/* RTcmix  - Copyright (C) 2004  The RTcmix Development Team   See ``AUTHORS'' for a list of contributors. See ``LICENSE'' for   the license to this software and for a DISCLAIMER OF ALL WARRANTIES.*/ #include "RandGen.h" #define _USE_MATH_DEFINES // for Visual Studio#include <math.h>#include <assert.h> // Classes for generating random numbers   JGG, 6/22/04// Most of this code is based on C functions written by Luke Dubois.// One class is based on code written by Mara Helmuth. inline double dmax(double x, double y) { return (x > y) ? x : y; }inline double dmin(double x, double y) { return (x < y) ? x : y; }  // Base class ----------------------------------------------------------------- RandGen::~RandGen() {} // Return a random number in range [0, 1]inline double RandGen::rawvalue(){	_randx = (_randx * 1103515245) + 12345;	int k = (_randx >> 16) & 077777;	return (double) k / 32768.0;} // Scale <num>, which must be in range [0, 1], to fit range [_min, _max]inline double RandGen::fitrange(double num) const{	assert(num >= 0.0 && num <= 1.0);	return _min + (num * (_max - _min));}  // Linear distribution subclass ----------------------------------------------- LinearRandom::LinearRandom(double min, double max, int seed)	: RandGen(min, max, seed) {} LinearRandom::~LinearRandom() {} double LinearRandom::value(){	return fitrange(rawvalue());}  // Low-weighted linear distribution subclass ---------------------------------- LowLinearRandom::LowLinearRandom(double min, double max, int seed)	: RandGen(min, max, seed) {} LowLinearRandom::~LowLinearRandom() {} double LowLinearRandom::value(){	double num1 = rawvalue();	double num2 = rawvalue();	return fitrange(dmin(num1, num2));}  // High-weighted linear distribution subclass --------------------------------- HighLinearRandom::HighLinearRandom(double min, double max, int seed)	: RandGen(min, max, seed) {} HighLinearRandom::~HighLinearRandom() {} double HighLinearRandom::value(){	double num1 = rawvalue();	double num2 = rawvalue();	return fitrange(dmax(num1, num2));}  // Triangle distribution subclass --------------------------------------------- TriangleRandom::TriangleRandom(double min, double max, int seed)	: RandGen(min, max, seed) {} TriangleRandom::~TriangleRandom() {} double TriangleRandom::value(){	double num1 = rawvalue();	double num2 = rawvalue();	double tmp = 0.5 * (num1 + num2);	return fitrange(tmp);}  // Gaussian distribution subclass --------------------------------------------- GaussianRandom::GaussianRandom(double min, double max, int seed)	: RandGen(min, max, seed) {} GaussianRandom::~GaussianRandom() {} double GaussianRandom::value(){	const int N = 12;	const double halfN = 6.0;	const double scale = 1.0;	const double mu = 0.5;	const double sigma = 0.166666; 	double num;	do {		num = 0.0;		for (int j = 0; j < N; j++)			num += rawvalue();		num = sigma * scale * (num - halfN) + mu;	} while (num < 0.0 || num > 1.0); 	return fitrange(num);}  // Cauchy distribution subclass ----------------------------------------------- CauchyRandom::CauchyRandom(double min, double max, int seed)	: RandGen(min, max, seed) {} CauchyRandom::~CauchyRandom() {} double CauchyRandom::value(){	const double alpha = 0.00628338; 	double num;	do {		do {			num = rawvalue();		} while (num == 0.5);		num = (alpha * tan(num * M_PI)) + 0.5;	} while (num < 0.0 || num > 1.0); 	return fitrange(num);}  // Probability distribution subclass ------------------------------------------// Based on code by Mara Helmuth////    <min> and <max> set the range within which the random numbers fall.////    <mid> sets the mid-point of the range, which has an effect whenever//    <tight> is not 1.////    <tight> governs the degree to which the random numbers adhere either//    to the mid-point or to the extremes of the range:////       tight         effect//       -------------------------------------------------------------//       0             only the <min> and <max> values appear//       1             even distribution//       > 1           numbers cluster ever more tightly around <mid>//       100           almost all numbers are equal to <mid> ProbRandom::ProbRandom(double min, double max, double mid, double tight,	int seed)	: RandGen(min, max, mid, tight, seed) {} ProbRandom::~ProbRandom() {} double ProbRandom::value(){	const double min = getmin();	const double max = getmax();	const double mid = getmid();	const double tight = gettight();	double hirange = max - mid;	double lowrange = mid - min;	double range = dmax(hirange, lowrange); 	double num;	do {		double sign;		num = rawvalue();       // num is [0,1]		if (num > 0.5)			sign = 1.0;		else			sign = -1.0;		num = mid + (sign * (pow(rawvalue(), tight) * range));	} while (num < min || num > max); 	return num;} // RandomOscil RandomOscil::RandomOscil(RandGen *gen, double srate, double freq)	: _gen(gen), _srate(srate){	setfreq(freq);	_counter = _limit;		// trigger first _gen->value()} RandomOscil::~RandomOscil(){	delete _gen;} void RandomOscil::setfreq(double freq){	_limit = (int) (_srate / freq);} double RandomOscil::next(){	if (_counter >= _limit) {		_curval = _gen->value();		_counter = 0;	}	else		_counter++;	return _curval;}