RefinementManager3d.cc

#include "RefinementManager.h"
#include "Mesh.h"
#include "Traverse.h"
#include "ElInfo.h"
#include "DOFAdmin.h"
#include "AdaptStationary.h"
#include "AdaptInstationary.h"
#include "FixVec.h"
#include "RCNeighbourList.h"
#include "ProblemStatBase.h"
#include "DOFIndexed.h"
#include "Projection.h"
#include "DOFVector.h"
#include "PeriodicBC.h"
#include "VertexVector.h"

namespace AMDiS {

  void RefinementManager3d::bisectTetrahedron(RCNeighbourList* ref_list, 
					      int index,
					      DegreeOfFreedom* dof[3],
					      DegreeOfFreedom *edge[2])
  {
    Tetrahedron *el = 
      dynamic_cast<Tetrahedron*>(const_cast<Element*>(ref_list->getElement(index)));
    Tetrahedron *child[2];
    int el_type = ref_list->getType(index);

    child[0] = dynamic_cast<Tetrahedron*>(mesh->createNewElement(el));
    child[1] = dynamic_cast<Tetrahedron*>(mesh->createNewElement(el));
  
    int mark = max(0, el->getMark() - 1);
    child[0]->setMark(mark);
    child[1]->setMark(mark);
    el->setMark(0);

    /****************************************************************************/
    /*  transfer hidden data from parent to children                            */
    /****************************************************************************/

    el->refineElementData(child[0], child[1], el_type);

    el->setFirstChild(child[0]);
    el->setSecondChild(child[1]);

    if (child[0]->getMark() > 0)
      doMoreRecursiveRefine = true;

    int n_vertices = mesh->getGeo(VERTEX);
    child[0]->setDof(n_vertices - 1, dof[0]);
    child[1]->setDof(n_vertices - 1, dof[0]);

    for (int i = 0; i < n_vertices - 1; i++) {
      child[0]->
	setDof(i, const_cast<int*>(el->getDof(Tetrahedron::childVertex[el_type][0][i])));
      child[1]->
	setDof(i, const_cast<int*>(el->getDof(Tetrahedron::childVertex[el_type][1][i])));
    }
    /****************************************************************************/
    /*  there is one more leaf element and two more hierachical elements        */
    /****************************************************************************/

    mesh->incrementNumberOfLeaves(1);
    mesh->incrementNumberOfElements(2);

    /****************************************************************************/
    /* first set those dof pointers for higher order without neighbour          */
    /* information                                                              */
    /****************************************************************************/

    if (mesh->getNumberOfDofs(EDGE)) {
      int node = mesh->getNode(EDGE);

      /****************************************************************************/
      /*  set pointers to those dof's that are handed on from the parant          */
      /****************************************************************************/
      
      child[0]->
	setDof(node, 
	       const_cast<int*>(el->getDof(node + Tetrahedron::childEdge[el_type][0][0])));
      child[1]->
	setDof(node, 
	       const_cast<int*>(el->getDof(node + Tetrahedron::childEdge[el_type][1][0])));
      child[0]->
	setDof(node + 1, 
	       const_cast<int*>(el->getDof(node + Tetrahedron::childEdge[el_type][0][1])));
      child[1]->
	setDof(node + 1, 
	       const_cast<int*>(el->getDof(node + Tetrahedron::childEdge[el_type][1][1])));
      child[0]->
	setDof(node + 3, 
	       const_cast<int*>(el->getDof(node + Tetrahedron::childEdge[el_type][0][3])));
      child[1]->
	setDof(node + 3, 
	       const_cast<int*>(el->getDof(node + Tetrahedron::childEdge[el_type][1][3])));
      
      /****************************************************************************/
      /*  adjust pointers to the dof's in the refinement edge                     */
      /****************************************************************************/
      
      if (el->getDof(0) == edge[0]) {
	child[0]->setDof(node + 2, dof[1]);
	child[1]->setDof(node + 2, dof[2]);
      } else {
	child[0]->setDof(node + 2, dof[2]);
	child[1]->setDof(node + 2, dof[1]);
      }
    }
    
    if (mesh->getNumberOfDofs(FACE)) {
      int node = mesh->getNode(FACE);    
      
      /****************************************************************************/
      /*  set pointers to those dof's that are handed on from the parant          */
      /****************************************************************************/
      
      child[0]->setDof(node + 3, const_cast<int*>(el->getDof(node + 1)));
      child[1]->setDof(node + 3, const_cast<int*>(el->getDof(node + 0)));
      
      /****************************************************************************/
      /*  get new dof for the common face of child0 and child1                    */
      /****************************************************************************/
      
      DegreeOfFreedom *newDOF = mesh->getDof(FACE);
      child[0]->setDof(node, static_cast<int*>(newDOF));
      child[1]->setDof(node, static_cast<int*>(newDOF));
    }
    
    if (mesh->getNumberOfDofs(CENTER)) {
      int node = mesh->getNode(CENTER);
      child[0]->setDof(node, const_cast<int*>(mesh->getDof(CENTER)));
      child[1]->setDof(node, const_cast<int*>(mesh->getDof(CENTER)));
    }

    if (mesh->getNumberOfDofs(EDGE) || mesh->getNumberOfDofs(FACE))
      fillPatchConnectivity(ref_list, index);
  }


  void RefinementManager3d::fillPatchConnectivity(RCNeighbourList* ref_list, 
						  int index)
  {
    FUNCNAME("RefinementManager3d::fillPatchConnectivity");

    Element *el = ref_list->getElement(index), *neigh;
    int el_type = ref_list->getType(index);
    int n_type = 0;
    int dir, adjc, i, j, i_neigh, j_neigh;
    int node0, node1, oppVertex = 0;

    for (dir = 0; dir < 2; dir++) {
      neigh = ref_list->getNeighbourElement(index, dir);
      if (neigh) {
	n_type = ref_list->getType(ref_list->getNeighbourNr(index, dir));
	oppVertex = ref_list->getOppVertex(index, dir);
      }

      if (!neigh || neigh->isLeaf()) {

	/****************************************************************************/
	/*  get new dof's in the midedge of the face of el and for the two midpoints*/
	/*  of the sub-faces. If face is an interior face those pointers have to be */
	/*  adjusted by the neighbour element also (see below)                      */
	/****************************************************************************/

	if (mesh->getNumberOfDofs(EDGE)) {
	  node0 = node1 = mesh->getNode(EDGE);
	  node0 += Tetrahedron::nChildEdge[el_type][0][dir];
	  node1 += Tetrahedron::nChildEdge[el_type][1][dir];
	  DegreeOfFreedom *newDOF = mesh->getDof(EDGE);
	  (const_cast<Element*>(el->getFirstChild()))->setDof(node0, newDOF);
	  (const_cast<Element*>(el->getSecondChild()))->setDof(node1, newDOF);
	}
	if (mesh->getNumberOfDofs(FACE)) {
	  node0 = mesh->getNode(FACE) + Tetrahedron::nChildFace[el_type][0][dir];
	  (const_cast<Element*>(el->getFirstChild()))->setDof(node0, mesh->getDof(FACE));
	  node1 = mesh->getNode(FACE) + Tetrahedron::nChildFace[el_type][1][dir];
	  (const_cast<Element*>(el->getSecondChild()))->setDof(node1, mesh->getDof(FACE));
	}
      } else {     /*   if (!neigh  ||  !neigh->child[0])                         */
	/****************************************************************************/
	/*  interior face and neighbour has been refined, look for position at the  */
	/*  refinement edge                                                         */
	/****************************************************************************/
      
	if (el->getDof(0) == neigh->getDof(0)) {
	  /****************************************************************************/
	  /* same position at refinement edge                                         */
	  /****************************************************************************/
	  adjc = 0;
	} else {
	  /****************************************************************************/
	  /* different position at refinement edge                                    */
	  /****************************************************************************/
	  adjc = 1;
	}

	for (i = 0; i < 2; i++) {
	  j = Tetrahedron::adjacentChild[adjc][i];

	  i_neigh = Tetrahedron::nChildFace[el_type][i][dir];
	  j_neigh = Tetrahedron::nChildFace[n_type][j][oppVertex - 2];

	  /****************************************************************************/
	  /*  adjust dof pointer in the edge in the common face of el and neigh and   */
	  /*  the dof pointer in the sub-face child_i-child_j (allocated by neigh!)   */
	  /****************************************************************************/

	  if (mesh->getNumberOfDofs(EDGE)) {
	    node0 = mesh->getNode(EDGE) + Tetrahedron::nChildEdge[el_type][i][dir];
	    node1 = mesh->getNode(EDGE) + Tetrahedron::nChildEdge[n_type][j][oppVertex - 2];

	    TEST_EXIT_DBG(neigh->getChild(j)->getDof(node1))
	      ("no dof on neighbour %d at node %d\n", 
	       neigh->getChild(j)->getIndex(), node1);

	    (const_cast<Element*>(el->getChild(i)))->
	      setDof(node0, const_cast<int*>(neigh->getChild(j)->getDof(node1)));
	  }
	  if (mesh->getNumberOfDofs(FACE)) {
	    node0 = mesh->getNode(FACE) + i_neigh;
	    node1 = mesh->getNode(FACE) + j_neigh;

	    TEST_EXIT_DBG(neigh->getChild(j)->getDof(node1))
	      ("No DOF on neighbour %d at node %d!\n",
	       neigh->getChild(j)->getIndex(), node1);

	    (const_cast<Element*>(el->getChild(i)))->
	      setDof(node0, const_cast<int*>(neigh->getChild(j)->getDof(node1)));
	  }

	}  /*   for (i = 0; i < 2; i++)                                       */
      }    /*   else of   if (!neigh  ||  !neigh->child[0])                   */
    }      /*   for (dir = 0; dir < 2; dir++)                                 */
  }


  int RefinementManager3d::newCoordsFct(ElInfo *el_info)
  {
    Element *el = el_info->getElement();
    DegreeOfFreedom *edge[2];
    ElInfo *elinfo = el_info;
    int dow = Global::getGeo(WORLD);
    Projection *projector = el_info->getProjection(0);

    if (!projector || projector->getType() != VOLUME_PROJECTION)
      projector = el_info->getProjection(4);    

    if (el->getFirstChild() && projector && (!el->isNewCoordSet())) {
      WorldVector<double> *new_coord = new WorldVector<double>;

      for (int j = 0; j < dow; j++)
	(*new_coord)[j] = (el_info->getCoord(0)[j] + el_info->getCoord(1)[j]) * 0.5;

      projector->project(*new_coord);

      el->setNewCoord(new_coord);
      /****************************************************************************/
      /*  now, information should be passed on to patch neighbours...             */
      /*  get the refinement patch                                                */
      /****************************************************************************/
      refList->setElement(0, el);
      refList->setElType(0, el_info->getType());
      int n_neigh = 1;

      for (int i = 0; i < 2; i++)
	edge[i] = const_cast<int*>(el_info->getElement()->getDof(i));

      if (getRefinePatch(&elinfo, edge, 0, refList, &n_neigh)) {
	// Domain's boundary was reached while looping around the refinement edge.

	getRefinePatch(&elinfo, edge, 1, refList, &n_neigh);
      }

      for (int i = 1; i < n_neigh; i++) {            /* start with 1, as list[0]=el */
	TEST(!refList->getElement(i)->isNewCoordSet())
	  ("non-nil new_coord in el %d ref_list[%d] el %d (n_neigh=%d)\n",
	   el->getIndex(), i, refList->getElement(i)->getIndex(), n_neigh);
	
	refList->getElement(i)->setNewCoord(el->getNewCoord());
      }
    }

    return 0;
  }


  void RefinementManager3d::setNewCoords(int macroEl)
  {
    if (refList)
      delete refList;
 
    refList = new RCNeighbourList(mesh->getMaxEdgeNeigh());
    ElInfo *elInfo;

    if (macroEl == -1)
      elInfo = stack->traverseFirst(mesh, -1, 
				    Mesh::CALL_EVERY_EL_PREORDER | 
				    Mesh::FILL_BOUND | Mesh::FILL_COORDS | 
				    Mesh::FILL_NEIGH);
    else
      elInfo = stack->traverseFirstOneMacro(mesh, macroEl, -1,
					    Mesh::CALL_EVERY_EL_PREORDER | 
					    Mesh::FILL_BOUND | Mesh::FILL_COORDS | 
					    Mesh::FILL_NEIGH);
    

    while (elInfo) {
      newCoordsFct(elInfo);
      elInfo = stack->traverseNext(elInfo);
    }
  }


  DegreeOfFreedom RefinementManager3d::refinePatch(DegreeOfFreedom *edge[2], 
						   RCNeighbourList* refineList,
						   int n_neigh, bool bound)
  {
    Tetrahedron *el = 
      dynamic_cast<Tetrahedron*>(const_cast<Element*>(refineList->getElement(0)));
    /* first element in the list */
    DegreeOfFreedom *dof[3] = {NULL, NULL, NULL};

    /****************************************************************************/
    /*  get new dof's in the refinement edge                                    */
    /****************************************************************************/

    dof[0] = mesh->getDof(VERTEX);
    mesh->incrementNumberOfVertices(1);
  
    if (mesh->getNumberOfDofs(EDGE)) {
      dof[1] = mesh->getDof(EDGE);
      dof[2] = mesh->getDof(EDGE);
    }

    for (int i = 0; i < n_neigh; i++)
      bisectTetrahedron(refineList, i, dof, edge);

    /****************************************************************************/
    /*  if there are functions to interpolate data to the finer grid, do so     */
    /****************************************************************************/
    int iadmin;
    int nrAdmin = mesh->getNumberOfDOFAdmin();
    for (iadmin = 0; iadmin < nrAdmin; iadmin++) {
      std::list<DOFIndexedBase*>::iterator it;
      DOFAdmin* admin = const_cast<DOFAdmin*>(&mesh->getDofAdmin(iadmin));
      std::list<DOFIndexedBase*>::iterator end = admin->endDOFIndexed();
      for (it = admin->beginDOFIndexed(); it != end; it++)
	(*it)->refineInterpol(*refineList, n_neigh);
    }

    if (!mesh->queryCoarseDOFs()) {
      /****************************************************************************/
      /*  if there should be no dof information on interior leaf elements remove  */
      /*  dofs from edges, faces and the centers of parents                       */
      /****************************************************************************/
      if (mesh->getNumberOfDofs(EDGE)) {
	/****************************************************************************/
	/*  remove dof of the midpoint of the common refinement edge                */
	/****************************************************************************/

	el = dynamic_cast<Tetrahedron*>(const_cast<Element*>(refineList->getElement(0)));
	mesh->freeDof(const_cast<int*>(el->getDof(mesh->getNode(EDGE))), EDGE);
      }
      
      if (mesh->getNumberOfDofs(EDGE) || 
	  mesh->getNumberOfDofs(FACE) ||
	  mesh->getNumberOfDofs(CENTER)) {
	for (int i = 0; i < n_neigh; i++)
	  refineList->removeDOFParent(i);
      }
    }


    /****************************************************************************/
    /*  update the number of edges and faces; depends whether refinement edge   */
    /*  is a boundary edge or not                                               */
    /****************************************************************************/

    if (bound) {
      mesh->incrementNumberOfEdges(n_neigh + 2);
      mesh->incrementNumberOfFaces(2 * n_neigh + 1);
    } else {
      mesh->incrementNumberOfEdges(n_neigh + 1);
      mesh->incrementNumberOfFaces(2 * n_neigh);
    }
    
    return dof[0][0];
  }


  int RefinementManager3d::getRefinePatch(ElInfo **el_info, 
					  DegreeOfFreedom *edge[2], 
					  int direction,
					  RCNeighbourList* refineList, 
					  int *n_neigh)
  {
    FUNCNAME("RefinementManager3d::getRefinePatch()");

    int localNeighbour = 3 - direction;
    Tetrahedron *el = 
      dynamic_cast<Tetrahedron*>(const_cast<Element*>((*el_info)->getElement()));
    
    if ((*el_info)->getNeighbour(localNeighbour) == NULL)
      return 1;    
  
    int oppVertex = (*el_info)->getOppVertex(localNeighbour);
    int testIndex = (*el_info)->getNeighbour(localNeighbour)->getIndex();
    ElInfo *neighInfo = stack->traverseNeighbour3d((*el_info), localNeighbour);
    int neighElType = neighInfo->getType();

    TEST_EXIT_DBG(neighInfo->getElement()->getIndex() == testIndex)
      ("Should not happen!\n");

    Tetrahedron *neigh = 
      dynamic_cast<Tetrahedron*>(const_cast<Element*>(neighInfo->getElement())); 
    int vertices = mesh->getGeo(VERTEX);

    while (neigh != el) {
      // === Determine the common edge of the element and its neighbour. ===

      int edgeDof0, edgeDof1;
      for (edgeDof0 = 0; edgeDof0 < vertices; edgeDof0++)
	if (neigh->getDof(edgeDof0) == edge[0])
	  break;
      for (edgeDof1 = 0; edgeDof1 < vertices; edgeDof1++)
	if (neigh->getDof(edgeDof1) == edge[1])
	  break;

      if (edgeDof0 > 3 || edgeDof1 > 3) {
	for (edgeDof0 = 0; edgeDof0 < vertices; edgeDof0++)
	  if (mesh->associated(neigh->getDof(edgeDof0, 0), edge[0][0]))  
	    break;
	for (edgeDof1 = 0; edgeDof1 < vertices; edgeDof1++)
	  if (mesh->associated(neigh->getDof(edgeDof1, 0), edge[1][0]))  
	    break;
	    
	if (edgeDof0 > 3 || edgeDof1 > 3) {
	  for (edgeDof0 = 0; edgeDof0 < vertices; edgeDof0++)
	    if (mesh->indirectlyAssociated(neigh->getDof(edgeDof0, 0), edge[0][0]))  
	      break;
	  for (edgeDof1 = 0; edgeDof1 < vertices; edgeDof1++)
	    if (mesh->indirectlyAssociated(neigh->getDof(edgeDof1, 0), edge[1][0]))  
	      break;
	    
	  TEST_EXIT_DBG(edgeDof0 < vertices && edgeDof1 < vertices)
 	    ("dof %d or dof %d not found on element %d with nodes (%d %d %d %d)\n", 
 	     edge[0][0], edge[1][0], neigh->getIndex(), neigh->getDof(0,0),
 	     neigh->getDof(1, 0), neigh->getDof(2, 0), neigh->getDof(3, 0));

	}
      }

      TEST_EXIT_DBG(edgeDof0 < vertices && edgeDof1 < vertices)
	("dof %d or dof %d not found on element %d with nodes (%d %d %d %d)\n", 
	 edge[0][0], edge[1][0], neigh->getIndex(), neigh->getDof(0, 0),
	 neigh->getDof(1, 0), neigh->getDof(2, 0), neigh->getDof(3, 0));

      int edgeNo = Tetrahedron::edgeOfDofs[edgeDof0][edgeDof1];

      if (edgeNo) {
	// Only 0 can be a compatible commen refinement edge. Thus, neigh has not 
	// a compatible refinement edge. Refine it first.

	neigh->setMark(max(neigh->getMark(), 1));

	neighInfo = refineFunction(neighInfo);

	// === Now, go to a child at the edge and determine the opposite vertex ===
	// === for  this child; continue the looping around the edge with this  ===
	// === element.                                                         ===
	
	neighInfo = stack->traverseNext(neighInfo);
	neighElType = neighInfo->getType();
	bool reverseMode = stack->getTraverseFlag().isSet(Mesh::CALL_REVERSE_MODE);
	
	switch (edgeNo) {
	case 1: 
	  if (reverseMode) {
	    neighInfo = stack->traverseNext(neighInfo);
	    neighElType = neighInfo->getType();
	  }
	    
	  oppVertex = (oppVertex == 1 ? 3 : 2);
	  break;
	case 2: 
	  if (reverseMode) {
	    neighInfo = stack->traverseNext(neighInfo);
	    neighElType = neighInfo->getType();
	  }

	  oppVertex = (oppVertex == 2 ? 1 : 3);
	  break;
	case 3: 
	  if (!reverseMode) {
	    neighInfo = stack->traverseNext(neighInfo);
	    neighElType = neighInfo->getType();
	  }

	  if (neighElType != 1)
	    oppVertex = (oppVertex == 0 ? 3 : 2);
	  else
	    oppVertex = (oppVertex == 0 ? 3 : 1);
	  break;
	case 4:
	  if (!reverseMode) {
	    neighInfo = stack->traverseNext(neighInfo);
	    neighElType = neighInfo->getType();
	  }

	  if (neighElType != 1)
	    oppVertex = (oppVertex == 0 ? 3 : 1);
	  else
	    oppVertex = (oppVertex == 0 ? 3 : 2);
	  break;
	case 5:
	  if (neighElType != 1) {
	    if (!reverseMode) {
	      neighInfo = stack->traverseNext(neighInfo);
	      neighElType = neighInfo->getType();
	    }
	  }
	  oppVertex = 3;
	  break;
	}

	neigh = 
	  dynamic_cast<Tetrahedron*>(const_cast<Element*>(neighInfo->getElement()));
      } else {
	// Neigh is compatible devisible. Put neigh to the list of patch elements 
	// and go to next neighbour.

	TEST_EXIT_DBG(*n_neigh < mesh->getMaxEdgeNeigh())
	  ("too many neighbours %d in refine patch\n", *n_neigh);
		
	refineList->setElement(*n_neigh, neigh);
	refineList->setElType(*n_neigh, neighElType);
	
	// We have to go back to the starting element via oppVertex values.

	refineList->setOppVertex(*n_neigh, 0, oppVertex); 
	
	(*n_neigh)++;

	int i = (oppVertex != 3 ? 3 : 2);

	if (neighInfo->getNeighbour(i)) {
	  oppVertex = neighInfo->getOppVertex(i);
	  int testIndex = neighInfo->getNeighbour(i)->getIndex();

	  neighInfo = stack->traverseNeighbour3d(neighInfo, i);

	  TEST_EXIT_DBG(neighInfo->getElement()->getIndex() == testIndex)
	    ("Should not happen!\n");

	  neighElType = neighInfo->getType();
	  neigh = 
	    dynamic_cast<Tetrahedron*>(const_cast<Element*>(neighInfo->getElement()));
	} else {
	  break;
	}
      }
    }
   
    if (neigh == el) {
      (*el_info) = neighInfo;

      return 0;
    }

   
    // The domain's boundary is reached. Loop back to the starting el.
    
    int i = *n_neigh - 1;
    oppVertex = refineList->getOppVertex(i, 0);
    do {
      TEST_EXIT_DBG(neighInfo->getNeighbour(oppVertex) && i > 0)
	("While looping back domains boundary was reached or i == 0\n");
      oppVertex = refineList->getOppVertex(i--, 0);

      int testIndex = neighInfo->getNeighbour(oppVertex)->getIndex();
      neighInfo = stack->traverseNeighbour3d(neighInfo, oppVertex);

      int edgeDof0, edgeDof1;
      for (edgeDof0 = 0; edgeDof0 < vertices; edgeDof0++)
	if (neigh->getDof(edgeDof0) == edge[0])
	  break;
      for (edgeDof1 = 0; edgeDof1 < vertices; edgeDof1++)
	if (neigh->getDof(edgeDof1) == edge[1])
	  break;

      TEST_EXIT_DBG(neighInfo->getElement()->getIndex() == testIndex)
	("Should not happen!\n");
    } while (neighInfo->getElement() != el);

    (*el_info) = neighInfo;
    
    return 1;
  }


  ElInfo* RefinementManager3d::refineFunction(ElInfo* el_info)
  {
    FUNCNAME("RefinementManager3d::refineFunction()");

    if (el_info->getElement()->getMark() <= 0)  
      return el_info;

    int bound = false;
    DegreeOfFreedom *edge[2];

    // === Get memory for a list of all elements at the refinement edge. ===

    RCNeighbourList *ref_list = new RCNeighbourList(mesh->getMaxEdgeNeigh());
    ref_list->setElType(0, el_info->getType());
    ref_list->setElement(0, el_info->getElement());
    int n_neigh = 1;

    if (el_info->getProjection(0) && 
	el_info->getProjection(0)->getType() == VOLUME_PROJECTION)
      newCoords = true;


    // === Give the refinement edge the right orientation. ===

    if (el_info->getElement()->getDof(0, 0) < el_info->getElement()->getDof(1, 0)) {
      edge[0] = const_cast<DegreeOfFreedom*>(el_info->getElement()->getDof(0));
      edge[1] = const_cast<DegreeOfFreedom*>(el_info->getElement()->getDof(1));
    } else {
      edge[1] = const_cast<DegreeOfFreedom*>(el_info->getElement()->getDof(0));
      edge[0] = const_cast<DegreeOfFreedom*>(el_info->getElement()->getDof(1));
    }


    // === Traverse and refine the refinement patch. ====

    if (getRefinePatch(&el_info, edge, 0, ref_list, &n_neigh)) {      
      // Domain's boundary was reached while looping around the refinement edge
      getRefinePatch(&el_info, edge, 1, ref_list, &n_neigh);
      bound = true;
    }

    // fill neighbour information inside the patch in the refinement list
    ref_list->getNeighOnPatch(n_neigh, bound);


    // ============ Check for periodic boundary ============

    DegreeOfFreedom *next_edge[2];
    DegreeOfFreedom *first_edge[2] = {edge[0], edge[1]};
    DegreeOfFreedom *last_edge[2] = {NULL, NULL};
    int n_neigh_periodic;

    DegreeOfFreedom newDOF = -1;
    DegreeOfFreedom lastNewDOF = -1;
    DegreeOfFreedom firstNewDOF = -1;

    RCNeighbourList *periodicList;
    std::map<int, VertexVector*>::iterator it;
    std::map<int, VertexVector*>::iterator end = mesh->getPeriodicAssociations().end();

    while (edge[0] != NULL) {
      periodicList = ref_list->periodicSplit(edge, 
					     next_edge,
					     &n_neigh,
					     &n_neigh_periodic);

      TEST_EXIT_DBG(periodicList)("periodicList = NULL\n");

      newDOF = refinePatch(edge, periodicList, n_neigh_periodic, bound);

      if (firstNewDOF == -1)
	firstNewDOF = newDOF;

      if (lastNewDOF != -1) {
	for (it = mesh->getPeriodicAssociations().begin(); it != end; ++it) {
	  if (it->second) {
	    if (((*(it->second))[edge[0][0]] == last_edge[0][0] &&
		 (*(it->second))[edge[1][0]] == last_edge[1][0]) || 
		((*(it->second))[edge[0][0]] == last_edge[1][0] &&
		 (*(it->second))[edge[1][0]] == last_edge[0][0])) {
	      (*(it->second))[lastNewDOF] = newDOF;
	      (*(it->second))[newDOF] = lastNewDOF;
	    } 
	  }
	}
      }
      lastNewDOF = newDOF;

      last_edge[0] = edge[0];
      last_edge[1] = edge[1];

      edge[0] = next_edge[0];
      edge[1] = next_edge[1];
    }

    if (lastNewDOF != firstNewDOF) {
      for (it = mesh->getPeriodicAssociations().begin(); it != end; ++it) {
	if (it->second) {
	  if (((*(it->second))[first_edge[0][0]] == last_edge[0][0] &&
	       (*(it->second))[first_edge[1][0]] == last_edge[1][0]) || 
	      ((*(it->second))[first_edge[0][0]] == last_edge[1][0] &&
	       (*(it->second))[first_edge[1][0]] == last_edge[0][0])) {	    
	    (*(it->second))[lastNewDOF] = firstNewDOF;
	    (*(it->second))[firstNewDOF] = lastNewDOF;
	  }
	}
      }
    }
  
    stack->update();

    delete ref_list;

    return el_info;
  }

}