fig.13.cpp

用于交通流研究的Wolfram模型的程序

// Fig.13.cpp 
#include "stdafx.h"
#include<iostream.h>
#include <stdlib.h>
#include <time.h>
int a[200],b[8], i,temp[200];
int match(int l,int m,int n);
float p;
int _tmain(int argc, _TCHAR* argv[])
{
	int j,n,time_steps,s[200],r;
	double C,e,f,g;	
	cout<<"Please enter the number of sites n:          "<<endl;
	cin>>n;
	cout<<"Please enter time_steps:          "<<endl;
	cin>>time_steps;
	int R,k=7;
	cout<<"Please enter the rule R:          "<<endl;
	cin>>R;
	cout<<"Please enter the probability p:          "<<endl;
	cin>>p;
	while(R>0)
	{
		b[k]=R%2;
		R=R/2;		
		k--;
	}
	//	将十进制R转化为二进制；
	srand( (unsigned)time( NULL ) );
	/* Seed the random-number generator with current time so that
	* the numbers will be different every time we run.
	*/
	for(i=0;i<n;i++)
	{ 
		if(rand()<((RAND_MAX+1)*p-1))
			a[i]=1;
		else
			a[i]=0;
	}
	//初始状态随机分布;

	for(j=1;j<=time_steps;j++)
	{
		for(i=0;i<n;i++)
			temp[i]=a[i];		
		for(i=0;i<n;i++)
		{			
			if(i==0)
				match(temp[n-1],temp[i],temp[i+1]);
			else 
			{
				if(i==(n-1))
					match(temp[i-1],temp[i],temp[0]);
				//周期性边界条件；
				else
					match(temp[i-1],temp[i],temp[i+1]);
			}
		}
	}

	//每个格点同步地按局域规则进行演化；


	for(i=0;i<n;i++)
	{
		if(a[i]==1)
			s[i]=1;
		else
			s[i]=-1;
	} 
	for(r=0;r<=40;r++)
	{
		cout<<"r="<<r<<"   ";		
		e=0;
		f=0;
		g=0;
		for(i=0;i<n;i++)
		{
			e=e+s[i];
			if(i>=0&&i<(n-r))
			{
				f=f+s[i+r];
				g=g+s[i]*s[i+r];
			}
			if(i>=(n-r)&&i<n)
			{
				f=f+s[i+r-n];
				g=g+s[i]*s[i+r-n];
			}
		}
		C=g/n-e/n*f/n;
		cout<<"C="<<C<<endl;			
	}   
	return 0;
}

int match(int l,int m,int n)
{
	if(l==1&&m==1&&n)
		a[i]=b[0];
	if(l==1&&m==1&&n==0)
		a[i]=b[1];
	if(l==1&&m==0&&n==1)
		a[i]=b[2];
	if(l==1&&m==0&&n==0)
		a[i]=b[3];
	if(l==0&&m==1&&n==1)
		a[i]=b[4];
	if(l==0&&m==1&&n==0)
		a[i]=b[5];
	if(l==0&&m==0&&n==1)
		a[i]=b[6];
	if(l==0&&m==0&&n==0)
		a[i]=b[7];
	return a[i];
}