Re: statistics distributions function names

[Ben Barrowes]

For example octave's weibull_rnd.m, a new file named weibrnd.m could be 
placed in the
statistics/distributions
directory containing the text of weibull_rnd.m except for the name change:

## 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
## 02110-1301, USA.

## -*- texinfo -*-
## @deftypefn {Function File} {} weibrnd (@var{alpha}, @var{sigma}, 
@var{r}, @var{c})
## @deftypefnx {Function File} {} weibrnd (@var{alpha}, @var{sigma}, 
@var{sz})
## Return an @var{r} by @var{c} matrix of random samples from the
## Weibull distribution with parameters @var{alpha} and @var{sigma}
## which must be scalar or of size @var{r} by @var{c}. Or if @var{sz}
## is a vector return a matrix of size @var{sz}.
##
## If @var{r} and @var{c} are omitted, the size of the result matrix is
## the common size of @var{alpha} and @var{sigma}.
## @end deftypefn

## Author: KH <address@hidden>
## Description: Random deviates from the Weibull distribution

function rnd = weibrnd (shape, scale, r, c)

 if (nargin > 1)
   if (!isscalar(shape) || !isscalar(scale))
     [retval, shape, scale] = common_size (shape, scale);
     if (retval > 0)
   error ("weibrnd: shape and scale must be of common size or scalar");
     endif
   endif
 endif

 if (nargin == 4)
   if (! (isscalar (r) && (r > 0) && (r == round (r))))
     error ("weibrnd: r must be a positive integer");
   endif
   if (! (isscalar (c) && (c > 0) && (c == round (c))))
     error ("weibrnd: c must be a positive integer");
   endif
   sz = [r, c];

   if (any (size (scale) != 1) &&
   ((length (size (scale)) != length (sz)) ||
    any (size (scale) != sz)))
     error ("weilbull_rnd: shape and scale must be scalar or of size 
[r, c]");
   endif
 elseif (nargin == 3)
   if (isscalar (r) && (r > 0))
     sz = [r, r];
   elseif (isvector(r) && all (r > 0))
     sz = r(:)';
   else
     error ("weibrnd: r must be a postive integer or vector");
   endif

   if (any (size (scale) != 1) &&
   ((length (size (scale)) != length (sz)) ||
    any (size (scale) != sz)))
     error ("weibrnd: shape and scale must be scalar or of size sz");
   endif
 elseif (nargin == 2)
   sz = size(shape);
 else
   usage ("weibrnd (alpha, sigma, r, c)");
 endif

 if (isscalar (shape) && isscalar (scale))
   if ((shape > 0) & (shape < Inf) & (scale > 0) & (scale < Inf))
     rnd = (scale * (- log (1 - rand (sz))) .^ (1 / shape));
   else
     rnd = NaN * ones (sz);
   endif
 else
   rnd = NaN * ones (sz);
   k = find ((shape > 0) & (shape < Inf) & (scale > 0) & (scale < Inf));
   if (any (k))
     rnd(k) = (scale(k)
       .* (- log (1 - rand (size (k)))) .^ (1 ./ shape(k)));
   endif
 endif

endfunction


The following patch adds a depreciation warning in weibull_rnd.m:

*** 
/usr/local/share/octave/2.9.3/m/statistics/distributions/weibull_rnd.m      
2005-06-01 14:07:16.000000000 -0600
--- weibull_rnd.m       2005-07-01 12:16:05.000000000 -0600
***************
*** 34,39 ****
--- 34,41 ----

 function rnd = weibull_rnd (shape, scale, r, c)

+   warning('weibull_rnd is being depreciaited in favor of weibrnd')
+
   if (nargin > 1)
     if (!isscalar(shape) || !isscalar(scale))
       [retval, shape, scale] = common_size (shape, scale);



This approach is simple, but should work for most of the statistics 
function now located in statistics/distributions.
Let me know if this is acceptable and I will send other similar modified 
files to you as I get the chance.

Note that I couldn't find any other function in the octave distribution 
that referenced weibull_rnd.m, so no other trunk functions needs to be 
changed.

bb



John W. Eaton wrote:

> On 23-Jun-2005, Ben Barrowes wrote:
>
> | Why are the names for the distribution functions in
> | /usr/local/share/octave/2.9.3/m/statistics/distributions/
> | different from their ML counterparts?
>
> I'm not certain, but it might be that some of the Octave functions
> were written before the functions in Matlab.  Or, it might be that
> they were written at a time when there was not so much empasis on
> compatibility with Matlab.
>
> If you owuld like for this to improve, then please submit patches to
> provide a compatibile interface.  It would be best to keep the current
> interface at least for a while, perhaps also having the incompatible
> functions emit warnings.
>
> jwe
>
>
>
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