update packages

[CreaPhase.git] / octave_packages / m / general / logspace.m

diff --git a/octave_packages/m/general/logspace.m b/octave_packages/m/general/logspace.m
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+## Copyright (C) 1993-2012 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} {} logspace (@var{a}, @var{b})
+## @deftypefnx {Function File} {} logspace (@var{a}, @var{b}, @var{n})
+## @deftypefnx {Function File} {} 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 second argument @var{b}
+## if fewer than two values are requested.
+## @seealso{linspace}
+## @end deftypefn
+
+## Author: jwe
+
+function retval = logspace (base, limit, n = 50)
+
+  if (nargin != 2 && nargin != 3)
+    print_usage ();
+  endif
+
+  if (! (isscalar (base) && isscalar (limit) && isscalar (n)))
+    error ("logspace: arguments BASE, LIMIT, and N must be scalars");
+  endif
+
+  npoints = fix (n);
+
+  if (limit == pi)
+    limit = log10 (pi);
+  endif
+
+  retval = 10 .^ (linspace (base, limit, 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] && x1(1) == 10 && x1(50) == 100);
+%! assert (size (x2) == [1, 10] && x2(1) == 10 && x2(10) == 100);
+%! assert (size (x3) == [1, 10] && x3(1) == 10 && x3(10) == 0.01);
+%! assert (size (x4) == [1, 10] && x4(1) == 10 && abs (x4(10) - pi) < sqrt (eps));
+
+%% Test input validation
+%!error logspace ();
+%!error logspace (1, 2, 3, 4);
+%!error logspace ([1, 2; 3, 4], 5, 6);
+%!error logspace (1, [1, 2; 3, 4], 6);
+%!error logspace (1, 2, [1, 2; 3, 4]);
+