Mercurial > octave
view scripts/general/logspace.m @ 245:16a24e76d6e0
[project @ 1993-12-03 02:00:15 by jwe]
author | jwe |
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date | Fri, 03 Dec 1993 02:00:15 +0000 |
parents | b4df021f796c |
children | 0ce34c2fc3d5 |
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# Copyright (C) 1993 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 2, 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, write to the Free # Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. function retval = logspace (x1, x2, n) # usage: logspace (x1, x2, n) # # Return a vector of n logarithmically equally spaced points between # x1 and x2 inclusive. # # If the final argument is omitted, n = 50 is assumed. # # All three arguments must be scalars. # # Note that if if x2 is pi, the points are between 10^x1 and pi, NOT # 10^x1 and 10^pi. # # Yes, this is pretty stupid, because you could achieve the same # result with logspace (x1, log10 (pi)), but Matlab does this, and # claims that is useful for signal processing applications. # # See also: linspace if (nargin == 2) npoints = 50; elseif (nargin == 3) if (length (n) == 1) npoints = n; else error ("logspace: arguments must be scalars"); endif else error ("usage: logspace (x1, x2 [, n])"); endif if (npoints < 2) error ("logspace: npoints must be greater than 2"); endif if (length (x1) == 1 && length (x2) == 1) x2_tmp = x2; if (x2 == pi) x2_tmp = log10 (pi); endif retval = linspace (x1, x2_tmp, npoints); for i = 1:npoints retval(i) = 10 ^ retval(i); endfor else error ("logspace: arguments must be scalars"); endif endfunction