Ranlux64.cc
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Ranlux64.cc
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	/**
	* \authors The HEJ collaboration (see AUTHORS for details)
	* \date 2019
	* \copyright GPLv2 or later
	*/
	#include "HEJ/Ranlux64.hh"

	#include <cstdio>

	namespace HEJ {
	namespace {
	//! create Ranlux64Engine with state read from the given file
	CLHEP::Ranlux64Engine make_Ranlux64Engine(std::string const & seed_file) {
	CLHEP::Ranlux64Engine result;
	result.restoreStatus(seed_file.c_str());
	return result;
	}

	CLHEP::Ranlux64Engine make_Ranlux64Engine() {
	/*
	* some (all?) of the Ranlux64Engine constructors leave fields
	* uninitialised, invoking undefined behaviour. This can be
	* circumvented by restoring the state from a file
	*/
	static const std::string state =
	"9876\n"
	"0.91280703978419097666\n"
	"0.41606065829518357191\n"
	"0.99156342622341142601\n"
	"0.030922955274050423213\n"
	"0.16206278421638486975\n"
	"0.76151768001958330956\n"
	"0.43765760066092695979\n"
	"0.42904698253748563275\n"
	"0.11476317525663759511\n"
	"0.026620053590963976831\n"
	"0.65953715764414511114\n"
	"0.30136722624439826745\n"
	"3.5527136788005009294e-15 4\n"
	"1 202\n";

	std::FILE* tmpf = std::tmpfile();
	std::fputs(state.c_str(),tmpf);
	auto result = make_Ranlux64Engine("/proc/self/fd/"+std::to_string(fileno(tmpf)));
	return result;
	}
	}

	Ranlux64::Ranlux64(): ran_{make_Ranlux64Engine()} {}

	Ranlux64::Ranlux64(std::string const & seed_file):
	ran_{make_Ranlux64Engine(seed_file)}
	{}

	double Ranlux64::flat() {
	return ran_.flat();
	}
	}