0716 Iteration method

[markoo (上行下笑阿..)]

// class6.cpp : 定義主控台應用程式的進入點。
//

#include "stdafx.h"
#include <stdlib.h>
#include <math.h>
#include <time.h>
#define Num 3
#define Max(a,b) (a>b)?a:b
void mprint(double A[Num][Num], double B[Num]);
void vprint(double B[Num]);
double tolerance(double old_x[Num], double new_x[Num]);
time_t t1;
int main()
{
        int i,j;
        double A[Num][Num];
        double A2[Num][Num];
        double B[Num];
        double B2[Num];
        double temp;
        double ans[Num];//final answer
        double old_iterate[Num];
        double iterate[Num];
        double tol = 0.001;
        srand(time(&t1));
        for (i=0;i<Num;i++)
        {
                B[i] = rand()/32767.0;
                B2[i]= B[i];
                for (j=0;j<Num;j++)
                {
                        A[i][j] = rand()/32767.0;
                        A2[i][j] = A[i][j];
                }
        }
        printf("The matrix is now as following:\n");
        mprint(A,B);
        for (i=0;i<Num;i++)
        {
                old_iterate[i]=0;
                iterate[i] = old_iterate[i];
        }
        do
        {
                for (i=0;i<Num;i++)
                {
                        iterate[i]=0;
                        temp  = B[i];
                        for (j=0;j<Num;j++)     temp-=A[i][j]*iterate[j];
                        iterate[i] = temp/A[i][i];
                }
                printf("The previous iteration values are:\n");
                vprint(old_iterate);
                printf("The present iteration values are:\n");
                vprint(iterate);
                temp = tolerance(old_iterate,iterate);
                for (i=0;i<Num;i++) old_iterate[i] = iterate[i];
                printf("tolerance = %lf\n",temp);
                system("pause");
        }while (tol<=temp);
        for (i=0;i<Num;i++)     printf("solution x[%d] = %lf\n",i+1,iterate[i]);
        for (i=0;i<Num;i++)
        {
                temp = 0;
                for (j=0;j<Num;j++)     temp+=A2[i][j]*iterate[j];
                printf("%dth:old value = %lf, new value =%lf\n",i+1,B2[i],temp);
        }
        return 0;
}

void mprint(double A[Num][Num], double B[Num])
{
        int i,j;
        for (i=0;i<Num;i++)
        {
                for (j=0;j<Num-1;j++) printf("%lf ",A[i][j]);
                printf("%lf | ",A[i][Num-1]);
                printf("%lf\n",B[i]);
        }
}
void vprint(double B[Num])
{
        int i;
        for (i=0;i<Num;i++) printf("%lf\n",B[i]);
}
double tolerance(double old_x[Num], double new_x[Num])
{
        int i;
        double ans=0;
        double temp=0;
        for (i=0;i<Num;i++)     ans = Max(ans,fabs(old_x[i]-new_x[i]));
        return ans;
}

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