jocabi.cpp

数值分析实验作业,实现雅可比的C++程序

#include <iostream>
#include <math.h>
using namespace std; 

float max(float f,float g,float h)
{float t1;
 if (f<=g)  t1=g;
	 else t1=f;
 if (t1<=h) t1=h;
 return (t1);
}

void main()
{float a[3][3]={8,-3,2,4,11,-1,6,3,12},b[3]={20,33,36};
 float x[3]={0,0,0},d[3]={0,0,0},y[3],e,sum,c=1;
 int i,j,l;
 printf("Now input e\n");
 scanf("%f",&e);
 l=0;
 while(c>=e)
 {l+=1;
	 for(i=0;i<3;i++)
     {sum=0;
      for(j=0;j<3;j++)
	  {if (j!=i) sum+=a[i][j]*x[j];
	  }
      y[i]=(b[i]-sum)/a[i][i];
     }
	 for (i=0;i<3;i++) d[i]=fabs(x[i]-y[i]);
     c=max(d[0],d[1],d[2]);
     for(i=0;i<3;i++)
      x[i]=y[i];
	 printf("%d\t",l);
 for(i=0;i<3;i++)
 printf("%f\t",y[i]);
 printf("\n");
  }

}