fe372028dc
Added llformat_to_utf8 Added LLProcessLauncher::getExecutable() LLStringTableEntry() ctor and dtor definitions moved from .h to .cpp (should be safe)
134 lines
3.9 KiB
C
134 lines
3.9 KiB
C
/**
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* @file llrand.h
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* @brief Information, functions, and typedefs for randomness.
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*
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* $LicenseInfo:firstyear=2000&license=viewergpl$
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*
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* Copyright (c) 2000-2009, Linden Research, Inc.
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*
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* Second Life Viewer Source Code
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* The source code in this file ("Source Code") is provided by Linden Lab
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* to you under the terms of the GNU General Public License, version 2.0
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* ("GPL"), unless you have obtained a separate licensing agreement
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* ("Other License"), formally executed by you and Linden Lab. Terms of
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* the GPL can be found in doc/GPL-license.txt in this distribution, or
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* online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
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*
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* There are special exceptions to the terms and conditions of the GPL as
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* it is applied to this Source Code. View the full text of the exception
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* in the file doc/FLOSS-exception.txt in this software distribution, or
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* online at
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* http://secondlifegrid.net/programs/open_source/licensing/flossexception
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*
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* By copying, modifying or distributing this software, you acknowledge
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* that you have read and understood your obligations described above,
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* and agree to abide by those obligations.
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*
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* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
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* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
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* COMPLETENESS OR PERFORMANCE.
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* $/LicenseInfo$
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*/
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#ifndef LL_LLRAND_H
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#define LL_LLRAND_H
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#include <boost/random/lagged_fibonacci.hpp>
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#include <boost/random/mersenne_twister.hpp>
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/**
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* Use the boost random number generators if you want a stateful
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* random numbers. If you want more random numbers, use the
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* c-functions since they will generate faster/better randomness
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* across the process.
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*
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* I tested some of the boost random engines, and picked a good double
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* generator and a good integer generator. I also took some timings
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* for them on linux using gcc 3.3.5. The harness also did some other
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* fairly trivial operations to try to limit compiler optimizations,
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* so these numbers are only good for relative comparisons.
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*
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* usec/inter algorithm
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* 0.21 boost::minstd_rand0
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* 0.039 boost:lagged_fibonacci19937
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* 0.036 boost:lagged_fibonacci607
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* 0.44 boost::hellekalek1995
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* 0.44 boost::ecuyer1988
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* 0.042 boost::rand48
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* 0.043 boost::mt11213b
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* 0.028 stdlib random()
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* 0.05 stdlib lrand48()
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* 0.034 stdlib rand()
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* 0.020 the old & lame LLRand
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*/
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/**
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*@brief Generate a float from [0, RAND_MAX).
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*/
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S32 LL_COMMON_API ll_rand();
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/**
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*@brief Generate a float from [0, val) or (val, 0].
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*/
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S32 LL_COMMON_API ll_rand(S32 val);
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/**
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*@brief Generate a float from [0, 1.0).
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*/
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F32 LL_COMMON_API ll_frand();
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/**
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*@brief Generate a float from [0, val) or (val, 0].
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*/
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F32 LL_COMMON_API ll_frand(F32 val);
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/**
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*@brief Generate a double from [0, 1.0).
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*/
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F64 LL_COMMON_API ll_drand();
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/**
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*@brief Generate a double from [0, val) or (val, 0].
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*/
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F64 LL_COMMON_API ll_drand(F64 val);
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/**
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* @brief typedefs for good boost lagged fibonacci.
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* @see boost::lagged_fibonacci
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*
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* These generators will quickly generate doubles. Note the memory
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* requirements, because they are somewhat high. I chose the smallest
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* one, and one comparable in speed but higher periodicity without
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* outrageous memory requirements.
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* To use:
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* LLRandLagFib607 foo((U32)time(NULL));
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* double bar = foo();
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*/
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typedef boost::lagged_fibonacci607 LLRandLagFib607;
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/**<
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* lengh of cycle: 2^32,000
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* memory: 607*sizeof(double) (about 5K)
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*/
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typedef boost::lagged_fibonacci2281 LLRandLagFib2281;
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/**<
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* lengh of cycle: 2^120,000
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* memory: 2281*sizeof(double) (about 17K)
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*/
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/**
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* @breif typedefs for a good boost mersenne twister implementation.
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* @see boost::mersenne_twister
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*
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* This fairly quickly generates U32 values
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* To use:
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* LLRandMT19937 foo((U32)time(NULL));
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* U32 bar = foo();
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*
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* lengh of cycle: 2^19,937-1
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* memory: about 2496 bytes
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*/
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typedef boost::mt11213b LLRandMT19937;
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#endif
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