/src/r-source/src/nmath/rchisq.c
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1 | | /* |
2 | | * Mathlib : A C Library of Special Functions |
3 | | * Copyright (C) 1998 Ross Ihaka |
4 | | * Copyright (C) 2000 The R Core Team |
5 | | * |
6 | | * This program is free software; you can redistribute it and/or modify |
7 | | * it under the terms of the GNU General Public License as published by |
8 | | * the Free Software Foundation; either version 2 of the License, or |
9 | | * (at your option) any later version. |
10 | | * |
11 | | * This program is distributed in the hope that it will be useful, |
12 | | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | | * GNU General Public License for more details. |
15 | | * |
16 | | * You should have received a copy of the GNU General Public License |
17 | | * along with this program; if not, a copy is available at |
18 | | * https://www.R-project.org/Licenses/ |
19 | | * |
20 | | * SYNOPSIS |
21 | | * |
22 | | * #include <Rmath.h> |
23 | | * double rchisq(double df); |
24 | | * |
25 | | * DESCRIPTION |
26 | | * |
27 | | * Random variates from the chi-squared distribution. |
28 | | * |
29 | | * NOTES |
30 | | * |
31 | | * Calls rgamma to do the real work. |
32 | | */ |
33 | | |
34 | | #include "nmath.h" |
35 | | |
36 | | double rchisq(double df) |
37 | 0 | { |
38 | 0 | if (!R_FINITE(df) || df < 0.0) ML_WARN_return_NAN; |
39 | |
|
40 | 0 | return rgamma(df / 2.0, 2.0); |
41 | 0 | } |