diff --git a/src/fof.c b/src/fof.c
index 718b654ffc4de96d96269d06ae76f53bc77b1dd5..8a7635f424fa326eb35d174f31a522db7db26fcf 100644
--- a/src/fof.c
+++ b/src/fof.c
@@ -58,8 +58,8 @@ void fof_init(struct space *s, long long Ngas, long long Ngparts) {
}
-/* Finds the root ID of the group a particle exists in. */
-__attribute__((always_inline)) INLINE static int fof_find(const int i,
+/* Finds the global root ID of the group a particle exists in. */
+__attribute__((always_inline)) INLINE static int fof_find_global(const int i,
int *group_index) {
int root = node_offset + i;
@@ -83,9 +83,8 @@ __attribute__((always_inline)) INLINE static int fof_find(const int i,
return root;
}
-#ifdef WITH_MPI
-/* Finds the root ID of the group a particle exists in. */
-__attribute__((always_inline)) INLINE static int fof_find_global(const int i,
+/* Finds the local root ID of the group a particle exists in. */
+__attribute__((always_inline)) INLINE static int fof_find(const int i,
int *group_index) {
int root = i;
@@ -106,7 +105,6 @@ __attribute__((always_inline)) INLINE static int fof_find_global(const int i,
return root;
}
-#endif
/* Updates the root and checks that its value has not been changed since being read. */
__attribute__((always_inline)) INLINE static int update_root(
@@ -135,8 +133,8 @@ __attribute__((always_inline)) INLINE static void fof_union(int *root_i, const i
/* Loop until the root can be set to a new value. */
do {
- int root_i_new = fof_find(*root_i - node_offset, group_index);
- const int root_j_new = fof_find(root_j - node_offset, group_index);
+ int root_i_new = fof_find(*root_i, group_index);
+ const int root_j_new = fof_find(root_j, group_index);
/* Skip particles in the same group. */
if(root_i_new == root_j_new) return;
@@ -146,7 +144,7 @@ __attribute__((always_inline)) INLINE static void fof_union(int *root_i, const i
if(root_j_new < root_i_new) {
/* Updates the root and checks that its value has not been changed since being read. */
- result = update_root(&group_index[root_i_new - node_offset], root_j_new);
+ result = update_root(&group_index[root_i_new], root_j_new);
/* Update root_i on the fly. */
*root_i = root_j_new;
@@ -154,7 +152,7 @@ __attribute__((always_inline)) INLINE static void fof_union(int *root_i, const i
else {
/* Updates the root and checks that its value has not been changed since being read. */
- result = update_root(&group_index[root_j_new - node_offset], root_i_new);
+ result = update_root(&group_index[root_j_new], root_i_new);
/* Update root_i on the fly. */
*root_i = root_i_new;
@@ -372,12 +370,12 @@ void fof_search_cell(struct space *s, struct cell *c) {
const double piz = pi->x[2];
/* Find the root of pi. */
- int root_i = fof_find(offset[i] - node_offset, group_index);
+ int root_i = fof_find(offset[i], group_index);
for (size_t j = i + 1; j < count; j++) {
/* Find the root of pj. */
- const int root_j = fof_find(offset[j] - node_offset, group_index);
+ const int root_j = fof_find(offset[j], group_index);
//long long group_j = group_id[root_j];
/* Skip particles in the same group. */
@@ -446,12 +444,12 @@ void fof_search_pair_cells(struct space *s, struct cell *ci, struct cell *cj) {
const double piz = pi->x[2] - shift[2];
/* Find the root of pi. */
- int root_i = fof_find(offset_i[i] - node_offset, group_index);
+ int root_i = fof_find(offset_i[i], group_index);
for (size_t j = 0; j < count_j; j++) {
/* Find the root of pj. */
- const int root_j = fof_find(offset_j[j] - node_offset, group_index);
+ const int root_j = fof_find(offset_j[j], group_index);
/* Skip particles in the same group. */
if (root_i == root_j) continue;
@@ -529,7 +527,7 @@ void fof_search_pair_cells_foreign(struct space *s, struct cell *ci, struct cell
const double piz = pi->x[2] - shift[2];
/* Find the root of pi. */
- const int root_i = fof_find(offset_i[i] - node_offset, group_index);
+ const int root_i = fof_find_global(offset_i[i] - node_offset, group_index);
for (size_t j = 0; j < count_j; j++) {
@@ -583,7 +581,7 @@ void fof_search_pair_cells_foreign(struct space *s, struct cell *ci, struct cell
const double pjz = pj->x[2] - shift[2];
/* Find the root of pj. */
- int root_j = fof_find(offset_j[j] - node_offset, group_index);
+ int root_j = fof_find_global(offset_j[j] - node_offset, group_index);
for (size_t i = 0; i < count_i; i++) {
@@ -821,6 +819,9 @@ void fof_search_foreign_cells(struct space *s) {
size_t nr_links = 0;
int count = 0;
+ /* Make group IDs globally unique. */
+ for (size_t i = 0; i < s->nr_gparts; i++) group_index[i] += node_offset;
+
/* Loop over top-level cells and find local cells that touch foreign cells. Calculate the total number of possible links between these cells. */
for (size_t cid = 0; cid < nr_cells; cid++) {
@@ -911,7 +912,7 @@ void fof_search_foreign_cells(struct space *s) {
/* Set each particle's root found in the local FOF.*/
for(int k=0; k<local_cell->gcount; k++) {
- const int root = fof_find(offset[k] - node_offset, group_index);
+ const int root = fof_find_global(offset[k] - node_offset, group_index);
gparts[k].root = root;
}
}
@@ -1238,7 +1239,7 @@ void fof_search_tree(struct space *s) {
error("Failed to allocate list of particle group IDs for FOF search.");
/* Initial group ID is particle offset into array. */
- for (size_t i = 0; i < nr_gparts; i++) s->fof_data.group_index[i] = node_offset + i;
+ for (size_t i = 0; i < nr_gparts; i++) s->fof_data.group_index[i] = i;
for (size_t i = 0; i < nr_gparts; i++) s->fof_data.group_id[i] = gparts[i].id_or_neg_offset;
group_index = s->fof_data.group_index;
@@ -1262,7 +1263,7 @@ void fof_search_tree(struct space *s) {
/* Calculate the total number of particles in each group, group mass and the total number of groups. */
//for (size_t i = 0; i < nr_gparts; i++) {
- // int root = fof_find(i - node_offset, group_index);
+ // int root = fof_find_global(i - node_offset, group_index);
// group_size[root - node_offset]++;
//}
@@ -1446,7 +1447,7 @@ void fof_dump_group_data(char *out_file, const size_t nr_gparts, int *group_inde
fprintf(file, "#---------------------------------------\n");
for (size_t i = 0; i < nr_gparts; i++) {
- const int root = fof_find(i, group_index);
+ const int root = fof_find_global(i - node_offset, group_index);
fprintf(file, " %7zu %7d %7d %10lld\n", i, root, group_size[i], group_id[i]);
}