[MOAB-dev] r3380 - MOAB/trunk

[kraftche at cae.wisc.edu]

Author: kraftche
Date: 2009-11-20 13:12:44 -0600 (Fri, 20 Nov 2009)
New Revision: 3380

Modified:
   MOAB/trunk/MBSkinner.cpp
Log:
o Change skinner to use now faster bit tags.  Results in better performance
  when skinning subsets of the mesh at the cost of slightly worse performance
  when skinning the entire mesh.  Could probably be even better if the
  bit tag code were cleaned up and optimized a bit.

o Now that bit tag default values work correctly, skip allocation of tag
  data for bit tags when skinning the entire mesh.




Modified: MOAB/trunk/MBSkinner.cpp
===================================================================
--- MOAB/trunk/MBSkinner.cpp	2009-11-20 19:00:50 UTC (rev 3379)
+++ MOAB/trunk/MBSkinner.cpp	2009-11-20 19:12:44 UTC (rev 3380)
@@ -1002,11 +1002,6 @@
   return result;
 }
 
-// Bit tag uses less memory, but is slower.  Probably
-// because we have to query one entity at a time.
-// -- j.kraftcheck 2009-11-10
-const bool use_bit_tag = false;
-
 MBErrorCode MBSkinner::find_skin_vertices( const MBRange& entities,
                                            MBRange* skin_verts,
                                            MBRange* skin_elems,
@@ -1022,23 +1017,33 @@
   if (dim < 1 || dim > 3 || !entities.all_of_dimension(dim))
     return MB_TYPE_OUT_OF_RANGE;
   
-    // create a bit tag for use in a) tagging skin vertices, and 
-    // b) fast intersection with input entities range. 
+    // are we skinning all entities
+  size_t count = entities.size();
+  int num_total;
+  rval = thisMB->get_number_entities_by_dimension( 0, dim, num_total );
+  if (MB_SUCCESS != rval)
+    return rval;
+  bool all = (count == (size_t)num_total);
+  
+    // Create a bit tag for fast intersection with input entities range. 
+    // If we're skinning all the entities in the mesh, we really don't
+    // need the tag.  To save memory, just create it with a default value
+    // of one and don't set it.  That way MOAB will return 1 for all 
+    // entities.
   MBTag tag;
-  char bit = 0;
-  rval = thisMB->tag_create( NULL, 1, use_bit_tag ? MB_TAG_BIT : MB_TAG_DENSE, tag, &bit );
+  char bit = all ? 1 : 0;
+  rval = thisMB->tag_create( NULL, 1, MB_TAG_BIT, tag, &bit );
   if (MB_SUCCESS != rval)
     return rval;
   
     // tag all entities in input range
-  size_t count = entities.size();
-  char* vect = new char[count];
-  memset( vect, 1, count );
-  rval = thisMB->tag_set_data( tag, entities, vect );
-  delete [] vect;
-  if (MB_SUCCESS != rval) {
-    thisMB->tag_delete(tag);
-    return rval;
+  if (!all) {
+    std::vector<unsigned char> vect(count, 1);
+    rval = thisMB->tag_set_data( tag, entities, &vect[0] );
+    if (MB_SUCCESS != rval) {
+      thisMB->tag_delete(tag);
+      return rval;
+    }
   }
   
   switch (dim) {