rlogis.h

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// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; tab-width: 4 -*-
//
// rlogis.h: Rcpp R/C++ interface class library -- 
//
// Copyright (C) 2010 - 2011 Douglas Bates, Dirk Eddelbuettel and Romain Francois
//
// This file is part of Rcpp.
//
// Rcpp is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// Rcpp is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Rcpp.  If not, see <http://www.gnu.org/licenses/>.

#ifndef Rcpp__stats__random_rlogis_h
#define Rcpp__stats__random_rlogis_h

namespace Rcpp {
        namespace stats {

                class LogisGenerator : public ::Rcpp::Generator<false,double> {
                public:
        
                        LogisGenerator( double location_, double scale_ ) : 
                                location(location_), scale(scale_) {}
        
                        inline double operator()() const {
                                double u = unif_rand() ;
                                return location + scale * ::log(u / (1. - u));
                        }
        
                private:
                        double location ;
                        double scale ;
                } ;

                class LogisGenerator_1 : public ::Rcpp::Generator<false,double> {
                public:
        
                        LogisGenerator_1( double location_) : 
                                location(location_) {}
        
                        inline double operator()() const {
                                double u = unif_rand() ;
                                return location + ::log(u / (1. - u));
                        }
        
                private:
                        double location ;
                } ;

                class LogisGenerator_0 : public ::Rcpp::Generator<false,double> {
                public:
        
                        LogisGenerator_0() {}
        
                        inline double operator()() const {
                                double u = unif_rand() ;
                                return ::log(u / (1. - u));
                        }

                } ;

        } // stats

        // Please make sure you to read Section 6.3 of "Writing R Extensions"
        // about the need to call GetRNGstate() and PutRNGstate() when using 
        // the random number generators provided by R.
        inline NumericVector rlogis( int n, double location, double scale ){
                if (ISNAN(location) || !R_FINITE(scale))
                        return NumericVector( n, R_NaN ) ;

                if (scale == 0. || !R_FINITE(location))
                        return NumericVector( n, location );
    
                return NumericVector( n, stats::LogisGenerator( location, scale ) ) ;
        }

        // Please make sure you to read Section 6.3 of "Writing R Extensions"
        // about the need to call GetRNGstate() and PutRNGstate() when using 
        // the random number generators provided by R.
        inline NumericVector rlogis( int n, double location /*, double scale =1.0 */ ){
                if (ISNAN(location) )
                        return NumericVector( n, R_NaN ) ;

                if (!R_FINITE(location))
                        return NumericVector( n, location );
    
                return NumericVector( n, stats::LogisGenerator_1( location ) ) ;
        }

        // Please make sure you to read Section 6.3 of "Writing R Extensions"
        // about the need to call GetRNGstate() and PutRNGstate() when using 
        // the random number generators provided by R.
        inline NumericVector rlogis( int n /*, double location [=0.0], double scale =1.0 */ ){
                return NumericVector( n, stats::LogisGenerator_0() ) ;
        }

} // Rcpp

#endif