78 lines
2.0 KiB
C++
78 lines
2.0 KiB
C++
// This may look like C code, but it is really -*- C++ -*-
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/*
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Copyright (C) 1988 Free Software Foundation
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written by Dirk Grunwald (grunwald@cs.uiuc.edu)
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This file is part of GNU CC.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY. No author or distributor
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accepts responsibility to anyone for the consequences of using it
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or for whether it serves any particular purpose or works at all,
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unless he says so in writing. Refer to the GNU CC General Public
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License for full details.
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Everyone is granted permission to copy, modify and redistribute
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GNU CC, but only under the conditions described in the
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GNU CC General Public License. A copy of this license is
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supposed to have been given to you along with GNU CC so you
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can know your rights and responsibilities. It should be in a
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file named COPYING. Among other things, the copyright notice
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and this notice must be preserved on all copies.
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*/
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#ifndef _Erlang_h
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#ifdef __GNUG__
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#pragma once
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#pragma interface
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#endif
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#define _Erlang_h 1
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#include <Random.h>
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class Erlang: public Random {
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protected:
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double pMean;
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double pVariance;
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int k;
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double a;
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void setState();
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public:
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Erlang(double mean, double variance, RNG *gen);
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double mean();
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double mean(double x);
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double variance();
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double variance(double x);
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virtual double operator()();
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};
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#if defined(__OPTIMIZE__) || defined(USE_LIBGXX_INLINES)
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inline void Erlang::setState() {
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k = int( (pMean * pMean ) / pVariance + 0.5 );
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k = (k > 0) ? k : 1;
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a = k / pMean;
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}
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inline Erlang::Erlang(double mean, double variance, RNG *gen) : (gen)
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{
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pMean = mean; pVariance = variance;
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setState();
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}
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inline double Erlang::mean() { return pMean; }
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inline double Erlang::mean(double x) {
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double tmp = pMean; pMean = x; setState(); return tmp;
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};
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inline double Erlang::variance() { return pVariance; }
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inline double Erlang::variance(double x) {
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double tmp = pVariance; pVariance = x; setState(); return tmp;
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}
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#endif
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#endif
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