li_lu.cpp

数值分析 解线性方程组算法

// LI_LU.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"

//int _tmain(int argc, _TCHAR* argv[])
//{
//	return 0;
//}
using namespace std;

#include "math.h"
#include <conio.h>       
#include "math.h"
#include "stdio.h"
#define MaxSize 30
#define PI 3.141592654
float T_Xing (float T,float h,float is_over,float first)
{
    float start=0,result=0;
    start=first+0.5*h;
    while(start<is_over)
    {
        result=result+1.0/( start* start-1);
		start =start+h;
    }
    return(T/2.0+0.5*h*result);
}
float Romberg(int m,float h,float Tm,float tm)
{
    float TEMP=(float)(pow(4.0,(double)m)*tm/(pow(4.0,(double)m)-1));
    TEMP=TEMP-(float)(Tm/(pow(4.0,(double)m)-1));
    return (TEMP);
}
void outRomberg(float init_data,float first,float is_over,float h)
{
    float a[MaxSize][MaxSize];
	float ob=0.0;
    int i=0,j=0,is_eof=1;
    while(is_eof==1)
    {
	if((i==0) && (j==0))
        {
            a[i][j]=init_data;
            printf("%f",a[i][j]);
            printf("\n");
	 i=i+1;
        }
        else if((i!=0)&&(j==0))
        {
            a[i][j]=T_Xing(a[i-1][0],h,is_over,first);
            printf("%f",a[i][j]);
            printf(" ");

            for(j=1;j<=i;)
            {
                a[i][j]=Romberg(i,h,a[i-1][j-1],a[i][j-1]);
                printf("%f",a[i][j]);
                printf(" ");
	     j++;
            }
	     printf("\n");
             j=0;
	    ob=fabs(a[i][j]-a[i-1][i-1]);

            if(fabs(a[i][j]-a[i-1][i-1])<0.000001)
               is_eof=0;
            h=h*0.5;
	    i=i+1;
        }        
    }
}

main()
{ 
 float first,is_over,h=0,init_data=0;
 first=2;
 is_over=3;
init_data=(1.0/(first*first-1)+1.0/(is_over*is_over-1))/2.0;
    h=(is_over-first);
    outRomberg(init_data,first,is_over,h);
 getch();    
}