| [ce133f] | 1 | /*
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| 2 | * Project: MoleCuilder
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| 3 | * Description: creates and alters molecular systems
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| 4 | * Copyright (C) 2010 University of Bonn. All rights reserved.
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| 5 | * Please see the LICENSE file or "Copyright notice" in builder.cpp for details.
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| 6 | */
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| 7 |
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| 8 | /**
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| [19bc74] | 9 | * \file randomnumbers.dox
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| [ce133f] | 10 | *
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| [19bc74] | 11 | * Created on: Oct 28, 2011
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| [ce133f] | 12 | * Author: heber
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| 13 | */
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| [750cff] | 14 |
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| 15 | /** \page randomnumbers Random Number Generation
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| 16 | *
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| 17 | * There is a factory for random number generators present. This implementation
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| 18 | * has been necessary due to lack of a common interface on the side of the
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| 19 | * boost::random programmer. Hence, we added a RandomNumberInterface for both
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| 20 | * engine and distribution and a factory for both and finally the conglomerate
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| 21 | * for combining both into a single RandomNumberGenerator.
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| 22 | *
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| 23 | * Whereever random numbers should be picked with a varying distribution or
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| 24 | * even better a user-controlled one, this RandomNumberGenerator should be
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| 25 | * used, e.g. as this
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| 26 | * \code
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| 27 | * RandomNumberGenerator &random = RandomNumberGeneratorFactory::getInstance().makeRandomNumberGenerator();
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| 28 | * const double rng_min = random.min();
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| 29 | * const double rng_max = random.max();
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| 30 | * \endcode
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| 31 | * This returns a reference to a random number generator instance. And also we obtain
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| 32 | * its RandomNumberGenerator::min() and RandomNumberGenerator::max() values.
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| 33 | * Then, we may create random values as simple as this:
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| 34 | * \code
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| 35 | * double random_value = (random()/((rng_max-rng_min)/2.) - 1.);
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| 36 | * \endcode
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| 37 | * which creates a random value within [-1,1]. Note that random() here is
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| 38 | * RandomNumberGenerator::operator() and not some global function.
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| 39 | *
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| 40 | * \note Do not necessarily use the random number generation when just a uniform
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| 41 | * distribution is required. The implementation is especially designed to allow
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| 42 | * the user control over the random number distribution. E.g. when filling the void
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| 43 | * space in a simulation box with molecules he may choose a discrete distribution
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| 44 | * with a small number of values to have a few, but random orientations of the
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| 45 | * molecules (MoleculeFillVoidWithMoleculeAction()).
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| 46 | *
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| 47 | * \date 2011-10-31
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| 48 | *
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| 49 | */
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