Get Number of Contact Pairs

RELEASE-NOTES.md

@@ -37,6 +37,7 @@ Changelog](http://keepachangelog.com/en/1.0.0/).
 - Added a lot more 2D and 3D computational geometry unit tests covering more face/edge configurations
 - Support for linear triangle meshes in Tribol's SINGLE_MORTAR method (exact Jacobians through Enzyme or approximate
   Jacobians)
+- Added API function to get the number of active contact pairs on a coupling scheme.
 
 ### Changed
 - Return negative timestep vote for non-null meshes with null velocity pointers.

src/tribol/interface/tribol.cpp

@@ -826,6 +826,27 @@ void setInterfacePairs( IndexT cs_id, IndexT numPairs, IndexT const* const pairI
 
 }  // end setInterfacePairs()
 
+//------------------------------------------------------------------------------
+int getNumberOfContactPairsOnRank( IndexT cs_id )
+{
+  auto cs = CouplingSchemeManager::getInstance().findData( cs_id );
+  return cs->getNumActivePairs();
+}
+
+//------------------------------------------------------------------------------
+int getTotalNumberOfContactPairs( IndexT cs_id )
+{
+  auto cs = CouplingSchemeManager::getInstance().findData( cs_id );
+  if ( cs != nullptr ) {
+    auto comm = cs->getProblemComm();
+    int local_num_pairs = cs->getNumActivePairs();
+    int global_num_pairs = 0;
+    MPI_Allreduce( &local_num_pairs, &global_num_pairs, 1, MPI_INT, MPI_SUM, comm );
+    return global_num_pairs;
+  }
+  return 0;
+}
+
 //------------------------------------------------------------------------------
 int update( int cycle, RealT t, RealT& dt )
 {

src/tribol/interface/tribol.hpp

@@ -493,6 +493,26 @@ void setInterfacePairs( IndexT cs_id, IndexT numPairs, IndexT const* mesh_id1, I
                         IndexT const* pairIndex1, IndexT const* mesh_id2, IndexT const* pairType2,
                         IndexT const* pairIndex2 );
 
+/*!
+ * \brief Get the number of contact pairs on rank for the given coupling scheme
+ *
+ * \param [in] cs_id coupling scheme id
+ *
+ * \return the number of contact pairs on rank
+ */
+int getNumberOfContactPairsOnRank( IndexT cs_id );
+
+/*!
+ * \brief Get the total number of contact pairs across all ranks for the given coupling scheme
+ *
+ * \param [in] cs_id coupling scheme id
+ *
+ * \return the total number of contact pairs across all rank
+ *
+ * \note this routine only works on host
+ */
+int getTotalNumberOfContactPairs( IndexT cs_id );
+
 /*!
  * \brief Computes the contact response at the given cycle.
  *