A fix.

Geo/ChainComplex.cpp

@@ -894,6 +894,7 @@ void Chain::createPView(){
   int entityNum = *std::max_element(max,max+4) + 1;
   for(int i = 0; i < 4; i++) max[i] = _model->getMaxPhysicalNumber(i);
   int physicalNum = *std::max_element(max,max+4) + 1;
+  setNum(physicalNum);
   
   std::map<int, std::vector<MElement*> > entityMap;
   //int entityNum = _model->getMaxElementaryNumber(getDim())+1;
@@ -904,11 +905,13 @@ void Chain::createPView(){
   physicalInfo[physicalNum]=getName();
   physicalMap[entityNum] = physicalInfo;
   
-  _model->storeChain(getDim(), entityMap, physicalMap);
-  _model->setPhysicalName(getName(), getDim(), physicalNum);
-  
-  // only for visualization
-  if(!data.empty()) PView *chain = new PView(getName(), "ElementData", getGModel(), data, 0, 1);
+  if(!data.empty()){
+    _model->storeChain(getDim(), entityMap, physicalMap);
+    _model->setPhysicalName(getName(), getDim(), physicalNum);
+    
+    // only for visualization
+    PView *chain = new PView(getName(), "ElementData", getGModel(), data, 0, 1);
+  }
   
   return;
 }

Geo/ChainComplex.h

@@ -139,6 +139,8 @@ class Chain{
    std::map< Cell*, int, Less_Cell > _cells;
    // name of the chain (optional)
    std::string _name;
+   // physical group number of the chain
+   int _num;
    // cell complex this chain belongs to
    CellComplex* _cellComplex;
    GModel* _model;
@@ -261,7 +263,10 @@ class Chain{
    // get/set chain name
    std::string getName() { return _name; }
    void setName(std::string name) { _name=name; }
-
+   // get/set physical group number
+   int getNum() { return _num; }
+   void setNum(int num) { _num=num; }
+   
    // make local deformations to the chain to make it smoother and smaller
    // (for primary complex chains only, not for dual chains represented by primary cells (yet).)
    void smoothenChain();

Geo/Homology.h

@@ -46,6 +46,7 @@ class Homology
      for(int i = 0; i < 4; i++) {
        for(int j = 0; j < _generators[i].size(); j++){
          Chain* chain = _generators[i].at(j);
+         //_model->deletePhysicalGroup(chain->getDim(), chain->getNum());
          delete chain;
        }
      }