Mercurial > octave
view scripts/general/logspace.m @ 33577:2506c2d30b32 bytecode-interpreter tip
maint: Merge default to bytecode-interpreter
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Sat, 11 May 2024 18:49:01 -0400 |
parents | 2e484f9f1f18 |
children |
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######################################################################## ## ## Copyright (C) 1993-2024 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{y} =} logspace (@var{a}, @var{b}) ## @deftypefnx {} {@var{y} =} logspace (@var{a}, @var{b}, @var{n}) ## @deftypefnx {} {@var{y} =} logspace (@var{a}, pi) ## @deftypefnx {} {@var{y} =} 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 the number of elements @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 ## which is useful in digital signal processing. ## ## Programming Notes: 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 a single value (@var{n} = 1) is requested. ## If @var{n} is not an integer then @code{floor (@var{n})} is used to round ## the number of elements. If @var{n} is zero or negative then an empty 1x0 ## matrix is returned. ## @seealso{linspace} ## @end deftypefn function y = 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 y = 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]); %! assert (abs (x1(1) - 10) < eps); %! assert (abs (x1(50) - 100) < eps); %! assert (size (x2) == [1, 10]); %! assert (abs (x2(1) - 10) < eps); %! assert (abs (x2(10) - 100) < eps); %! assert (size (x3) == [1, 10]); %! assert (abs (x3(1) - 10) < eps); %! assert (abs (x3(10) - 0.01) < eps); %! assert (size (x4) == [1, 10]); %! assert (abs (x4(1) - 10) < eps); %! assert (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 ; ! __have_feature__ ("LLVM_LIBCXX") %! assert (logspace (Inf + 1i, Inf + 1i, 3), %! repmat (complex (-Inf,Inf), [1, 3])) %!testif HAVE_LLVM_LIBCXX <55538> %! assert (logspace (Inf + 1i, Inf + 1i, 3), %! repmat (complex (-Inf,Inf), [1, 3])) %!testif ; ! __have_feature__ ("LLVM_LIBCXX") %! assert (logspace (-Inf + 1i, Inf + 1i, 3), %! [0, NaN + NaN * 1i, complex(-Inf, Inf)]) %!testif HAVE_LLVM_LIBCXX <55538> %! assert (logspace (-Inf + 1i, Inf + 1i, 3), %! [0, NaN + NaN * 1i, complex(-Inf, Inf)]) ## Octave prefers to return NaN which indicates failure of algorithm. ## Tests can be re-instated if full Matlab-compatibility is coded. %!#assert (logspace (0, Inf, 3), [1, Inf, Inf]) %!#assert (logspace (0, -Inf, 3), [1, 0, 0]) %!assert (logspace (Inf, -Inf, 3), [Inf, 1, 0]) %!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])