p4est_bits: add p4est_quadrant_root

Previously we were generating a root quadrant by calling
p4est_quadrant_set_morton (q, 0, 0), which is less immediate.

src/p4est_bits.c

@@ -1221,6 +1221,21 @@ p4est_quadrant_enlarge_last (const p4est_quadrant_t * a, p4est_quadrant_t * q)
 #endif
 }
 
+void
+p4est_quadrant_root (p4est_quadrant_t *root)
+{
+  P4EST_ASSERT (root != NULL);
+
+  root->x = 0;
+  root->y = 0;
+#ifdef P4_TO_P8
+  root->z = 0;
+#endif
+  root->level = 0;
+
+  P4EST_ASSERT (p4est_quadrant_is_valid (root));
+}
+
 void
 p4est_quadrant_ancestor (const p4est_quadrant_t * q,
                          int level, p4est_quadrant_t * r)
@@ -2212,7 +2227,7 @@ p4est_coordinates_transform_corner (p4est_qcoord_t coords[], int corner)
 #endif
 
 #ifdef P4EST_ENABLE_DEBUG
-  p4est_quadrant_set_morton (&root, 0, 0);
+  p4est_quadrant_root (&root);
   p4est_quadrant_corner_coordinates (&root, corner, rcoords);
   P4EST_ASSERT (rcoords[0] == coords[0]);
   P4EST_ASSERT (rcoords[1] == coords[1]);

src/p4est_bits.h

@@ -378,6 +378,14 @@ void                p4est_quadrant_enlarge_first (const p4est_quadrant_t * a,
 void                p4est_quadrant_enlarge_last (const p4est_quadrant_t * a,
                                                  p4est_quadrant_t * q);
 
+/** Generate the root quadrant of any tree.
+ * \param [out] root    Quadrant structure's coordinates and level are set.
+ *                      As with all other functions that generate or
+ *                      modify quadrants, the other bits of the structured
+ *                      data type are not touched at all.
+ */
+void                p4est_quadrant_root (p4est_quadrant_t *root);
+
 /** Compute the ancestor of a quadrant at a given level.
  * \param [in]  q       Input quadrant.
  * \param [in]  level   A smaller level than q.

src/p4est_points.c

@@ -303,7 +303,7 @@ p4est_new_points (sc_MPI_Comm mpicomm, p4est_connectivity_t * connectivity,
     /* determine largest possible last quadrant of this tree */
     if (jt < next_tree) {
       p4est_quadrant_last_descendant (&a, &l, maxlevel);
-      p4est_quadrant_set_morton_ext128 (&b, 0, &zero);
+      p4est_quadrant_root (&b);
       p4est_quadrant_last_descendant (&b, &b, maxlevel);
       if (p4est_quadrant_is_equal (&l, &b)) {
         onlyone = 1;

src/p4est_search.c

@@ -768,7 +768,7 @@ p4est_search_local (p4est_t * p4est,
     tquadrants = &tree->quadrants;
 
     /* the recursion shrinks the search quadrant whenever possible */
-    p4est_quadrant_set_morton (&root, 0, 0);
+    p4est_quadrant_root (&root);
     p4est_local_recursion (rec, &root, tquadrants, NULL);
   }
 }
@@ -1033,7 +1033,7 @@ p4est_search_reorder (p4est_t * p4est, int skip_levels,
     for (tt = p4est->first_local_tree; tt <= p4est->last_local_tree; ++tt) {
       rit = tt - p4est->first_local_tree;
       proot = (p4est_quadrant_t *) sc_array_index (tquadrants, rit);
-      p4est_quadrant_set_morton (proot, 0, 0);
+      p4est_quadrant_root (proot);
       proot->p.piggy1.which_tree = tt;
       *(p4est_topidx_t *) sc_array_index (root_indices, rit) = rit;
     }
@@ -1073,7 +1073,7 @@ p4est_search_reorder (p4est_t * p4est, int skip_levels,
     tquadrants = &tree->quadrants;
 
     /* the recursion shrinks the search quadrant whenever possible */
-    p4est_quadrant_set_morton (&root, 0, 0);
+    p4est_quadrant_root (&root);
     p4est_reorder_recursion (rec, &root, tquadrants, NULL);
   }
 
@@ -1209,7 +1209,7 @@ static int          p4est_traverse_is_valid_tree
   P4EST_ASSERT (0 <= which_tree && which_tree < num_trees);
   P4EST_ASSERT (0 <= pfirst && pfirst <= plast && plast < num_procs);
 
-  p4est_quadrant_set_morton (&root, 0, 0);
+  p4est_quadrant_root (&root);
 
   return p4est_traverse_is_valid_quadrant
     (gfp, num_procs, num_trees, which_tree, &root, pfirst, plast);
@@ -1538,7 +1538,7 @@ void                p4est_search_partition_internal
   rec->point_fn = point_fn;
   rec->points = points;
   rec->position_array = &position_array;
-  p4est_quadrant_set_morton (&root, 0, 0);
+  p4est_quadrant_root (&root);
   for (pfirst = 0, tt = 0; tt < num_trees; pfirst = pnext, ++tt) {
     /* pfirst is the first processor indexed for this tree */
     rec->which_tree = root.p.which_tree = tt;
@@ -1909,7 +1909,7 @@ p4est_search_all (p4est_t * p4est,
   rec->point_fn = point_fn;
   rec->points = points;
   rec->position_array = &position_array;
-  p4est_quadrant_set_morton (&root, 0, 0);
+  p4est_quadrant_root (&root);
   for (pfirst = 0, tt = 0; tt < num_trees; pfirst = pnext, ++tt) {
     /* pfirst is the first processor indexed for this tree */
     rec->which_tree = root.p.which_tree = tt;

src/p4est_to_p8est.h

@@ -368,6 +368,7 @@
 #define p4est_quadrant_is_first_last    p8est_quadrant_is_first_last
 #define p4est_quadrant_enlarge_first    p8est_quadrant_enlarge_first
 #define p4est_quadrant_enlarge_last     p8est_quadrant_enlarge_last
+#define p4est_quadrant_root             p8est_quadrant_root
 #define p4est_quadrant_ancestor         p8est_quadrant_ancestor
 #define p4est_quadrant_parent           p8est_quadrant_parent
 #define p4est_quadrant_sibling          p8est_quadrant_sibling

src/p8est_bits.h

@@ -408,6 +408,14 @@ void                p8est_quadrant_enlarge_first (const p8est_quadrant_t * a,
 void                p8est_quadrant_enlarge_last (const p8est_quadrant_t * a,
                                                  p8est_quadrant_t * q);
 
+/** Generate the root quadrant of any tree.
+ * \param [out] root    Quadrant structure's coordinates and level are set.
+ *                      As with all other functions that generate or
+ *                      modify quadrants, the other bits of the structured
+ *                      data type are not touched at all.
+ */
+void                p8est_quadrant_root (p8est_quadrant_t *root);
+
 /** Compute the ancestor of a quadrant at a given level.
  * \param [in]  q       Input quadrant.
  * \param [in]  level   A smaller level than q.