src/runner_doiact.h

src/cell.c

@@ -981,3 +981,25 @@ void cell_set_super(struct cell *c, struct cell *super) {
     for (int k = 0; k < 8; k++)
       if (c->progeny[k] != NULL) cell_set_super(c->progeny[k], super);
 }
+
+/**
+ * Set ti_old of a #cell and all its progenies to a new value.
+ *
+ * @param c The #cell.
+ * @param ti_current The new value of ti_old.
+ */
+void cell_set_ti_old(struct cell *c, int ti_current) {
+
+  /* Set this cell */
+  c->ti_old = ti_current;
+
+  /* Recurse */
+  if (c->split) {
+    for (int k = 0; k < 8; ++k) {
+      if (c->progeny[k] != NULL) {
+        struct cell *cp = c->progeny[k];
+        cell_set_ti_old(cp, ti_current);
+      }
+    }
+  }
+}

src/cell.h

@@ -295,5 +295,6 @@ void cell_check_drift_point(struct cell *c, void *data);
 int cell_is_drift_needed(struct cell *c, const struct engine *e);
 int cell_unskip_tasks(struct cell *c, struct scheduler *s);
 void cell_set_super(struct cell *c, struct cell *super);
+void cell_set_ti_old(struct cell *c, int ti_current);
 
 #endif /* SWIFT_CELL_H */

src/runner.c

@@ -838,6 +838,17 @@ static void runner_do_drift(struct cell *c, struct engine *e, int drift) {
       /* Now, get the maximal particle motion from its square */
       dx_max = sqrtf(dx2_max);
 
+      /* Set ti_old on the sub-cells */
+      cell_set_ti_old(c, e->ti_current);
+
+      /* Need to recurse to unskip if need be */
+      for (int k = 0; k < 8; k++) {
+        if (c->progeny[k] != NULL) {
+          struct cell *cp = c->progeny[k];
+          runner_do_drift(cp, e, 0);
+        }
+      }
+
     } /* Check that we are actually going to move forward. */
 
     else {

src/runner_doiact.h

@@ -1989,6 +1989,10 @@ void DOSUB_SELF1(struct runner *r, struct cell *ci, int gettimer) {
   /* Should we even bother? */
   if (!cell_is_active(ci, r->e)) return;
 
+#ifdef SWIFT_DEBUG_CHECKS
+  cell_is_drifted(ci, r->e);
+#endif
+
   /* Recurse? */
   if (ci->split) {