Gauss Jacobi Inversion Method

Algorithm Of Gauss Jacobi Inversion Method

GaussJacobiinversion(a,n)
{
                                               
for(k=0 to k<n)
{

	for(c=n*2 to c>=0)
	{
	a[k][c]=a[k][c]/a[k][k]
	}
		for(r=0 to r<n)
		{
		if(k!=r)
		{
		m=a[r][k]
		for(col=0col<n*2col++)
		a[r][col]=a[r][col]-m*a[k][col]
		}
		}
	}
}                                               



C Program For Gauss Jacobi Inversion Method

Source Code:

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>

linkfloat()
{
 float a,*b;
 b=&a;
 a=*b;
}

void show(float **A,int n1,int n2)
{
   int i,j;
   for(i=1;i<=n1;i++)
   {
      for(j=1;j<=n2;j++)
      {
  printf("\t%g",A[i][j]);
      }
      printf("\n");
   }
}

void gauss_jacob_inv(float **A,float B[5][5],int n)
{
   int k,i,j,row,col,n1;
   float m,s,R[5],C[5][5];
   n1=n;
   for(k=1;k<=n;k++)
   {
      for(col=2*n;col>=1;col--)
      {
  A[k][col]=A[k][col]/A[k][k];
      }
  for(row=1;row<=n;row++)
  {
     if(k!=row)
     {
       m=A[row][k];
       for(col=1;col<=2*n;col++)
       {
  A[row][col]=A[row][col]-m*A[k][col];
       }
     }
  }
      printf("\nStep %d:",k);
      show(A,n1,2*n1);
      printf("--------------------------------------");
   }
   printf("\nLast step:\n");
   show(A,n1,2*n1);
   for(i=1;i<=n;i++)
   {
      j=1;
      k=n+1;
      while(j<=n && k<=2*n)
      {
  C[i][j]=A[i][k];
  j++;
  k++;
      }
   }
   printf("\nmatrix c :\n");
   for(i=1;i<=n;i++)
   {
      for(j=1;j<=n;j++)
      {
 printf("  %g",C[i][j]);
      }
      printf("\n");
   }
   for(i=1;i<=n;i++)
   {
      s=0;
      for(j=1;j<=n;j++)
      {
  s=s+C[i][j]*B[j][1];
      }
      R[i]=s;
   }
   for(i=1;i<=n;i++)
   {
      printf("\nX%d=%g",i,R[i]);
   }
}


void main()
{
   int n,r,c,j,i;
   float **A,B[5][5];
   clrscr();
   printf("\nEnter number of variables:");
   scanf("%d",&n);
   r=n+1;
   c=n+2;
   A=(float **)malloc(sizeof(float *)*r);
   for(i=1;i<=r;i++)
   {
      A[i]=(float *)malloc(sizeof(float)*2*c);
   }
   for(i=1;i<=n;i++)
   {
      for(j=1;j<=n;j++)
      {
   printf("\nEnter term %d of equation %d:",j,i);
   fflush(stdin);
   scanf("%f",&A[i][j]);
      }
   }
   for(i=1;i<=n;i++)
   {
     for(j=1;j<=1;j++)
     {
      printf("\nEnter const part of eqn%d :",i);
      fflush(stdin);
      scanf("%f",&B[i][j]);
     }
   }
   for(i=1;i<=n;i++)
   {
      for(j=1;j<=2*n;j++)
      {
  if(j>n)
  {
     if(j==i+3)
     {
        A[i][j]=1;
     }
     else
     {
        A[i][j]=0;
     }
  }
      }
   }
   printf("\nInitially: matrix A\n");
   show(A,n,2*n);
   printf("\n\t\tmatrix B\n");
   for(i=1;i<=n;i++)
   {
      for(j=1;j<=1;j++)
      {
 printf("%g",B[i][j]);
      }
      printf("\n");
   }
   gauss_jacob_inv(A,B,n);
   getch();
}