octave:scripts/statistics/distributions/wblrnd.m

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scripts/statistics/distributions/wblrnd.m

changeset 10289:	4b124317dc38
parent:	1bf0ce0930be
author:	John W. Eaton <jwe@octave.org>
date:	Tue Feb 09 20:58:55 2010 -0500 (72 minutes ago)
permissions:	-rw-r--r--
description:	base_properties::set_children: account for hidden children
     1## Copyright (C) 1995, 1996, 1997, 2006, 2007, 2009 Kurt Hornik
     2##
     3## This file is part of Octave.
     4##
     5## Octave is free software; you can redistribute it and/or modify it
     6## under the terms of the GNU General Public License as published by
     7## the Free Software Foundation; either version 3 of the License, or (at
     8## your option) any later version.
     9##
    10## Octave is distributed in the hope that it will be useful, but
    11## WITHOUT ANY WARRANTY; without even the implied warranty of
    12## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13## General Public License for more details.
    14##
    15## You should have received a copy of the GNU General Public License
    16## along with Octave; see the file COPYING.  If not, see
    17## <http://www.gnu.org/licenses/>.
    18
    19## -*- texinfo -*-
    20## @deftypefn {Function File} {} wblrnd (@var{scale}, @var{shape}, @var{r}, @var{c})
    21## @deftypefnx {Function File} {} wblrnd (@var{scale}, @var{shape}, @var{sz})
    22## Return an @var{r} by @var{c} matrix of random samples from the
    23## Weibull distribution with parameters @var{scale} and @var{shape}
    24## which must be scalar or of size @var{r} by @var{c}.  Or if @var{sz}
    25## is a vector return a matrix of size @var{sz}.
    26##
    27## If @var{r} and @var{c} are omitted, the size of the result matrix is
    28## the common size of @var{alpha} and @var{sigma}.
    29## @end deftypefn
    30
    31## Author: KH <Kurt.Hornik@wu-wien.ac.at>
    32## Description: Random deviates from the Weibull distribution
    33
    34function rnd = wblrnd (scale, shape, r, c)
    35
    36  if (nargin > 1)
    37    if (!isscalar(shape) || !isscalar(scale)) 
    38      [retval, shape, scale] = common_size (shape, scale);
    39      if (retval > 0)
    40	error ("wblrnd: shape and scale must be of common size or scalar");
    41      endif
    42    endif
    43  endif
    44
    45  if (nargin == 4)
    46    if (! (isscalar (r) && (r > 0) && (r == round (r))))
    47      error ("wblrnd: r must be a positive integer");
    48    endif
    49    if (! (isscalar (c) && (c > 0) && (c == round (c))))
    50      error ("wblrnd: c must be a positive integer");
    51    endif
    52    sz = [r, c];
    53
    54    if (any (size (scale) != 1) && 
    55	((length (size (scale)) != length (sz))
    56	 || any (size (scale) != sz)))
    57      error ("wblrnd: shape and scale must be scalar or of size [r, c]");
    58    endif
    59  elseif (nargin == 3)
    60    if (isscalar (r) && (r > 0))
    61      sz = [r, r];
    62    elseif (isvector(r) && all (r > 0))
    63      sz = r(:)';
    64    else
    65      error ("wblrnd: r must be a positive integer or vector");
    66    endif
    67
    68    if (any (size (scale) != 1) && 
    69	((length (size (scale)) != length (sz))
    70	 || any (size (scale) != sz)))
    71      error ("wblrnd: shape and scale must be scalar or of size sz");
    72    endif
    73  elseif (nargin == 2)
    74    sz = size(shape);
    75  else
    76    print_usage ();
    77  endif
    78
    79  if (isscalar (shape) && isscalar (scale))
    80    if ((shape > 0) & (shape < Inf) & (scale > 0) & (scale < Inf))
    81      rnd = scale .* rande(sz) .^ (1./shape);
    82    else
    83      rnd = NaN * ones (sz);
    84    endif
    85  else
    86    rnd = scale .* rande(sz) .^ (1./shape);
    87    k = find ((shape <= 0) | (shape == Inf) | ((scale <= 0) & (scale == Inf)));
    88    if (any(k))
    89      rnd(k) = NaN;
    90    endif
    91  endif
    92
    93endfunction
    94