int main(int argc, char** argv)
{
int i, j, N, flag;
Matrix A=NULL, Q=NULL;
Vector b, grid, e, lambda=NULL;
double time, sum, h, tol=1e-6;
int rank, size;
int mpi_top_coords;
int mpi_top_sizes;
init_app(argc, argv, &rank, &size);
if (argc < 3) {
printf("need two parameters, N and flag [and tolerance]\n");
printf(" - N is the problem size (in each direction\n");
printf(" - flag = 1 -> Matrix-free Gauss-Jacobi iterations\n");
printf(" - flag = 2 -> Matrix-free red-black Gauss-Seidel iterations\n");
printf(" - flag = 3 -> Matrix-free CG iterations\n");
printf(" - flag = 4 -> Matrix-free additive schwarz preconditioned+Cholesky CG iterations\n");
printf(" - flag = 5 -> Matrix-free additive schwarz preconditioned+CG CG iterations\n");
return 1;
}
N=atoi(argv[1]);
flag=atoi(argv[2]);
if (argc > 3)
tol=atof(argv[3]);
if (N < 0) {
if (rank == 0)
printf("invalid problem size given\n");
close_app();
return 2;
}
if (flag < 0 || flag > 5) {
if (rank == 0)
printf("invalid flag given\n");
close_app();
return 3;
}
if (flag == 2 && (N-1)%2 != 0 && ((N-1)/size) % 2 != 0) {
if (rank == 0)
printf("need an even size (per process) for red-black iterations\n");
close_app();
return 4;
}
// setup topology
mpi_top_coords = 0;
mpi_top_sizes = 0;
MPI_Dims_create(size, 1, &mpi_top_sizes);
int periodic = 0;
MPI_Comm comm;
MPI_Cart_create(MPI_COMM_WORLD, 1, &mpi_top_sizes, &periodic, 0, &comm);
MPI_Cart_coords(comm, rank, 1, &mpi_top_coords);
b = createVectorMPI(N+1, &comm, 1, 1);
e = createVectorMPI(N+1, &comm, 1, 1);
grid = equidistantMesh(0.0, 1.0, N);
h = 1.0/N;
evalMeshDispl(b, grid, source);
scaleVector(b, pow(h, 2));
evalMeshDispl(e, grid, exact);
axpy(b, e, alpha);
b->data[0] = b->data[b->len-1] = 0.0;
if (flag == 4) {
int size = b->len;
if (b->comm_rank == 0)
size--;
if (b->comm_rank == b->comm_size-1)
size--;
A1D = createMatrix(size, size);
A1Dfactored = 0;
diag(A1D, -1, -1.0);
diag(A1D, 0, 2.0+alpha);
diag(A1D, 1, -1.0);
}
int its=-1;
char method[128];
time = WallTime();
if (flag == 1) {
its=GaussJacobiPoisson1D(b, tol, 1000000);
sprintf(method,"Gauss-Jacobi");
}
if (flag == 2) {
its=GaussSeidelPoisson1Drb(b, tol, 1000000);
sprintf(method,"Gauss-Seidel");
}
if (flag == 3) {
its=cgMatrixFree(Poisson1D, b, tol);
sprintf(method,"CG");
}
if (flag == 4 || flag == 5) {
its=pcgMatrixFree(Poisson1D, Poisson1DPre, b, tol);
sprintf(method,"PCG");
}
if (rank == 0) {
printf("%s used %i iterations\n", method, its);
printf("elapsed: %f\n", WallTime()-time);
}
evalMeshDispl(e, grid, exact);
axpy(b,e,-1.0);
b->data[0] = b->data[b->len-1] = 0.0;
h = maxNorm(b);
if (rank == 0)
printf("max error: %e\n", h);
if (A)
freeMatrix(A);
if (Q)
freeMatrix(Q);
freeVector(grid);
freeVector(b);
freeVector(e);
if (lambda)
freeVector(lambda);
if (A1D)
freeMatrix(A1D);
MPI_Comm_free(&comm);
close_app();
return 0;
}
int main(int argc, char** argv)
{
int rank, size;
init_app(argc, argv, &rank, &size);
if (argc < 2) {
printf("usage: %s <N> [L]\n",argv[0]);
close_app();
return 1;
}
/* the total number of grid points in each spatial direction is (N+1) */
/* the total number of degrees-of-freedom in each spatial direction is (N-1) */
int N = atoi(argv[1]);
int M = N-1;
double L=1.0;
if (argc > 2)
L = atof(argv[2]);
double h = L/N;
Vector grid = createVector(M);
for (int i=0;i<M;++i)
grid->data[i] = (i+1)*h;
int coords[2] = {0};
int sizes[2] = {1};
#ifdef HAVE_MPI
sizes[0] = sizes[1] = 0;
MPI_Dims_create(size,2,sizes);
int periodic[2];
periodic[0] = periodic[1] = 0;
MPI_Comm comm;
MPI_Cart_create(MPI_COMM_WORLD,2,sizes,periodic,0,&comm);
MPI_Cart_coords(comm,rank,2,coords);
#endif
int* len[2];
int* displ[2];
splitVector(M, sizes[0], &len[0], &displ[0]);
splitVector(M, sizes[1], &len[1], &displ[1]);
#ifdef HAVE_MPI
Matrix u = createMatrixMPI(len[0][coords[0]]+2, len[1][coords[1]]+2, M, M, &comm);
#else
Matrix u = createMatrix(M+2, M+2);
#endif
evalMeshDispl(u, grid, grid, poisson_source,
displ[0][coords[0]], displ[1][coords[1]]);
scaleVector(u->as_vec, h*h);
double time = WallTime();
GS(u, 1e-6, 5000);
evalMesh2Displ(u, grid, grid, exact_solution, -1.0,
displ[0][coords[0]], displ[1][coords[1]]);
double max = maxNorm(u->as_vec);
if (rank == 0) {
printf("elapsed: %f\n", WallTime()-time);
printf("max: %f\n", max);
}
freeMatrix(u);
freeVector(grid);
for (int i=0;i<2;++i) {
free(len[i]);
free(displ[i]);
}
close_app();
return 0;
}
