// Advance the global grid one step.
void gol_advance(void)
{
// Input grid.
struct grid *in = grids[cur_grid];
// Output grid
struct grid *out = grids[1 - cur_grid];
// TODO Communicate boundary elements with neighboring processes (left and/or right).
int rank = 0, num_procs = 0;
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &num_procs);
int right = ( rank + 1) % num_procs;
int left = ( rank + num_procs - 1) % num_procs;
if(num_procs > 1) {
if(rank == 0) {
mpi_get_row(in, in->width, rank, rank+1, right);
}
else if(rank+1 == num_procs) {
mpi_get_row(in, 1, rank, rank-1, left);
}
else {
mpi_get_row(in, 1, rank, rank-1, left);
mpi_get_row(in, in->width, rank, rank+1, right);
}
}
// Loop over all interior cells and advance them.
for (int col = 0; col < in->width; ++col)
{
for (int row = 0; row < in->height; ++row)
{
advance_cell(in, out, row, col);
}
}
// Swap input/output grids.
cur_grid = 1 - cur_grid;
}
/* The main function, a fairly generic backtracking algorithm. */
void solve_sudoku(void)
{
int pos = 0;
while (1) {
while (pos < 81 && known[pos/9][pos%9]) {
++pos;
}
if (pos >= 81) {
break;
}
if (advance_cell(pos/9, pos%9)) {
++pos;
} else {
do {
--pos;
} while (pos >= 0 && known[pos/9][pos%9]);
if (pos < 0) {
break;
}
}
}
}