Mercurial > hg > octave-nkf
annotate scripts/statistics/distributions/wblinv.m @ 10525:3306cfcb856e
Replace constructs like "NaN * one()" with "NaN()" and "Inf * ones ()" with "Inf()"
| author | David Bateman <dbateman@free.fr> |
|---|---|
| date | Fri, 16 Apr 2010 10:32:07 +0200 |
| parents | a1dbe9d80eee |
| children | 9cb5c0b7b43b |
| rev | line source |
|---|---|
| 7017 | 1 ## Copyright (C) 1995, 1996, 1997, 2006, 2007 Kurt Hornik |
| 5693 | 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 | |
| 7016 | 7 ## the Free Software Foundation; either version 3 of the License, or (at |
| 8 ## your option) any later version. | |
| 5693 | 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 | |
| 7016 | 16 ## along with Octave; see the file COPYING. If not, see |
| 17 ## <http://www.gnu.org/licenses/>. | |
| 5693 | 18 |
| 19 ## -*- texinfo -*- | |
| 20 ## @deftypefn {Function File} {} wblinv (@var{x}, @var{scale}, @var{shape}) | |
| 21 ## Compute the quantile (the inverse of the CDF) at @var{x} of the | |
| 22 ## Weibull distribution with shape parameter @var{scale} and scale | |
| 23 ## parameter @var{shape}. | |
| 24 ## @end deftypefn | |
| 25 | |
| 26 ## Author: KH <Kurt.Hornik@wu-wien.ac.at> | |
| 27 ## Description: Quantile function of the Weibull distribution | |
| 28 | |
| 29 function inv = wblinv (x, scale, shape) | |
| 30 | |
| 31 if (nargin < 1 || nargin > 3) | |
| 6046 | 32 print_usage (); |
| 5693 | 33 endif |
| 34 | |
| 35 if (nargin < 3) | |
| 36 shape = 1; | |
| 37 endif | |
| 38 | |
| 39 if (nargin < 2) | |
| 40 scale = 1; | |
| 41 endif | |
| 42 | |
| 43 if (!isscalar (shape) || !isscalar (scale)) | |
| 44 [retval, x, shape, scale] = common_size (x, shape, scale); | |
| 45 if (retval > 0) | |
| 46 error ("wblinv: x, scale and shape must be of common size or scalar"); | |
| 47 endif | |
| 48 endif | |
| 49 | |
|
10525
3306cfcb856e
Replace constructs like "NaN * one()" with "NaN()" and "Inf * ones ()" with "Inf()"
David Bateman <dbateman@free.fr>
parents:
7017
diff
changeset
|
50 inv = NaN (size (x)); |
| 5693 | 51 |
| 52 ok = ((shape > 0) & (shape < Inf) & (scale > 0) & (scale < Inf)); | |
| 53 | |
| 54 k = find ((x == 0) & ok); | |
| 55 if (any (k)) | |
| 56 inv(k) = -Inf; | |
| 57 endif | |
| 58 | |
| 59 k = find ((x > 0) & (x < 1) & ok); | |
| 60 if (any (k)) | |
| 61 if (isscalar (shape) && isscalar (scale)) | |
| 62 inv(k) = scale * (- log (1 - x(k))) .^ (1 / shape); | |
| 63 else | |
| 64 inv(k) = scale(k) .* (- log (1 - x(k))) .^ (1 ./ shape(k)); | |
| 65 endif | |
| 66 endif | |
| 67 | |
| 68 k = find ((x == 1) & ok); | |
| 69 if (any (k)) | |
| 70 inv(k) = Inf; | |
| 71 endif | |
| 72 | |
| 73 endfunction |