More cleaning-up, documentation and no unwanted changes.

src/cell.c

@@ -984,6 +984,12 @@ void cell_set_super(struct cell *c, struct cell *super) {
       if (c->progeny[k] != NULL) cell_set_super(c->progeny[k], super);
 }
 
+/**
+ * @brief Recursively drifts all particles and g-particles in a cell hierarchy.
+ *
+ * @param c The #cell.
+ * @param e The #engine (to get ti_current).
+ */
 void cell_drift(struct cell *c, const struct engine *e) {
 
   const double timeBase = e->timeBase;

src/engine.c

@@ -2616,9 +2616,8 @@ void engine_step(struct engine *e) {
   if (e->nodeID == 0) {
 
     /* Print some information to the screen */
-    printf("  %6d %14e %d %14e %10zu %10zu %21.3f\n", e->step, e->time,
-           e->ti_current, e->timeStep, e->updates, e->g_updates,
-           e->wallclock_time);
+    printf("  %6d %14e %14e %10zu %10zu %21.3f\n", e->step, e->time,
+           e->timeStep, e->updates, e->g_updates, e->wallclock_time);
     fflush(stdout);
 
     fprintf(e->file_timesteps, "  %6d %14e %14e %10zu %10zu %21.3f\n", e->step,

src/hydro/Gadget2/hydro.h

@@ -212,7 +212,6 @@ __attribute__((always_inline)) INLINE static float hydro_compute_timestep(
 __attribute__((always_inline)) INLINE static void hydro_first_init_part(
     struct part *restrict p, struct xpart *restrict xp) {
 
-  // p->ti_old = 0;
   p->ti_begin = 0;
   p->ti_end = 0;
   xp->v_full[0] = p->v[0];

src/hydro/Gadget2/hydro_part.h

@@ -50,12 +50,6 @@ struct xpart {
 /* Data of a single particle. */
 struct part {
 
-  /* Particle ID. */
-  long long id;
-
-  /* Pointer to corresponding gravity part. */
-  struct gpart* gpart;
-
   /* Particle position. */
   double x[3];
 
@@ -77,8 +71,6 @@ struct part {
   /* Particle time of end of time-step. */
   int ti_end;
 
-  // int ti_old;
-
   /* Particle density. */
   float rho;
 
@@ -132,6 +124,12 @@ struct part {
     } force;
   };
 
+  /* Particle ID. */
+  long long id;
+
+  /* Pointer to corresponding gravity part. */
+  struct gpart* gpart;
+
 } SWIFT_STRUCT_ALIGN;
 
 #endif /* SWIFT_GADGET2_HYDRO_PART_H */

src/runner.c

@@ -744,15 +744,12 @@ void runner_do_ghost(struct runner *r, struct cell *c, int timer) {
 }
 
 /**
- * @brief Drift particles and g-particles in a cell forward in time,
- *              unskipping any tasks associated with active cells.
+ * @brief Unskip any tasks associated with active cells.
  *
  * @param c The cell.
  * @param e The engine.
- * @param drift whether to actually drift the particles, will not be
- *              necessary for non-local cells.
  */
-static void runner_do_unskip(struct cell *c, struct engine *e, int drift) {
+static void runner_do_unskip(struct cell *c, struct engine *e) {
 
   /* Unskip any active tasks. */
   if (cell_is_active(c, e)) {
@@ -765,14 +762,14 @@ static void runner_do_unskip(struct cell *c, struct engine *e, int drift) {
     for (int k = 0; k < 8; k++) {
       if (c->progeny[k] != NULL) {
         struct cell *cp = c->progeny[k];
-        runner_do_unskip(cp, e, 0);
+        runner_do_unskip(cp, e);
       }
     }
   }
 }
 
 /**
- * @brief Mapper function to drift particles and g-particles forward in time.
+ * @brief Mapper function to unskip active tasks.
  *
  * @param map_data An array of #cell%s.
  * @param num_elements Chunk size.
@@ -787,18 +784,35 @@ void runner_do_unskip_mapper(void *map_data, int num_elements,
   for (int ind = 0; ind < num_elements; ind++) {
     struct cell *c = &cells[ind];
 #ifdef WITH_MPI
-    if (c != NULL) runner_do_unskip(c, e, (c->nodeID == e->nodeID));
+    if (c != NULL) runner_do_unskip(c, e);
 #else
-    if (c != NULL) runner_do_unskip(c, e, 0);
+    if (c != NULL) runner_do_unskip(c, e);
 #endif
   }
 }
-
+/**
+ * @brief Drift particles in real space.
+ *
+ * @param r The runner thread.
+ * @param c The cell.
+ * @param timer Are we timing this ?
+ */
 void runner_do_drift(struct runner *r, struct cell *c, int timer) {
 
+  TIMER_TIC;
+
   cell_drift(c, r->e);
+
+  if (timer) TIMER_TOC(timer_drift);
 }
 
+/**
+ * @brief Mapper function to drift ALL particle and g-particles forward in time.
+ *
+ * @param map_data An array of #cell%s.
+ * @param num_elements Chunk size.
+ * @param extra_data Pointer to an #engine.
+ */
 void runner_do_drift_mapper(void *map_data, int num_elements,
                             void *extra_data) {
 
@@ -812,8 +826,7 @@ void runner_do_drift_mapper(void *map_data, int num_elements,
 }
 
 /**
- * @brief Kick particles in momentum space and collect statistics (floating
- * time-step case)
+ * @brief Kick particles in momentum space and collect statistics.
  *
  * @param r The runner thread.
  * @param c The cell.
@@ -1043,8 +1056,7 @@ void *runner_main(void *data) {
 /* Check that we haven't scheduled an inactive task */
 #ifdef SWIFT_DEBUG_CHECKS
       if (cj == NULL) { /* self */
-        if (!cell_is_active(ci, e) && t->type != task_type_sort &&
-            t->type != task_type_drift)
+        if (!cell_is_active(ci, e) && t->type != task_type_sort)
           error(
               "Task (type='%s/%s') should have been skipped ti_current=%d "
               "c->ti_end_min=%d",
@@ -1060,11 +1072,6 @@ void *runner_main(void *data) {
               taskID_names[t->type], subtaskID_names[t->subtype], e->ti_current,
               ci->ti_end_min, t->flags);
 
-        /* Special treatement for drifts */
-        if (!cell_is_active(ci, e) && t->type == task_type_drift) {
-          ;
-        }
-
       } else { /* pair */
         if (!cell_is_active(ci, e) && !cell_is_active(cj, e))
           error(

src/scheduler.c

@@ -584,7 +584,6 @@ static void scheduler_splittask(struct task *t, struct scheduler *s) {
         }
 
         /* Otherwise, break it up if it is too large? */
-
       } else if (scheduler_doforcesplit && ci->split && cj->split &&
                  (ci->count > space_maxsize / cj->count)) {
 
@@ -605,8 +604,7 @@ static void scheduler_splittask(struct task *t, struct scheduler *s) {
                 tl->flags = space_getsid(s->space, &t->ci, &t->cj, shift);
               }
 
-        /* Otherwise, if not spilt, stitch-up the sorting and drift. */
-
+        /* Otherwise, if not spilt, stitch-up the sorting. */
       } else {
 
         /* Create the sort for ci. */
@@ -617,7 +615,6 @@ static void scheduler_splittask(struct task *t, struct scheduler *s) {
         else
           ci->sorts->flags |= (1 << sid);
         lock_unlock_blind(&ci->lock);
-
         scheduler_addunlock(s, ci->sorts, t);
 
         /* Create the sort for cj. */
@@ -628,7 +625,6 @@ static void scheduler_splittask(struct task *t, struct scheduler *s) {
         else
           cj->sorts->flags |= (1 << sid);
         lock_unlock_blind(&cj->lock);
-
         scheduler_addunlock(s, cj->sorts, t);
       }
 
@@ -1073,7 +1069,7 @@ void scheduler_start(struct scheduler *s) {
       if (cj == NULL) { /* self */
 
         if (ci->ti_end_min == ti_current && t->skip &&
-            t->type != task_type_sort && t->type != task_type_drift)
+            t->type != task_type_sort && t->type)
           error(
               "Task (type='%s/%s') should not have been skipped ti_current=%d "
               "c->ti_end_min=%d",
@@ -1089,12 +1085,6 @@ void scheduler_start(struct scheduler *s) {
               taskID_names[t->type], subtaskID_names[t->subtype], ti_current,
               ci->ti_end_min, t->flags);
 
-        /* Special treatement for drifts */
-        if (ci->ti_end_min == ti_current && t->skip &&
-            t->type == task_type_drift) {
-          ;
-        }
-
       } else { /* pair */
 
         if ((ci->ti_end_min == ti_current || cj->ti_end_min == ti_current) &&