|
5410
|
1 ## Copyright (C) 1995, 1996, 1997 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 2, or (at your option) |
|
|
8 ## 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, write to the Free |
|
|
17 ## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
|
|
18 ## 02110-1301, USA. |
|
|
19 |
|
|
20 ## -*- texinfo -*- |
|
|
21 ## @deftypefn {Function File} {} geometric_inv (@var{x}, @var{p}) |
|
|
22 ## For each element of @var{x}, compute the quantile at @var{x} of the |
|
|
23 ## geometric distribution with parameter @var{p}. |
|
|
24 ## @end deftypefn |
|
|
25 |
|
|
26 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> |
|
|
27 ## Description: Quantile function of the geometric distribution |
|
|
28 |
|
|
29 function inv = geometric_inv (x, p) |
|
|
30 |
|
|
31 if (nargin != 2) |
|
|
32 usage ("geometric_inv (x, p)"); |
|
|
33 endif |
|
|
34 |
|
|
35 if (!isscalar (x) && !isscalar (p)) |
|
|
36 [retval, x, p] = common_size (x, p); |
|
|
37 if (retval > 0) |
|
|
38 error ("geometric_inv: x and p must be of common size or scalar"); |
|
|
39 endif |
|
|
40 endif |
|
|
41 |
|
|
42 inv = zeros (size (x)); |
|
|
43 |
|
|
44 k = find (!(x >= 0) | !(x <= 1) | !(p >= 0) | !(p <= 1)); |
|
|
45 if (any (k)) |
|
|
46 inv(k) = NaN; |
|
|
47 endif |
|
|
48 |
|
|
49 k = find ((x == 1) & (p >= 0) & (p <= 1)); |
|
|
50 if (any (k)) |
|
|
51 inv(k) = Inf; |
|
|
52 endif |
|
|
53 |
|
|
54 k = find ((x > 0) & (x < 1) & (p > 0) & (p <= 1)); |
|
|
55 if (any (k)) |
|
|
56 if (isscalar (x)) |
|
|
57 inv(k) = max (ceil (log (1 - x) ./ log (1 - p(k))) - 1, 0); |
|
|
58 elseif (isscalar (p)) |
|
|
59 inv(k) = max (ceil (log (1 - x(k)) / log (1 - p)) - 1, 0); |
|
|
60 else |
|
|
61 inv(k) = max (ceil (log (1 - x(k)) ./ log (1 - p(k))) - 1, 0); |
|
|
62 endif |
|
|
63 endif |
|
|
64 |
|
|
65 endfunction |
