randomgen250.cpp

计算IsingModel的磁化强度

#include "RandomGen250.h"

#define AMOL .23283064365386962890625e-9
#define NBIT 32

CRandomGen250::CRandomGen250(void)
{
	for( int i = 0; i < 256; i++ )
		m_ir[i] = i;
	m_k = 0;
	m_iran_ks = 0;
}

CRandomGen250::~CRandomGen250(void)
{
}

double CRandomGen250::GetRandom(void)
{
	m_k = ( m_k + 1 ) & 255;

	m_ir[ m_k ] = m_ir[ ( ( m_k - 250 ) & 255 ) ] ^ m_ir[ ( ( m_k - 103 ) & 255 ) ];

	m_iran_ks = m_ir[ m_k ];

	return ( m_iran_ks * AMOL + 0.5 );

}

void CRandomGen250::SetRandomSeed( int iSeed )
{
	int ibm, idum, i;


	ibm = 2 * iSeed + 1;

	for( m_k = 0; m_k < 256; m_k++ )

	{

		idum = 0;

		for( i = 1; i <= NBIT; i++ )

		{

			idum = idum * 2;

			ibm = ibm * 16807;

			if( ibm < 0 )
				idum++;
		
		}

		m_ir[ m_k ] = idum;

	}


	m_k = 0;


	for( i = 0; i < 100000; i++ )

		this->GetRandom();
}