Feature triangle: store local first child on rank

src/p4est_tnodes.c

@@ -1336,6 +1336,7 @@ p4est_tnodes_new_Q2_P1 (p4est_t *p4est, p4est_lnodes_t * lnodes,
   tnodes = P4EST_ALLOC_ZERO (p4est_tnodes_t, 1);
   tnodes->lnodes = lnodes;
   tnodes->lnodes_owned = 0;
+  tnodes->local_first_child = -1;
 
   /* prepare coordinate allocation */
   tnodes->coordinates = sc_array_new (3 * sizeof (double));
@@ -1389,14 +1390,22 @@ p4est_tnodes_new_Q2_P1 (p4est_t *p4est, p4est_lnodes_t * lnodes,
   tnodes->local_element_offset[0] = 0;
   for (el = 0; el < ne; enodes += P4EST_INSUL, ++el) {
 
-    if (construction_flags & P4EST_TNODES_STORE_LEVELS) {
+    if ((construction_flags & P4EST_TNODES_STORE_LEVELS) || tree == NULL) {
       /* track tree number and quadrant level to find element level */
       P4EST_ASSERT (el <= ecumul);
       if (el == ecumul) {
+        p4est_quadrant_t   *quadrant;
+
+        /* enter next local tree */
         tree = p4est_tree_array_index (p4est->trees, ++tt);
         ecumul += (p4est_locidx_t) tree->quadrants.elem_count;
         P4EST_ASSERT (el < ecumul);
+        if (tnodes->local_first_child < 0) {
+          quadrant = p4est_quadrant_array_index (&tree->quadrants, 0);
+          tnodes->local_first_child = p4est_quadrant_child_id (quadrant);
+        }
       }
+      P4EST_ASSERT (tree != NULL);
 
       /* retrieve and assign proper element level */
       level = (p4est_quadrant_array_index
@@ -1658,6 +1667,8 @@ p4est_tnodes_new_Q2_P1 (p4est_t *p4est, p4est_lnodes_t * lnodes,
 
   /* synchronize simplex counts in parallel */
   p4est_tnodes_simplex_counts (p4est, tnodes);
+  P4EST_ASSERT ((tnodes->local_first_child == -1) ==
+                (tnodes->local_first_tree > tnodes->local_last_tree));
   P4EST_GLOBAL_PRODUCTIONF
     ("Done " P4EST_STRING "_tnodes_new_Q2 with %lld global simplices\n",
      (long long) tnodes->global_tcount);

src/p4est_tnodes.h

@@ -47,10 +47,12 @@ typedef enum        p4est_tnodes_flags
   /** Generate geometric coordinates for nodes on the tree boundary.
    * Since the \ref p4est_connectivity may be periodic, the same lnode
    * entry (see \ref p4est_lnodes) may be referenced from more than one
-   * coordinate location.  If periodicity is not expected, this flag is not
-   * needed.  Otherwise, setting it disambiguates the coordinates between
-   * multiple instances for the same lnode entry.  This enables for example
-   * the visualization of the periodic unit square as a factual square. */
+   * coordinate location.  If periodicity is not expected, and the geometry
+   * is continuous across tree boundaries, this flag is not needed.
+   * Otherwise, setting it disambiguates the coordinates between multiple
+   * instances for the same lnode entry.  This enables for example the
+   * visualization of the periodic unit square as a factual square, or the
+   * setup of geometries that are artificially mapped for display. */
   P4EST_TNODES_COORDS_SEPARATE = 0x01,
 
   /** Allocate and fill local_element_level array in \ref p4est_tnodes. */
@@ -96,6 +98,8 @@ typedef struct p4est_tnodes
    * Array may be NULL if the information is not provided. */
   int8_t             *local_element_level;
 
+  int                 local_first_child;        /**< First child id on
+                                             process, or -1 if empty. */
   p4est_topidx_t      local_first_tree; /**< First local tree on process,
                                              -1 if process has no elements. */
   p4est_topidx_t      local_last_tree;  /**< Last local tree on process,

src/p8est_tnodes.h

@@ -45,12 +45,14 @@ typedef enum        p8est_tnodes_flags
   P8EST_TNODES_FLAGS_NONE = 0,
 
   /** Generate geometric coordinates for nodes on the tree boundary.
-   * Since the \ref p4est_connectivity may be periodic, the same lnode
-   * entry (see \ref p4est_lnodes) may be referenced from more than one
-   * coordinate location.  If periodicity is not expected, this flag is not
-   * needed.  Otherwise, setting it disambiguates the coordinates between
-   * multiple instances for the same lnode entry.  This enables for example
-   * the visualization of the periodic unit square as a factual square. */
+   * Since the \ref p8est_connectivity may be periodic, the same lnode
+   * entry (see \ref p8est_lnodes) may be referenced from more than one
+   * coordinate location.  If periodicity is not expected, and the geometry
+   * is continuous across tree boundaries, this flag is not needed.
+   * Otherwise, setting it disambiguates the coordinates between multiple
+   * instances for the same lnode entry.  This enables for example the
+   * visualization of the periodic unit square as a factual square, or the
+   * setup of geometries that are artificially mapped for display. */
   P8EST_TNODES_COORDS_SEPARATE = 0x01,
 
   /** Allocate and fill local_element_level array in \ref p8est_tnodes. */
@@ -86,6 +88,8 @@ typedef struct p8est_tnodes
    * Array may be NULL if the information is not provided. */
   int8_t             *local_element_level;
 
+  int                 local_first_child;        /**< First child id on
+                                             process, or -1 if empty. */
   p4est_topidx_t      local_first_tree; /**< First local tree on process,
                                              -1 if process has no elements. */
   p4est_topidx_t      local_last_tree;  /**< Last local tree on process,