); %! x2 = logspace (1, 2, 10.1); %! x3 = logspace (1, -2, 10); %! x4 = logspace (1, pi, 10); %! assert (size (x1) == [1, 50] && abs (x1(1) - 10) < eps && abs (x1(50) - 100) < eps); %! assert (size (x2) == [1, 10] && abs (x2(1) - 10) < eps && abs (x2(10) - 100) < eps); %! assert (size (x3) == [1, 10] && abs (x3(1) - 10) < eps && abs (x3(10) - 0.01) < eps); %! assert (size (x4) == [1, 10] && abs (x4(1) - 10) < eps && abs (x4(10) - pi) < sqrt (eps)); ## Edge cases %!assert (logspace (Inf, Inf, 3), [Inf, Inf, Inf]) %!assert (logspace (-Inf, Inf, 3), [0, 1, Inf]) %!testif ; ! ismac () %! assert (logspace (Inf + 1i, Inf + 1i, 3), repmat (complex (-Inf,Inf), [1, 3])) %!testif ; ismac () <55538> %! assert (logspace (Inf + 1i, Inf + 1i, 3), repmat (complex (-Inf,Inf), [1, 3])) %!testif ; ! ismac () %! assert (logspace (-Inf + 1i, Inf + 1i, 3), [0, NaN + NaN * 1i, complex(-Inf, Inf)]) %!testif ; ismac () <55538> %! assert (logspace (-Inf + 1i, Inf + 1i, 3), [0, NaN + NaN * 1i, complex(-Inf, Inf)]) %!assert (logspace (0, Inf, 3), [1, Inf, Inf]) %!assert (logspace (0, -Inf, 3), [1, 0, 0]) %!assert (logspace (Inf, -Inf, 3), [Inf, 1, 0]) ## FIXME: These are bizarre corner cases for Matlab compatibility. See ## bug #56933. This is marked as "Won't Fix", but if linspace is updated at ## some point then these tests can be re-instated. ##%!assert (logspace (-Inf, 0, 3), [0, NaN, 1]) ##%!assert (logspace (Inf, 0, 3), [Inf, NaN, 1]) ## Test input validation %!error <Invalid call> logspace () %!error logspace ([1, 2; 3, 4], 5, 6) %!error logspace (1, [1, 2; 3, 4], 6) %!error logspace (1, 2, [1, 2; 3, 4])