time0 = MPI_Wtime();
    for(it = 0; it < ITMAX; it++){
        eps_ = relax(rank, N, a, b, c, w, A, MAXEPS);
        if (it % 1 == 0) {
            MPI_Allreduce(&eps_, &eps, 1, MPI_DOUBLE, MPI_MAX, MPI_COMM_WORLD); //sobiraem max eps, resultat u vseh
            if (rank==0){
                        printf("eps=%f\n", eps);
            }
        }

        if(eps < MAXEPS) {
            break;
        }
        w = 1.0 / (1.0 - 0.25 * ro * ro * w);
    }
    time2 = MPI_Wtime() - time0;
    MPI_Reduce(&time2, &time1, 1, MPI_DOUBLE, MPI_MAX, 0, MPI_COMM_WORLD); //schitaem obshchee vremya, resultat v 0-om processe
    if(rank == 0) {
        printf("Time=%f\n", time1);
        printf("Iterations=%d\n", it);
    }