Rcpp Version 0.12.12
rf.h
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1 // -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; indent-tabs-mode: nil; -*-
2 //
3 // rf.h: Rcpp R/C++ interface class library --
4 //
5 // Copyright (C) 2010 - 2016 Douglas Bates, Dirk Eddelbuettel and Romain Francois
6 //
7 // This file is part of Rcpp.
8 //
9 // Rcpp is free software: you can redistribute it and/or modify it
10 // under the terms of the GNU General Public License as published by
11 // the Free Software Foundation, either version 2 of the License, or
12 // (at your option) any later version.
13 //
14 // Rcpp is distributed in the hope that it will be useful, but
15 // WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
18 //
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20 // along with Rcpp. If not, see <http://www.gnu.org/licenses/>.
21 
22 #ifndef Rcpp__stats__random_rf_h
23 #define Rcpp__stats__random_rf_h
24 
25 namespace Rcpp {
26 namespace stats {
27 
29 public:
30 
31  FGenerator_Finite_Finite( double n1_, double n2_ ) :
32  n1__2(n1_ / 2.0 ), n2__2(n2_ / 2.0 ), ratio(n2_/n1_) {}
33 
34  inline double operator()() const {
35  // here we know that both n1 and n2 are finite
36  // return ( ::rchisq( n1 ) / n1 ) / ( ::rchisq( n2 ) / n2 );
37  return ratio * ::Rf_rgamma( n1__2, 2.0 ) / ::Rf_rgamma( n2__2, 2.0 ) ;
38  }
39 
40 private:
41  double n1__2, n2__2, ratio ;
42 };
43 
45 public:
46 
47  FGenerator_NotFinite_Finite( double n2_ ) : n2( n2_), n2__2(n2_ / 2.0 ) {}
48 
49  inline double operator()() const {
50  // return n2 / ::rchisq( n2 ) ;
51  return n2 / ::Rf_rgamma( n2__2, 2.0 ) ;
52  }
53 
54 private:
55  double n2, n2__2 ;
56 };
57 
59 public:
60 
61  FGenerator_Finite_NotFinite( double n1_ ) : n1(n1_), n1__2(n1_ / 2.0 ) {}
62 
63  inline double operator()() const {
64  // return ::rchisq( n1 ) / n1 ;
65  return ::Rf_rgamma( n1__2, 2.0 ) / n1 ;
66  }
67 
68 private:
69  double n1, n1__2 ;
70 };
71 
72 } // stats
73 } // Rcpp
74 
75 #endif
FGenerator_Finite_Finite(double n1_, double n2_)
Definition: rf.h:31
FGenerator_NotFinite_Finite(double n2_)
Definition: rf.h:47
double operator()() const
Definition: rf.h:34
Rcpp API.
Definition: algo.h:28
FGenerator_Finite_NotFinite(double n1_)
Definition: rf.h:61