Mercurial > octave
view scripts/statistics/distributions/cauchy_pdf.m @ 3922:38c61cbf086c
[project @ 2002-05-01 06:48:35 by jwe]
author | jwe |
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date | Wed, 01 May 2002 06:48:36 +0000 |
parents | 434790acb067 |
children | 4b0f3b055331 |
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## Copyright (C) 1995, 1996, 1997 Kurt Hornik ## ## 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, 59 Temple Place - Suite 330, Boston, MA ## 02111-1307, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} cauchy_pdf (@var{x}, @var{lambda}, @var{sigma}) ## For each element of @var{x}, compute the probability density function ## (PDF) at @var{x} of the Cauchy distribution with location parameter ## @var{lambda} and scale parameter @var{sigma} > 0. Default values are ## @var{lambda} = 0, @var{sigma} = 1. ## @end deftypefn ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> ## Description: PDF of the Cauchy distribution function pdf = cauchy_pdf (x, location, scale) if (! (nargin == 1 || nargin == 3)) usage ("cauchy_pdf (x, lambda, sigma)"); endif if (nargin == 1) location = 0; scale = 1; endif [retval, x, location, scale] = common_size (x, location, scale); if (retval > 0) error ("cauchy_pdf: x, lambda and sigma must be of common size or scalar"); endif [r, c] = size (x); s = r * c; x = reshape (x, 1, s); location = reshape (location, 1, s); scale = reshape (scale, 1, s); pdf = NaN * ones (1, s); k = find ((x > -Inf) & (x < Inf) & (location > -Inf) & (location < Inf) & (scale > 0) & (scale < Inf)); if (any (k)) pdf(k) = ((1 ./ (1 + ((x(k) - location(k)) ./ scale(k)) .^ 2)) / pi ./ scale(k)); endif pdf = reshape (pdf, r, c); endfunction