Also update the counter of gravity self/pair tasks when linking them.

src/cell.c

@@ -763,6 +763,9 @@ void cell_clean_links(struct cell *c, void *data) {
 
   c->force = NULL;
   c->nr_force = 0;
+
+  c->grav = NULL;
+  c->nr_grav = 0;
 }
 
 /**

src/engine.c

@@ -1409,6 +1409,7 @@ static inline void engine_make_gravity_dependencies(struct engine *e,
 
   /* link to cell. */
   engine_addlink(e, &c->grav, gravity);
+  atomic_inc(&c->nr_grav);
 }
 
 /**
@@ -1420,11 +1421,9 @@ static inline void engine_make_gravity_dependencies(struct engine *e,
  * @param gravity The gravity task to link.
  * @param c The cell.
  */
-static inline void engine_make_external_gravity_dependencies(struct engine *e,
-                                                             struct scheduler
-                                                             *sched, struct
-                                                             task *gravity,
-                                                             struct cell *c) {
+static inline void engine_make_external_gravity_dependencies(
+    struct engine *e, struct scheduler *sched, struct task *gravity,
+    struct cell *c) {
 
   /* init --> external gravity --> kick */
   scheduler_addunlock(sched, c->super->init, gravity);
@@ -1432,6 +1431,7 @@ static inline void engine_make_external_gravity_dependencies(struct engine *e,
 
   /* link to cell. */
   engine_addlink(e, &c->grav, gravity);
+  atomic_inc(&c->nr_grav);
 }
 
 /**

src/space.c

@@ -395,6 +395,7 @@ void space_regrid(struct space *s, double cell_max, int verbose) {
       s->cells_top[k].nr_density = 0;
       s->cells_top[k].nr_gradient = 0;
       s->cells_top[k].nr_force = 0;
+      s->cells_top[k].nr_grav = 0;
       s->cells_top[k].density = NULL;
       s->cells_top[k].gradient = NULL;
       s->cells_top[k].force = NULL;
@@ -587,8 +588,7 @@ void space_rebuild(struct space *s, double cell_max, int verbose) {
   for (size_t k = 1; k < nr_parts; k++) {
     if (ind[k - 1] > ind[k]) {
       error("Sort failed!");
-    } else if (ind[k] != cell_getid(s->cdim, 
-                                    s->parts[k].x[0] * s->iwidth[0],
+    } else if (ind[k] != cell_getid(s->cdim, s->parts[k].x[0] * s->iwidth[0],
                                     s->parts[k].x[1] * s->iwidth[1],
                                     s->parts[k].x[2] * s->iwidth[2])) {
       error("Incorrect indices!");