Mercurial > octave
comparison scripts/statistics/distributions/exponential_pdf.m @ 3426:f8dde1807dee
[project @ 2000-01-13 08:40:00 by jwe]
author | jwe |
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date | Thu, 13 Jan 2000 08:40:53 +0000 |
parents | e4f4b2d26ee9 |
children | 434790acb067 |
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3425:8625164a0a39 | 3426:f8dde1807dee |
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1 ## Copyright (C) 1995, 1996, 1997 Kurt Hornik | 1 ## Copyright (C) 1995, 1996, 1997 Kurt Hornik |
2 ## | 2 ## |
3 ## This program is free software; you can redistribute it and/or modify | 3 ## This program is free software; you can redistribute it and/or modify |
4 ## it under the terms of the GNU General Public License as published by | 4 ## it under the terms of the GNU General Public License as published by |
5 ## the Free Software Foundation; either version 2, or (at your option) | 5 ## the Free Software Foundation; either version 2, or (at your option) |
6 ## any later version. | 6 ## any later version. |
7 ## | 7 ## |
8 ## This program is distributed in the hope that it will be useful, but | 8 ## This program is distributed in the hope that it will be useful, but |
9 ## WITHOUT ANY WARRANTY; without even the implied warranty of | 9 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | 10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
11 ## General Public License for more details. | 11 ## General Public License for more details. |
12 ## | 12 ## |
13 ## You should have received a copy of the GNU General Public License | 13 ## You should have received a copy of the GNU General Public License |
14 ## along with this file. If not, write to the Free Software Foundation, | 14 ## along with this file. If not, write to the Free Software Foundation, |
15 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | 15 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
16 | 16 |
17 ## usage: exponential_pdf (x, lambda) | 17 ## usage: exponential_pdf (x, lambda) |
21 | 21 |
22 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> | 22 ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> |
23 ## Description: PDF of the exponential distribution | 23 ## Description: PDF of the exponential distribution |
24 | 24 |
25 function pdf = exponential_pdf (x, l) | 25 function pdf = exponential_pdf (x, l) |
26 | 26 |
27 if (nargin != 2) | 27 if (nargin != 2) |
28 usage ("exponential_pdf (x, lambda)"); | 28 usage ("exponential_pdf (x, lambda)"); |
29 endif | 29 endif |
30 | 30 |
31 [retval, x, l] = common_size (x, l); | 31 [retval, x, l] = common_size (x, l); |
32 if (retval > 0) | 32 if (retval > 0) |
33 error (["exponential_pdf: ", ... | 33 error (["exponential_pdf: ", ... |
34 "x and lambda must be of common size or scalar"]); | 34 "x and lambda must be of common size or scalar"]); |
35 endif | 35 endif |
36 | 36 |
37 [r, c] = size (x); | 37 [r, c] = size (x); |
38 s = r * c; | 38 s = r * c; |
39 x = reshape (x, 1, s); | 39 x = reshape (x, 1, s); |
42 | 42 |
43 k = find (!(l > 0) | isnan (x)); | 43 k = find (!(l > 0) | isnan (x)); |
44 if any (k) | 44 if any (k) |
45 pdf(k) = NaN * ones (1, length (k)); | 45 pdf(k) = NaN * ones (1, length (k)); |
46 endif | 46 endif |
47 | 47 |
48 k = find ((x > 0) & (x < Inf) & (l > 0)); | 48 k = find ((x > 0) & (x < Inf) & (l > 0)); |
49 if any (k) | 49 if any (k) |
50 pdf(k) = l(k) .* exp (- l(k) .* x(k)); | 50 pdf(k) = l(k) .* exp (- l(k) .* x(k)); |
51 endif | 51 endif |
52 | 52 |
53 pdf = reshape (pdf, r, c); | 53 pdf = reshape (pdf, r, c); |
54 | 54 |
55 endfunction | 55 endfunction |