minor

Simplify Mesh::GetFaceElements

examples/face_neigbors.cpp

@@ -0,0 +1,65 @@
+
+#include "mfem.hpp"
+#include <fstream>
+#include <iostream>
+
+using namespace std;
+using namespace mfem;
+
+
+int main(int argc, char *argv[])
+{
+   // 1. Parse command-line options.
+   const char *mesh_file = "../data/inline-quad.mesh";
+   bool vis = true;
+   OptionsParser args(argc, argv);
+   args.AddOption(&vis, "-vis", "--visualization", "-no-vis",
+                  "--no-visualization",
+                  "Enable or disable GLVis visualization.");
+   args.Parse();
+   if (!args.Good())
+   {
+      args.PrintUsage(cout);
+      return 1;
+   }
+   args.PrintOptions(cout);
+
+   Mesh mesh(mesh_file, 1, 1);
+
+   Array<int> ref_elems(1);
+   ref_elems = 2;
+   mesh.GeneralRefinement(ref_elems,-1,0);
+   ref_elems = 5;
+   mesh.GeneralRefinement(ref_elems,-1,0);
+
+   Array<int> faces({0,10,26,28,29});
+
+   for (int i = 0; i<faces.Size(); i++)
+   {
+      Array<int> elems;
+      mesh.GetFaceElements(faces[i],elems);
+
+      if (vis)
+      {
+         char vishost[] = "localhost";
+         int  visport   = 19916;
+         socketstream patch_sock(vishost, visport);
+         L2_FECollection fec(1,mesh.Dimension());
+         FiniteElementSpace fes(&mesh,&fec);
+         GridFunction vis_gf(&fes);
+         vis_gf = 0.0;
+         Array<int> dofs;
+         for (int i=0; i<elems.Size(); i++)
+         {
+            int el = elems[i];
+            fes.GetElementDofs(el, dofs);
+            vis_gf.SetSubVector(dofs,1.0);
+         }
+         patch_sock.precision(8);
+         patch_sock << "solution\n" << mesh << vis_gf <<
+                    "keys rRmjnppppp\n" << flush;
+      }
+   }
+
+   return 0;
+}

mesh/mesh.cpp

@@ -1410,6 +1410,59 @@ void Mesh::GetFaceInfos(int Face, int *Inf1, int *Inf2, int *NCFace) const
    *NCFace = faces_info[Face].NCFace;
 }
 
+void Mesh::GetFaceAdjacentElements(int face, Array<int> & elems) const
+{
+   bool nonconforming_face = ncmesh && (faces_info[face].NCFace != -1);
+   MFEM_VERIFY(face < GetNumFaces(), "GetFaceAdjacentElements only implemented"
+               "for local faces.");
+   if (nonconforming_face) //nonconforming master
+   {
+      int nc_index = faces_info[face].NCFace;
+      const NCFaceInfo &nc_info = nc_faces_info[nc_index];
+      if (!nc_info.Slave)
+      {
+         const mfem::NCMesh::NCList &nc_list = ncmesh->GetNCList(Dim-1);
+         elems.Append(ncmesh->elements[nc_list.masters[nc_index].element].index);
+         int j_begin = nc_list.masters[nc_index].slaves_begin;
+         int j_end = nc_list.masters[nc_index].slaves_end;
+         for (int j = j_begin; j<j_end ; j++)
+         {
+            int fnum = nc_list.slaves[j].index;
+            if (fnum >= GetNumFaces())
+            {
+               const FaceInfo &face_info = faces_info[fnum];
+               elems.Append(GetNE() -1 -face_info.Elem2No);
+            }
+            else
+            {
+               elems.Append(ncmesh->elements[nc_list.slaves[j].element].index);
+            }
+         }
+         return;
+      }
+   }
+   //(i) conforming interior -
+   //(ii) conforming processor boundary
+   //(iii) true boundary -
+   //(iv) nonconforming interior slave -
+   //(v) nonconforming processor boundary with slave
+   {
+      const FaceInfo &face_info = faces_info[face];
+      elems.Append(face_info.Elem1No);
+      if (face_info.Elem2No >= 0)
+      {
+         elems.Append(face_info.Elem2No); //(i, iii, iv)
+      }
+      else
+      {
+         if (face_info.Elem2Inf >= 0)
+         {
+            elems.Append(GetNE()-1-face_info.Elem2No); //(ii, v)
+         }
+      }
+   }
+}
+
 Geometry::Type Mesh::GetFaceGeometry(int Face) const
 {
    switch (Dim)

mesh/mesh.hpp

@@ -1485,6 +1485,16 @@ public:
    void GetFaceInfos (int Face, int *Inf1, int *Inf2) const;
    void GetFaceInfos (int Face, int *Inf1, int *Inf2, int *NCFace) const;
 
+   /** Return all elements adjacent to the given Face
+    *  Returns local (to the processor element no)
+    *  if local_no >= num_elems it num_elements + ghost element index 
+    *  (This can be used in pmesh.GetFaceNbrElementTransformation)
+    */
+   void GetFaceAdjacentElements(int Face, Array<int> & elems) const;
+
+//    Returns global (unique) element numbers
+//    void GetFaceAdjacentElementsGlobal(int Face, Array<int> & elems) const;
+
    /// Deprecated in favor of Mesh::GetFaceGeometry
    MFEM_DEPRECATED Geometry::Type GetFaceGeometryType(int Face) const
    { return GetFaceGeometry(Face); }