iterative.c

这是一个迭代法实现的C代码。本算法采用的是SOR迭代法。

#include <iostream> 
#include <cmath> 
#include <cstdlib> 
#include <iomanip>
using namespace std; 

//SOR迭代法解线性方程组 
double* SOR_FA(double** a,double* x,double* b,int n)
{const int max=1000;
 int i,j,k;
 double w,c;
 double* y;
 y= new double[n];
 //跌代过程
 for(w=0.1;w<2;w+=0.1)
 {	 for(k=0;k<max;k++)
 {   for(i=0;i<n;i++)
	     y[i]=x[i];
  	 for(i=0;i<n;i++)
	 {   for(j=0,c=0;j<n;j++)
			 if(j!=i) 
				c+=a[i][j]*x[j];
			 x[i]=(b[i]-c)/a[i][i];
	 }
     for(i=0,c=0;i<n;i++)
	     c+=fabs(x[i]-y[i]);
	 if(c<0.000001)
	 {  delete []y;
	    return x;
	 }
	 for(i=0;i<n;i++)
		 x[i]=w*x[i]+(1-w)*y[i];
 }
 }
 delete []y;
 cout<<"this method isn't good\n";
 exit(1);
}

void main() 
{int i,k,n; 
 double c; 
 double** a;
 double* x;
 double* b;

 cout<<"enter the value of n\n";
 cin>>n;
 a=new double*[n];
 x=new double[n];
 b=new double[n];
 for(i=0;i<n;i++)
	 a[i]=new double[n];
  for(i=0;i<n;i++) 
     for(k=0;k<n;k++) 
         cin>>a[i][k]; 
 for(i=0;i<n;i++) 
     cin>>b[i]; 
 
 //赋初值
 for(i=0;i<n;i++) 
     cin>>x[i]; 
 
 x=SOR_FA(a,x,b,n);
 for(i=0;i<n;i++) 
            cout<<setw(15)<<setprecision(10)<<x[i]; 
}