iframe-proxy | Sunbelt Computer Software

33 lines (26 loc) · 825 Bytes

#include "NormalDistribution.h"

#include <stdexcept>

#include <cmath>

using namespace std;

NormalDistribution::NormalDistribution( double expectedValue,

double dispersion, const Random & random )

: uniform( random ),

expectedValue( expectedValue ), standardDeviation( 0.0 )

{

if( standardDeviation <= 0 )

{

throw invalid_argument( "dispersion must be a positive number" );

}

standardDeviation = sqrt( dispersion );

}

NormalDistribution::~NormalDistribution()

{}

double NormalDistribution::nextValue()

{

double r1, r2, stdNormal, result;

r1 = uniform.nextValue();

r2 = uniform.nextValue();

stdNormal = log( -2 * r1 ) * cos( 2 * M_PI * r2 );

result = expectedValue + standardDeviation * stdNormal;

return result;

}

Sunbelt Computer Software