gaussian_row.c

We can see that using Gauss-Seidel iterative methods need only 13 timed to make &#61541 &#61500 &#61

#include "math.h"
#include "stdio.h"
#define N 10
main()
{   double a[N][N]={0};
    double x[N],b[N],y[N],sum,max,m,n;
    int    i=0,j=0,k=0,h=0,c=0;
    int    z[N];
    sum=0;max=0;
    for(i=0;i<N;i++)
      {
        a[i][i]=3;
        a[i][i+1]=1;
        a[i+1][i]=9;
      }
      b[0]=4;
    for(i=1;i<N-1;i++)
      {
       b[i]=13;
      }
       b[N-1]=12;
    for(i=0;i<N;i++)
    {for(k=0;k<N;k++)
     if(fabs(a[k][k])>max)
     {max=fabs(a[k][k]);z[i]=k;
      for(h=0;h<N;h++)
      {m=a[i][h];n=b[i];
       a[i][h]=a[k][h];a[k][h]=m;
       b[i]=b[k];b[k]=n;
      }
     }
     else z[i]=i;
     for(j=i;j<N;j++)
     a[i][j]=a[i][j]/a[i][i];
     b[i]=b[i]/a[i][i];
     for(k=i+1;k<N;k++)
     {for(j=i;j<N;j++)
      a[k][j]=a[k][j]-a[i][j]*a[k][i];
      b[k]=b[k]-b[i]*a[k][i];
     }
    }
    for(i=N-1;i>=0;i--)
    {for(k=N-1;k>i;k--)
     sum=sum+a[i][k]*x[k];
     x[i]=(b[i]-sum)/a[i][i];
     sum=0;
    }
     for(i=0;i<N;i++)
    {c=z[i];
     y[c]=x[i];
    }
     printf("\nA\n");
    for(i=0;i<N;i++)
    {for(j=0;j<N;j++)
     printf("%4f ",a[i][j]);
     printf("\n");
    }
      getchar();
    printf("\nX\n");
    for(i=0;i<N;i++)
    {
     printf("%4f\n",y[i]);
    }
      getchar();
}