Fix old bug in the original linking of gas and gparts read in from the ICs.

examples/main.c

@@ -679,6 +679,9 @@ int main(int argc, char *argv[]) {
       for (size_t k = 0; k < Ngpart; ++k)
         if (gparts[k].type == swift_type_gas) error("Linking problem");
     }
+
+    /* Check that the other links are correctly set */
+    part_verify_links(parts, gparts, sparts, Ngas, Ngpart, Nspart, 1);
 #endif
 
     /* Get the total number of particles across all nodes. */

src/common_io.c

@@ -708,7 +708,7 @@ void io_duplicate_hydro_gparts_mapper(void* restrict data, int Ngas,
     gparts[i + Ndm].type = swift_type_gas;
 
     /* Link the particles */
-    gparts[i + Ndm].id_or_neg_offset = -i;
+    gparts[i + Ndm].id_or_neg_offset = -(long long)(offset + i);
     parts[i].gpart = &gparts[i + Ndm];
   }
 }
@@ -764,7 +764,7 @@ void io_duplicate_hydro_sparts_mapper(void* restrict data, int Nstars,
     gparts[i + Ndm].type = swift_type_star;
 
     /* Link the particles */
-    gparts[i + Ndm].id_or_neg_offset = -i;
+    gparts[i + Ndm].id_or_neg_offset = -(long long)(offset + i);
     sparts[i].gpart = &gparts[i + Ndm];
   }
 }

src/scheduler.c

@@ -1435,7 +1435,8 @@ void scheduler_enqueue(struct scheduler *s, struct task *t) {
     switch (t->type) {
       case task_type_self:
       case task_type_sub_self:
-        if (t->subtype == task_subtype_grav || t->subtype == task_subtype_external_grav)
+        if (t->subtype == task_subtype_grav ||
+            t->subtype == task_subtype_external_grav)
           qid = t->ci->super_gravity->owner;
         else
           qid = t->ci->super_hydro->owner;