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eodev/eo/src/utils/rnd_generators.h

125 lines
3.6 KiB
C++

/* -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
-----------------------------------------------------------------------------
rnd_generators.h
Some utility functors for generating random generators:
uniform_generator : generates uniform floats or doubles
random_generator : generates unsigneds, ints etc.
normal_generator : normally distributed floats or doubles
(c) Maarten Keijzer (mak@dhi.dk) and GeNeura Team, 1999, 2000
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Contact: todos@geneura.ugr.es, http://geneura.ugr.es
*/
//-----------------------------------------------------------------------------
#ifndef eoRND_GENERATORS_H
#define eoRND_GENERATORS_H
#include "eoRNG.h"
/**
The class uniform_generator can be used in the STL generate function
to easily generate random floats and doubles between [0, _max). _max
defaults to 1.0
*/
template <class T = double> class uniform_generator
{
public :
uniform_generator(T _max = T(1.0), eoRng& _rng = rng) : maxim(_max), uniform(_rng) {}
T operator()(void) { return (T) uniform.uniform(maxim); }
private :
T maxim;
eoRng& uniform;
};
/**
The class boolean_generator can be used in the STL generate function
to easily generate random booleans with a specified bias
*/
class boolean_generator
{
public :
boolean_generator(float _bias = 0.5, eoRng& _rng = rng) : bias(_bias), gen(_rng) {}
bool operator()(void) { return gen.flip(0.5); }
private :
float bias;
eoRng& gen;
};
/**
The class random_generator can be used in the STL generate function
to easily generate random ints between [0, _max).
*/
template <class T = uint32> class random_generator
{
public :
random_generator(T _max, eoRng& _rng = rng) : maxim(_max), random(_rng) {}
T operator()(void) { return (T) random.random(max); }
private :
T maxim;
eoRng& random;
};
/// Specialization for bool
template <>
bool random_generator<bool>::operator()(void)
{
return random.flip(0.5);
}
/**
The class normal_generator can be used in the STL generate function
to easily generate gaussian distributed floats and doubles. The user
can supply a standard deviation which defaults to 1.
*/
template <class T = double> class normal_generator
{
public :
normal_generator(T _stdev = T(1.0), eoRng& _rng = rng) : stdev(_stdev), normal(_rng) {}
T operator()(void) { return (T) normal.normal(stdev); }
private :
T stdev;
eoRng& normal;
};
/**
The class negexp_generator can be used in the STL generate function
to easily generate negative exponential distributed floats and doubles. The user
can supply a mean.
*/
template <class T = double> class negexp_generator
{
public :
negexp_generator(T _mean = 1.0, eoRng& _rng = rng) : mean(_mean), negexp(_rng) {}
T operator()(void) { return (T) negexp.negexp(mean); }
private :
T mean;
eoRng& negexp;
};
#endif