JAcobi

//Jacobi

#include <stdio.h>
#include <iostream.h>
#include <conio.h>
#include <math.h>

#define N 7

typedef unsigned char LOGIC;

LOGIC Jacobi(int,float A[][N],float *,float *,float);

int main(void)
{
  int i,j;
  float er=0.001;
  float A[N][N],B[N],X[N];
  int grad;

  printf("\nIntroduceti gradul : ");
  scanf("%d",&grad);
  for(i=1;i<=grad;i++)
    for(j=1;j<=grad;j++)
    {
      printf("\nA[%d][%d] = ",i,j);
      scanf("%f",&A[i][j]);
      }
  for(i=1;i<=grad;i++)
    {
        printf("\nB[%d] = ",i);
        scanf("%f",&B[i]);
        X[i] = B[i];    // stabilirea valorilor vectorului de start, egal cu
                        // vectorul termenilor liberi
        }

// apelul functiei si verificarea rezultatelor
  if(Jacobi(grad,A,B,X,er))
    {
    for(i=1;i<=grad;i++)   printf("\nX[%d] = %f",i,X[i]);
    }
  else printf("\nEroare");

  getch();
  return 1;
}

LOGIC Jacobi(int n,float A[][N],float *B,float *X,float er)
{
  int i,j;
  float sum;
  float Xn[N],Xn_1[N];
  LOGIC sem;
  for(i=1;i<=n;i++) {
  sum=0;
  for(j=1;j<=n;j++) sum=sum+fabs(A[i][j]);
  if(sum>2*fabs(A[i][i])) {return(0);}
  }

  for(i=1;i<=n;i++) Xn[i]=X[i];
  do {
  sem=1;
  for(i=1;i<=n;i++) Xn_1[i]=Xn[i];
  for(i=1;i<=n;i++)
  {
  Xn[i]=B[i];
  for(j=1;j<=n;j++) if(j!=i) Xn[i]=Xn[i]-A[i][j]*Xn_1[j];
  Xn[i]=Xn[i]/A[i][i];
  cout << " componenta " << i << " este " << Xn[i];
  }
  cout << "\n";

  for(i=1;i<=n;i++) if(fabs(Xn[i]-Xn_1[i])>er) sem=0;
  } while(sem==0);

  for(i=1;i<=n;i++) X[i]=Xn[i];
  return(1);
}