155 lines
4.6 KiB
C++
155 lines
4.6 KiB
C++
/* -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
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-----------------------------------------------------------------------------
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eoUniformInit.h
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(c) Maarten Keijzer, GeNeura Team, Marc Schoenauer, 1999 - 2002
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Contact: todos@geneura.ugr.es, http://geneura.ugr.es
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Marc.Schoenauer@inria.fr
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*/
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//-----------------------------------------------------------------------------
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/** Copied from the eoRndGenerators to have objects deriving from eoInit
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* As the whole initialization mechanism in EO is based on eoInit rather than
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* eoRndGenerators, we might as well have these directly written without
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* overhead
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@classes:
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eoUniformInit uniform initialization for doubles, floats, ints, ...
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eoBooleanInit biased init for booleans
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eoNormalInit normal intialization for doubles and floats
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eoNegExpInit negative exponential distributions "
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*/
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#ifndef eoUniformInit_h
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#define eoUniformInit_h
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#include "eoRNG.h"
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#include "eoInit.h"
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#include "eoRealBounds.h"
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#include <stdexcept>
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using eo::rng;
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/**
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The class eoUniformInit can be used in the STL apply function
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to easily randomize floats and doubles. It can also
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be used for ints and unsigneds by virtue of the static_cast
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Also present is a specialization for boolean, that will
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ignore the minima and maxima that are possibly set and will
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return an unbiased flip of a coin. For a biased flip, use the eoBoolean
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either in [0, _max) if only 1 value (_max) is given
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(or none, as _max defaults to 1.0)
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or in [_min,_max) if 2 values are given (_min, _max)
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*/
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template <class T = double> class eoUniformInit : public eoInit<T>
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{
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public :
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/** Ctor with only a max bound */
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eoUniformInit(T _max = T(1.0), eoRng& _rng = rng) :
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minim(T(0.0)), range(_max), uniform(_rng)
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{}
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/** Ctor with an eoRealBound */
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eoUniformInit(eoRealBounds & _bound, eoRng& _rng = rng) :
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minim(_bound.minimum()), range(_bound.range()), uniform(_rng)
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{}
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/** Ctor with explicit min and max */
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eoUniformInit(T _min, T _max, eoRng& _rng = rng) :
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minim(_min), range(_max-_min), uniform(_rng)
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{
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if (_min>_max)
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throw logic_error("Min is greater than Max in uniform_generator");
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}
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/**
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Generates the number, uses a static_cast to get the right behaviour
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for ints and unsigneds
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*/
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void operator()(T & _t)
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{
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_t = minim+static_cast<T>(uniform.uniform(range));
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}
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private :
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T minim;
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T range;
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eoRng& uniform;
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};
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/** Specialization for bool, does an unbiased coin flip */
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template <>
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void eoUniformInit<bool>::operator()(bool & _b)
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{
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_b = uniform.flip(0.5);
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}
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/**
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The class eoBooleanInit can be used in the STL apply function
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to easily generate random booleans with a specified bias
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*/
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class eoBooleanInit : public eoInit<bool>
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{
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public :
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eoBooleanInit(float _bias = 0.5, eoRng& _rng = rng) : bias(_bias), gen(_rng) {}
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void operator()(bool & _b) { _b = gen.flip(bias); }
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private :
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float bias;
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eoRng& gen;
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};
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/**
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The class normal_generator can be used in the STL generate function
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to easily generate gaussian distributed floats and doubles. The user
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can supply a standard deviation which defaults to 1.
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*/
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template <class T = double> class eoNormalInit : public eoInit<T>
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{
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public :
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eoNormalInit(T _stdev = T(1.0), eoRng& _rng = rng) : stdev(_stdev), normal(_rng) {}
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void operator()(T & _t) { _t = (T) normal.normal(stdev); }
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private :
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T stdev;
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eoRng& normal;
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};
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/**
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The class negexp_generator can be used in the STL generate function
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to easily generate negative exponential distributed floats and doubles. The user
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can supply a mean.
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*/
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template <class T = double> class eoNegExpInit : public eoInit<T>
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{
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public :
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eoNegExpInit(T _mean = 1.0, eoRng& _rng = rng) : mean(_mean), negexp(_rng) {}
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void operator()(T & _t) { _t = (T) negexp.negexp(mean); }
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private :
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T mean;
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eoRng& negexp;
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};
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#endif
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