From 9c3e819f066acaf9f5a416630fa7dd83fdc2539d Mon Sep 17 00:00:00 2001 From: Thomas Arnhold Date: Tue, 13 May 2014 08:42:21 +0200 Subject: move boost rng wrapper from sc to comphelper so we can re-use it in other modules Change-Id: I6057b1e955f745019fd48f91a754279df0f2b948 Reviewed-on: https://gerrit.libreoffice.org/9348 Reviewed-by: Thomas Arnhold Tested-by: Thomas Arnhold --- comphelper/source/misc/random.cxx | 54 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 comphelper/source/misc/random.cxx (limited to 'comphelper/source') diff --git a/comphelper/source/misc/random.cxx b/comphelper/source/misc/random.cxx new file mode 100644 index 000000000000..a97608649bbf --- /dev/null +++ b/comphelper/source/misc/random.cxx @@ -0,0 +1,54 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * Contributor(s): + * Copyright (C) 2012 Tino Kluge + */ + +#include + +#include + +// this is nothing but a simple wrapper around +// the boost random generators + +namespace comphelper +{ +namespace rng +{ + +// underlying random number generator +// boost::mt19937 implements the Mersenne twister algorithm which +// is fast and has good statistical properties, it produces integers +// in the range of [0, 2^32-1] internally +// memory requirement: 625*sizeof(uint32_t) +// http://en.wikipedia.org/wiki/Mersenne_twister +#define BOOST_RNG_ALGO boost::mt19937 +BOOST_RNG_ALGO global_rng; + +// initialises the state of the global random number generator +// should only be called once at the start of the main programme +// (note, a few boost::variate_generator<> (like normal) have their +// own state which would need a reset as well to guarantee identical +// sequence of numbers, e.g. via myrand.distribution().reset()) +void seed(int i) +{ + global_rng.seed(i); +} + +// uniform [0,1) or [a,b) distribution +double uniform() +{ + static boost::uniform_01 myrand(global_rng); + return myrand(); +} + +} // namespace +} // namespace + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ -- cgit