From ff35258615518d41d02c82e8d32569c1f0a9fdc9 Mon Sep 17 00:00:00 2001
From: ageay <ageay>
Date: Fri, 19 Jul 2013 15:32:47 +0000
Subject: [PATCH] On the highway to MEDReader : - umesh is no more used as base
 mesh to store chunks coming from MEDFile

It saves memory and allows to go to VTK data structure without overhead for MEDReader.
---
 src/MEDCoupling/MEDCoupling1GTUMesh.cxx  |  32 +-
 src/MEDCoupling/MEDCoupling1GTUMesh.hxx  |   3 +
 src/MEDCoupling/MEDCouplingUMesh.cxx     |   4 +-
 src/MEDCoupling_Swig/MEDCouplingCommon.i |   1 +
 src/MEDLoader/MEDFileMesh.cxx            |   6 +-
 src/MEDLoader/MEDFileMeshElt.cxx         | 119 +++---
 src/MEDLoader/MEDFileMeshElt.hxx         |  10 +-
 src/MEDLoader/MEDFileMeshLL.cxx          | 446 ++++++++++++++++++-----
 src/MEDLoader/MEDFileMeshLL.hxx          |  40 +-
 src/MEDLoader/Swig/MEDLoaderTest3.py     |   5 +
 10 files changed, 479 insertions(+), 187 deletions(-)

diff --git a/src/MEDCoupling/MEDCoupling1GTUMesh.cxx b/src/MEDCoupling/MEDCoupling1GTUMesh.cxx
index 8a8034b61..2fa8f049e 100644
--- a/src/MEDCoupling/MEDCoupling1GTUMesh.cxx
+++ b/src/MEDCoupling/MEDCoupling1GTUMesh.cxx
@@ -616,9 +616,8 @@ bool MEDCoupling1SGTUMesh::isEqualWithoutConsideringStr(const MEDCouplingMesh *o
   return true;
 }
 
-void MEDCoupling1SGTUMesh::checkCoherency() const throw(INTERP_KERNEL::Exception)
+void MEDCoupling1SGTUMesh::checkCoherencyOfConnectivity() const throw(INTERP_KERNEL::Exception)
 {
-  MEDCouplingPointSet::checkCoherency();
   const DataArrayInt *c1(_conn);
   if(c1)
     {
@@ -632,6 +631,12 @@ void MEDCoupling1SGTUMesh::checkCoherency() const throw(INTERP_KERNEL::Exception
     throw INTERP_KERNEL::Exception("Nodal connectivity array not defined !");
 }
 
+void MEDCoupling1SGTUMesh::checkCoherency() const throw(INTERP_KERNEL::Exception)
+{
+  MEDCouplingPointSet::checkCoherency();
+  checkCoherencyOfConnectivity();
+}
+
 void MEDCoupling1SGTUMesh::checkCoherency1(double eps) const throw(INTERP_KERNEL::Exception)
 {
   checkCoherency();
@@ -1649,14 +1654,8 @@ void MEDCoupling1DGTUMesh::checkFastEquivalWith(const MEDCouplingMesh *other, do
     }
 }
 
-/*!
- * If \a this pass this method, you are sure that connectivity arrays are not null, with exactly one component, no name, no component name, allocated.
- * In addition you are sure that the length of nodal connectivity index array is bigger than or equal to one.
- * In addition you are also sure that length of nodal connectivity is coherent with the content of the last value in the index array.
- */
-void MEDCoupling1DGTUMesh::checkCoherency() const throw(INTERP_KERNEL::Exception)
+void MEDCoupling1DGTUMesh::checkCoherencyOfConnectivity() const throw(INTERP_KERNEL::Exception)
 {
-  MEDCouplingPointSet::checkCoherency();
   const DataArrayInt *c1(_conn);
   if(c1)
     {
@@ -1702,11 +1701,22 @@ void MEDCoupling1DGTUMesh::checkCoherency() const throw(INTERP_KERNEL::Exception
   int szOfC1Exp=_conn_indx->back();
   if(sz2<szOfC1Exp)
     {
-      std::ostringstream oss; oss << "MEDCoupling1DGTUMesh::checkCoherency : The expected length of nodal connectivity array regarding index is " << szOfC1Exp << " but the actual size of it is " << c1->getNumberOfTuples() << " !";
+      std::ostringstream oss; oss << "MEDCoupling1DGTUMesh::checkCoherencyOfConnectivity : The expected length of nodal connectivity array regarding index is " << szOfC1Exp << " but the actual size of it is " << c1->getNumberOfTuples() << " !";
       throw INTERP_KERNEL::Exception(oss.str().c_str());
     }
 }
 
+/*!
+ * If \a this pass this method, you are sure that connectivity arrays are not null, with exactly one component, no name, no component name, allocated.
+ * In addition you are sure that the length of nodal connectivity index array is bigger than or equal to one.
+ * In addition you are also sure that length of nodal connectivity is coherent with the content of the last value in the index array.
+ */
+void MEDCoupling1DGTUMesh::checkCoherency() const throw(INTERP_KERNEL::Exception)
+{
+  MEDCouplingPointSet::checkCoherency();
+  checkCoherencyOfConnectivity();
+}
+
 void MEDCoupling1DGTUMesh::checkCoherency1(double eps) const throw(INTERP_KERNEL::Exception)
 {
   checkCoherency();
@@ -1735,7 +1745,7 @@ void MEDCoupling1DGTUMesh::checkCoherency2(double eps) const throw(INTERP_KERNEL
 
 int MEDCoupling1DGTUMesh::getNumberOfCells() const
 {
-  checkCoherency();//do not remove
+  checkCoherencyOfConnectivity();//do not remove
   return _conn_indx->getNumberOfTuples()-1;
 }
 
diff --git a/src/MEDCoupling/MEDCoupling1GTUMesh.hxx b/src/MEDCoupling/MEDCoupling1GTUMesh.hxx
index 748992d3f..723234f49 100644
--- a/src/MEDCoupling/MEDCoupling1GTUMesh.hxx
+++ b/src/MEDCoupling/MEDCoupling1GTUMesh.hxx
@@ -71,6 +71,7 @@ namespace ParaMEDMEM
     MEDCOUPLING_EXPORT virtual void allocateCells(int nbOfCells=0) throw(INTERP_KERNEL::Exception) = 0;
     MEDCOUPLING_EXPORT virtual void insertNextCell(const int *nodalConnOfCellBg, const int *nodalConnOfCellEnd) throw(INTERP_KERNEL::Exception) = 0;
     MEDCOUPLING_EXPORT virtual DataArrayInt *getNodalConnectivity() const throw(INTERP_KERNEL::Exception) = 0;
+    MEDCOUPLING_EXPORT virtual void checkCoherencyOfConnectivity() const throw(INTERP_KERNEL::Exception) = 0;
   protected:
     MEDCOUPLING_EXPORT MEDCoupling1GTUMesh(const char *name, const INTERP_KERNEL::CellModel& cm);
     MEDCOUPLING_EXPORT MEDCoupling1GTUMesh(const MEDCoupling1GTUMesh& other, bool recDeepCpy);
@@ -121,6 +122,7 @@ namespace ParaMEDMEM
     MEDCOUPLING_EXPORT void renumberNodesInConn(const int *newNodeNumbersO2N);
     MEDCOUPLING_EXPORT void fillCellIdsToKeepFromNodeIds(const int *begin, const int *end, bool fullyIn, DataArrayInt *&cellIdsKeptArr) const;
     // overload of MEDCoupling1GTUMesh
+    MEDCOUPLING_EXPORT void checkCoherencyOfConnectivity() const throw(INTERP_KERNEL::Exception);
     MEDCOUPLING_EXPORT void allocateCells(int nbOfCells=0) throw(INTERP_KERNEL::Exception);
     MEDCOUPLING_EXPORT void insertNextCell(const int *nodalConnOfCellBg, const int *nodalConnOfCellEnd) throw(INTERP_KERNEL::Exception);
   public://specific
@@ -188,6 +190,7 @@ namespace ParaMEDMEM
     MEDCOUPLING_EXPORT void renumberNodesInConn(const int *newNodeNumbersO2N);
     MEDCOUPLING_EXPORT void fillCellIdsToKeepFromNodeIds(const int *begin, const int *end, bool fullyIn, DataArrayInt *&cellIdsKeptArr) const;
     // overload of MEDCoupling1GTUMesh
+    MEDCOUPLING_EXPORT void checkCoherencyOfConnectivity() const throw(INTERP_KERNEL::Exception);
     MEDCOUPLING_EXPORT void allocateCells(int nbOfCells=0) throw(INTERP_KERNEL::Exception);
     MEDCOUPLING_EXPORT void insertNextCell(const int *nodalConnOfCellBg, const int *nodalConnOfCellEnd) throw(INTERP_KERNEL::Exception);
   public://specific
diff --git a/src/MEDCoupling/MEDCouplingUMesh.cxx b/src/MEDCoupling/MEDCouplingUMesh.cxx
index 01b9c156f..f90c9c49a 100644
--- a/src/MEDCoupling/MEDCouplingUMesh.cxx
+++ b/src/MEDCoupling/MEDCouplingUMesh.cxx
@@ -3129,7 +3129,7 @@ MEDCouplingPointSet *MEDCouplingUMesh::buildPartOfMySelfKeepCoords2(int start, i
  */
 MEDCouplingPointSet *MEDCouplingUMesh::buildPartOfMySelfKeepCoords(const int *begin, const int *end) const
 {
-  checkFullyDefined();
+  checkConnectivityFullyDefined();
   int ncell=getNumberOfCells();
   MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> ret=MEDCouplingUMesh::New();
   ret->_mesh_dim=_mesh_dim;
@@ -6671,7 +6671,7 @@ DataArrayInt *MEDCouplingUMesh::rearrange2ConsecutiveCellTypes()
  */
 std::vector<MEDCouplingUMesh *> MEDCouplingUMesh::splitByType() const
 {
-  checkFullyDefined();
+  checkConnectivityFullyDefined();
   const int *conn=_nodal_connec->getConstPointer();
   const int *connI=_nodal_connec_index->getConstPointer();
   int nbOfCells=getNumberOfCells();
diff --git a/src/MEDCoupling_Swig/MEDCouplingCommon.i b/src/MEDCoupling_Swig/MEDCouplingCommon.i
index dd1ae5fbc..dad36a1bb 100644
--- a/src/MEDCoupling_Swig/MEDCouplingCommon.i
+++ b/src/MEDCoupling_Swig/MEDCouplingCommon.i
@@ -2765,6 +2765,7 @@ namespace ParaMEDMEM
     INTERP_KERNEL::NormalizedCellType getCellModelEnum() const throw(INTERP_KERNEL::Exception);
     int getNodalConnectivityLength() const throw(INTERP_KERNEL::Exception);
     virtual void allocateCells(int nbOfCells=0) throw(INTERP_KERNEL::Exception);
+    virtual void checkCoherencyOfConnectivity() const throw(INTERP_KERNEL::Exception);
     %extend
     {
       virtual void insertNextCell(PyObject *li) throw(INTERP_KERNEL::Exception)
diff --git a/src/MEDLoader/MEDFileMesh.cxx b/src/MEDLoader/MEDFileMesh.cxx
index 638681ece..986265c53 100644
--- a/src/MEDLoader/MEDFileMesh.cxx
+++ b/src/MEDLoader/MEDFileMesh.cxx
@@ -1962,7 +1962,7 @@ MEDFileMesh *MEDFileUMesh::deepCpy() const throw(INTERP_KERNEL::Exception)
   for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDFileUMeshSplitL1> >::const_iterator it=_ms.begin();it!=_ms.end();it++,i++)
     {
       if((const MEDFileUMeshSplitL1 *)(*it))
-        ret->_ms[i]=(*it)->deepCpy();
+        ret->_ms[i]=(*it)->deepCpy(ret->_coords);
     }
   return ret.retn();
 }
@@ -2983,7 +2983,6 @@ void MEDFileUMesh::checkMeshDimCoherency(int meshDim, int meshDimRelToMax) const
  *  \param [in] coords - the new node coordinates array.
  *  \throw If \a coords == \c NULL.
  */
-
 void MEDFileUMesh::setCoords(DataArrayDouble *coords) throw(INTERP_KERNEL::Exception)
 {
   if(!coords)
@@ -2995,6 +2994,9 @@ void MEDFileUMesh::setCoords(DataArrayDouble *coords) throw(INTERP_KERNEL::Excep
   _fam_coords=DataArrayInt::New();
   _fam_coords->alloc(nbOfTuples,1);
   _fam_coords->fillWithZero();
+  for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDFileUMeshSplitL1> >::iterator it=_ms.begin();it!=_ms.end();it++)
+    if((MEDFileUMeshSplitL1 *)(*it))
+      (*it)->setCoords(coords);
 }
 
 /*!
diff --git a/src/MEDLoader/MEDFileMeshElt.cxx b/src/MEDLoader/MEDFileMeshElt.cxx
index 6321d76bc..0725d6890 100644
--- a/src/MEDLoader/MEDFileMeshElt.cxx
+++ b/src/MEDLoader/MEDFileMeshElt.cxx
@@ -62,17 +62,17 @@ bool MEDFileUMeshPerType::isExisting(med_idt fid, const char *mName, int dt, int
 
 int MEDFileUMeshPerType::getDim() const
 {
-  const INTERP_KERNEL::CellModel& cm=INTERP_KERNEL::CellModel::GetCellModel(_type);
-  return cm.getDimension();
+  return _m->getMeshDimension();
 }
 
 MEDFileUMeshPerType::MEDFileUMeshPerType(med_idt fid, const char *mName, int dt, int it, int mdim, med_geometry_type geoElt, INTERP_KERNEL::NormalizedCellType type,
-                                         med_entity_type entity, MEDFileMeshReadSelector *mrs):_type(type),_entity(entity)
+                                         med_entity_type entity, MEDFileMeshReadSelector *mrs):_entity(entity)
 {
   med_bool changement,transformation;
   int curNbOfElem=MEDmeshnEntity(fid,mName,dt,it,entity,geoElt,MED_CONNECTIVITY,MED_NODAL,
                                  &changement,&transformation);
-  if(type!=INTERP_KERNEL::NORM_POLYGON && type!=INTERP_KERNEL::NORM_POLYHED)
+  const INTERP_KERNEL::CellModel& cm=INTERP_KERNEL::CellModel::GetCellModel(type);
+  if(!cm.isDynamic())
     {
       loadFromStaticType(fid,mName,dt,it,mdim,curNbOfElem,geoElt,type,entity,mrs);
       return;
@@ -89,24 +89,15 @@ MEDFileUMeshPerType::MEDFileUMeshPerType(med_idt fid, const char *mName, int dt,
 void MEDFileUMeshPerType::loadFromStaticType(med_idt fid, const char *mName, int dt, int it, int mdim, int curNbOfElem, med_geometry_type geoElt, INTERP_KERNEL::NormalizedCellType type,
                                              med_entity_type entity, MEDFileMeshReadSelector *mrs)
 {
-  _conn=DataArrayInt::New();
-  int nbOfNodesPerCell=(geoElt%100);
-  _conn->alloc((nbOfNodesPerCell+1)*curNbOfElem,1);
-  _conn_index=DataArrayInt::New();
-  _conn_index->alloc(curNbOfElem+1,1);
-  INTERP_KERNEL::AutoPtr<int> connTab=new int[(nbOfNodesPerCell)*curNbOfElem];
-  MEDmeshElementConnectivityRd(fid,mName,dt,it,entity,geoElt,MED_NODAL,MED_FULL_INTERLACE,connTab);
+  _m=MEDCoupling1SGTUMesh::New(mName,type);
+  MEDCoupling1SGTUMesh *mc(dynamic_cast<MEDCoupling1SGTUMesh *>((MEDCoupling1GTUMesh *)_m));
+  MEDCouplingAutoRefCountObjectPtr<DataArrayInt> conn(DataArrayInt::New());
+  int nbOfNodesPerCell=mc->getNumberOfNodesPerCell();
+  conn->alloc(nbOfNodesPerCell*curNbOfElem,1);
+  MEDmeshElementConnectivityRd(fid,mName,dt,it,entity,geoElt,MED_NODAL,MED_FULL_INTERLACE,conn->getPointer());
+  std::transform(conn->begin(),conn->end(),conn->getPointer(),std::bind2nd(std::plus<int>(),-1));
+  mc->setNodalConnectivity(conn);
   loadCommonPart(fid,mName,dt,it,mdim,curNbOfElem,geoElt,entity,mrs);
-  int *w1=_conn->getPointer();
-  int *w2=_conn_index->getPointer();
-  *w2++=0;
-  const int *wi=connTab;
-  for(int i=0;i<curNbOfElem;i++,wi+=nbOfNodesPerCell,w2++)
-    {
-      *w1++=(int)type;
-      w1=std::transform(wi,wi+nbOfNodesPerCell,w1,std::bind2nd(std::plus<int>(),-1));
-      *w2=w2[-1]+nbOfNodesPerCell+1;
-    }
 }
 
 void MEDFileUMeshPerType::loadCommonPart(med_idt fid, const char *mName, int dt, int it, int mdim, int curNbOfElem, med_geometry_type geoElt,
@@ -155,24 +146,14 @@ void MEDFileUMeshPerType::loadPolyg(med_idt fid, const char *mName, int dt, int
 {
   med_bool changement,transformation;
   med_int curNbOfElem=MEDmeshnEntity(fid,mName,dt,it,entity,MED_POLYGON,MED_INDEX_NODE,MED_NODAL,&changement,&transformation)-1;
-  _conn_index=DataArrayInt::New();
-  _conn_index->alloc(curNbOfElem+1,1);
-  _conn=DataArrayInt::New();
-  _conn->alloc(arraySize+curNbOfElem,1);
-  INTERP_KERNEL::AutoPtr<int> locConn=new int[arraySize];
-  MEDmeshPolygonRd(fid,mName,dt,it,MED_CELL,MED_NODAL,_conn_index->getPointer(),locConn);
-  int *w1=_conn->getPointer();
-  int *w2=_conn_index->getPointer();
-  const int *wi=locConn;
-  for(int i=0;i<curNbOfElem;i++,w2++)
-    {
-      *w1++=(int)INTERP_KERNEL::NORM_POLYGON;
-      const int *wi2=wi+(w2[1]-w2[0]);
-      w1=std::transform(wi,wi2,w1,std::bind2nd(std::plus<int>(),-1));
-      wi=wi2;
-      *w2=*w2-1+i;
-    }
-  *w2=*w2-1+curNbOfElem;
+  _m=MEDCoupling1DGTUMesh::New(mName,INTERP_KERNEL::NORM_POLYGON);
+  MEDCoupling1DGTUMesh *mc(dynamic_cast<MEDCoupling1DGTUMesh *>((MEDCoupling1GTUMesh *)_m));
+  MEDCouplingAutoRefCountObjectPtr<DataArrayInt> conn(DataArrayInt::New()),connI(DataArrayInt::New());
+  conn->alloc(arraySize,1); connI->alloc(curNbOfElem+1,1);
+  MEDmeshPolygonRd(fid,mName,dt,it,MED_CELL,MED_NODAL,connI->getPointer(),conn->getPointer());
+  std::transform(conn->begin(),conn->end(),conn->getPointer(),std::bind2nd(std::plus<int>(),-1));
+  std::transform(connI->begin(),connI->end(),connI->getPointer(),std::bind2nd(std::plus<int>(),-1));
+  mc->setNodalConnectivity(conn,connI);
   loadCommonPart(fid,mName,dt,it,mdim,curNbOfElem,MED_POLYGON,entity,mrs);
 }
 
@@ -182,24 +163,25 @@ void MEDFileUMeshPerType::loadPolyh(med_idt fid, const char *mName, int dt, int
   med_bool changement,transformation;
   med_int indexFaceLgth=MEDmeshnEntity(fid,mName,dt,it,MED_CELL,MED_POLYHEDRON,MED_INDEX_NODE,MED_NODAL,&changement,&transformation);
   int curNbOfElem=MEDmeshnEntity(fid,mName,dt,it,MED_CELL,MED_POLYHEDRON,MED_INDEX_FACE,MED_NODAL,&changement,&transformation)-1;
+  _m=MEDCoupling1DGTUMesh::New(mName,INTERP_KERNEL::NORM_POLYHED);
+  MEDCoupling1DGTUMesh *mc(dynamic_cast<MEDCoupling1DGTUMesh *>((MEDCoupling1GTUMesh *)_m));
   INTERP_KERNEL::AutoPtr<int> index=new int[curNbOfElem+1];
   INTERP_KERNEL::AutoPtr<int> indexFace=new int[indexFaceLgth];
   INTERP_KERNEL::AutoPtr<int> locConn=new int[connFaceLgth];
   MEDmeshPolyhedronRd(fid,mName,dt,it,MED_CELL,MED_NODAL,index,indexFace,locConn);
+  MEDCouplingAutoRefCountObjectPtr<DataArrayInt> conn(DataArrayInt::New()),connI(DataArrayInt::New());
   int arraySize=connFaceLgth;
   for(int i=0;i<curNbOfElem;i++)
     arraySize+=index[i+1]-index[i]-1;
-  _conn=DataArrayInt::New();
-  _conn->alloc(arraySize+curNbOfElem,1);
-  int *wFinalConn=_conn->getPointer();
-  _conn_index=DataArrayInt::New();
-  _conn_index->alloc(curNbOfElem+1,1);
-  int *finalIndex=_conn_index->getPointer();
+  conn=DataArrayInt::New();
+  conn->alloc(arraySize,1);
+  int *wFinalConn=conn->getPointer();
+  connI->alloc(curNbOfElem+1,1);
+  int *finalIndex(connI->getPointer());
   finalIndex[0]=0;
   for(int i=0;i<curNbOfElem;i++)
     {
-      *wFinalConn++=(int)INTERP_KERNEL::NORM_POLYHED;
-      finalIndex[i+1]=finalIndex[i]+index[i+1]-index[i]-1+indexFace[index[i+1]-1]-indexFace[index[i]-1]+1;
+      finalIndex[i+1]=finalIndex[i]+index[i+1]-index[i]-1+indexFace[index[i+1]-1]-indexFace[index[i]-1];
       wFinalConn=std::transform(locConn+indexFace[index[i]-1]-1,locConn+indexFace[index[i]]-1,wFinalConn,std::bind2nd(std::plus<int>(),-1));
       for(int j=index[i];j<index[i+1]-1;j++)
         {
@@ -207,10 +189,11 @@ void MEDFileUMeshPerType::loadPolyh(med_idt fid, const char *mName, int dt, int
           wFinalConn=std::transform(locConn+indexFace[j]-1,locConn+indexFace[j+1]-1,wFinalConn,std::bind2nd(std::plus<int>(),-1));
         }
     }
+  mc->setNodalConnectivity(conn,connI);
   loadCommonPart(fid,mName,dt,it,mdim,curNbOfElem,MED_POLYHEDRON,entity,mrs);
 }
 
-void MEDFileUMeshPerType::write(med_idt fid, const char *mname, int mdim, const MEDCouplingUMesh *m, const DataArrayInt *fam, const DataArrayInt *num, const DataArrayAsciiChar *names)
+void MEDFileUMeshPerType::Write(med_idt fid, const char *mname, int mdim, const MEDCoupling1GTUMesh *m, const DataArrayInt *fam, const DataArrayInt *num, const DataArrayAsciiChar *names)
 {
   int nbOfCells=m->getNumberOfCells();
   if(nbOfCells<1)
@@ -220,46 +203,42 @@ void MEDFileUMeshPerType::write(med_idt fid, const char *mname, int mdim, const
   INTERP_KERNEL::NormalizedCellType ikt=m->getTypeOfCell(0);
   const INTERP_KERNEL::CellModel& cm=INTERP_KERNEL::CellModel::GetCellModel(ikt);
   med_geometry_type curMedType=typmai3[(int)ikt];
-  const int *conn=m->getNodalConnectivity()->getConstPointer();
-  const int *connI=m->getNodalConnectivityIndex()->getConstPointer();
-  if(ikt!=INTERP_KERNEL::NORM_POLYGON && ikt!=INTERP_KERNEL::NORM_POLYHED)
+  if(!cm.isDynamic())
     {
-      int nbNodesPerCell=cm.getNumberOfNodes();
-      INTERP_KERNEL::AutoPtr<int> tab=new int[nbNodesPerCell*nbOfCells];
-      int *w=tab;
-      for(int i=0;i<nbOfCells;i++)
-        w=std::transform(conn+connI[i]+1,conn+connI[i+1],w,std::bind2nd(std::plus<int>(),1));
-      MEDmeshElementConnectivityWr(fid,mname,dt,it,timm,MED_CELL,curMedType,MED_NODAL,MED_FULL_INTERLACE,nbOfCells,tab);
+      const MEDCoupling1SGTUMesh *m0(dynamic_cast<const MEDCoupling1SGTUMesh *>(m));
+      if(!m0)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshPerType::Write : internal error #1 !");
+      MEDCouplingAutoRefCountObjectPtr<DataArrayInt> arr(m0->getNodalConnectivity()->deepCpy());
+      std::transform(arr->begin(),arr->end(),arr->getPointer(),std::bind2nd(std::plus<int>(),1));
+      MEDmeshElementConnectivityWr(fid,mname,dt,it,timm,MED_CELL,curMedType,MED_NODAL,MED_FULL_INTERLACE,nbOfCells,arr->begin());
     }
   else
     {
+      const MEDCoupling1DGTUMesh *m0(dynamic_cast<const MEDCoupling1DGTUMesh *>(m));
+      if(!m0)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshPerType::Write : internal error #2 !");
       if(ikt==INTERP_KERNEL::NORM_POLYGON)
         {
-          INTERP_KERNEL::AutoPtr<int> tab1=new int[nbOfCells+1];
-          INTERP_KERNEL::AutoPtr<int> tab2=new int[m->getMeshLength()];
-          int *wI=tab1; *wI=1;
-          int *w=tab2;
-          for(int i=0;i<nbOfCells;i++,wI++)
-            {
-              wI[1]=wI[0]+connI[i+1]-connI[i]-1;
-              w=std::transform(conn+connI[i]+1,conn+connI[i+1],w,std::bind2nd(std::plus<int>(),1));
-            }
-          MEDmeshPolygonWr(fid,mname,dt,it,timm,MED_CELL,MED_NODAL,nbOfCells+1,tab1,tab2);
+          MEDCouplingAutoRefCountObjectPtr<DataArrayInt> arr(m0->getNodalConnectivity()->deepCpy()),arrI(m0->getNodalConnectivityIndex()->deepCpy());
+          std::transform(arr->begin(),arr->end(),arr->getPointer(),std::bind2nd(std::plus<int>(),1));
+          std::transform(arrI->begin(),arrI->end(),arrI->getPointer(),std::bind2nd(std::plus<int>(),1));
+          MEDmeshPolygonWr(fid,mname,dt,it,timm,MED_CELL,MED_NODAL,nbOfCells+1,arrI->begin(),arr->begin());
         }
       else
         {
-          int meshLgth=m->getMeshLength();
+          const int *conn(m0->getNodalConnectivity()->begin()),*connI(m0->getNodalConnectivityIndex()->begin());
+          int meshLgth=m0->getNodalConnectivityLength();
           int nbOfFaces=std::count(conn,conn+meshLgth,-1)+nbOfCells;
           INTERP_KERNEL::AutoPtr<int> tab1=new int[nbOfCells+1];
           int *w1=tab1; *w1=1;
           INTERP_KERNEL::AutoPtr<int> tab2=new int[nbOfFaces+1];
           int *w2=tab2; *w2=1;
-          INTERP_KERNEL::AutoPtr<int> bigtab=new int[meshLgth-nbOfCells];
+          INTERP_KERNEL::AutoPtr<int> bigtab=new int[meshLgth];
           int *bt=bigtab;
           for(int i=0;i<nbOfCells;i++,w1++)
             {
               int nbOfFaces2=0;
-              for(const int *w=conn+connI[i]+1;w!=conn+connI[i+1];w2++)
+              for(const int *w=conn+connI[i];w!=conn+connI[i+1];w2++)
                 {
                   const int *wend=std::find(w,conn+connI[i+1],-1);
                   bt=std::transform(w,wend,bt,std::bind2nd(std::plus<int>(),1));
diff --git a/src/MEDLoader/MEDFileMeshElt.hxx b/src/MEDLoader/MEDFileMeshElt.hxx
index f870ef208..af728268a 100644
--- a/src/MEDLoader/MEDFileMeshElt.hxx
+++ b/src/MEDLoader/MEDFileMeshElt.hxx
@@ -22,6 +22,7 @@
 #define __MEDFILEMESHELT_HXX__
 
 #include "MEDCouplingMemArray.hxx"
+#include "MEDCoupling1GTUMesh.hxx"
 #include "MEDCouplingAutoRefCountObjectPtr.hxx"
 
 #include "NormalizedUnstructuredMesh.hxx"
@@ -40,12 +41,11 @@ namespace ParaMEDMEM
     static bool isExisting(med_idt fid, const char *mName, int dt, int it, med_geometry_type geoElt, med_entity_type& whichEntity);
     std::size_t getHeapMemorySize() const { return 0; }
     int getDim() const;
-    const DataArrayInt *getNodal() const { return _conn; }
-    const DataArrayInt *getNodalIndex() const { return _conn_index; }
+    MEDCoupling1GTUMesh *getMesh() const { return const_cast<MEDCoupling1GTUMesh *>((const MEDCoupling1GTUMesh *)_m); }
     const DataArrayInt *getFam() const { return _fam; }
     const DataArrayInt *getNum() const { return _num; }
     const DataArrayAsciiChar *getNames() const { return _names; }
-    static void write(med_idt fid, const char *mname, int mdim, const MEDCouplingUMesh *m, const DataArrayInt *fam, const DataArrayInt *num, const DataArrayAsciiChar *names);
+    static void Write(med_idt fid, const char *mname, int mdim, const MEDCoupling1GTUMesh *m, const DataArrayInt *fam, const DataArrayInt *num, const DataArrayAsciiChar *names);
   private:
     MEDFileUMeshPerType(med_idt fid, const char *mName, int dt, int it, int mdim, med_geometry_type geoElt, INTERP_KERNEL::NormalizedCellType type,
                         med_entity_type entity, MEDFileMeshReadSelector *mrs);
@@ -57,12 +57,10 @@ namespace ParaMEDMEM
                    med_entity_type entity, MEDFileMeshReadSelector *mrs);
     void loadCommonPart(med_idt fid, const char *mName, int dt, int it, int mdim, int curNbOfElem, med_geometry_type geoElt, med_entity_type entity, MEDFileMeshReadSelector *mrs);
   private:
-    MEDCouplingAutoRefCountObjectPtr<DataArrayInt> _conn;
-    MEDCouplingAutoRefCountObjectPtr<DataArrayInt> _conn_index;
+    MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> _m;
     MEDCouplingAutoRefCountObjectPtr<DataArrayInt> _num;
     MEDCouplingAutoRefCountObjectPtr<DataArrayInt> _fam;
     MEDCouplingAutoRefCountObjectPtr<DataArrayAsciiChar> _names;
-    INTERP_KERNEL::NormalizedCellType _type;
     med_entity_type _entity;
   };
 }
diff --git a/src/MEDLoader/MEDFileMeshLL.cxx b/src/MEDLoader/MEDFileMeshLL.cxx
index 5ff4d8669..ea4206e0d 100644
--- a/src/MEDLoader/MEDFileMeshLL.cxx
+++ b/src/MEDLoader/MEDFileMeshLL.cxx
@@ -467,23 +467,22 @@ MEDFileUMeshPermCompute::MEDFileUMeshPermCompute(const MEDFileUMeshSplitL1* st):
  */
 MEDFileUMeshPermCompute::operator MEDCouplingUMesh *() const
 {
-  _st->_m_by_types->updateTime();
   _st->_num->updateTime();
   if((MEDCouplingUMesh *)_m==0)
     {
       updateTime();
-      _m=static_cast<MEDCouplingUMesh *>(_st->_m_by_types->deepCpy());
+      _m=static_cast<MEDCouplingUMesh *>(_st->_m_by_types.getUmesh()->deepCpy());
       _m->renumberCells(_st->_num->getConstPointer(),true);
       return _m.retn();
     }
   else
     {
-      if(_mpt_time==_st->_m_by_types->getTimeOfThis() && _num_time==_st->_num->getTimeOfThis())
+      if(_mpt_time==_st->_m_by_types.getTimeOfThis() && _num_time==_st->_num->getTimeOfThis())
         return _m.retn();
       else
         {
           updateTime();
-          _m=static_cast<MEDCouplingUMesh *>(_st->_m_by_types->deepCpy());
+          _m=static_cast<MEDCouplingUMesh *>(_st->_m_by_types.getUmesh()->deepCpy());
           _m->renumberCells(_st->_num->getConstPointer(),true);
           return _m.retn();
         }
@@ -497,7 +496,7 @@ void MEDFileUMeshPermCompute::operator=(MEDCouplingUMesh *m)
 
 void MEDFileUMeshPermCompute::updateTime() const
 {
-  _mpt_time=_st->_m_by_types->getTimeOfThis();
+  _mpt_time=_st->_m_by_types.getTimeOfThis();
   _num_time=_st->_num->getTimeOfThis();
 }
 
@@ -511,45 +510,35 @@ MEDFileUMeshSplitL1::MEDFileUMeshSplitL1(const MEDFileUMeshL2& l2, const char *m
   if(v.empty())
     return;
   int sz=v.size();
-  std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> > msMSafe(sz);
-  std::vector<const MEDCouplingUMesh *> ms(sz);
+  std::vector<const MEDCoupling1GTUMesh *> ms(sz);
+  std::vector<const DataArrayInt *> fams(sz),nums(sz);
+  std::vector<const DataArrayChar *> names(sz); 
   for(int i=0;i<sz;i++)
     {
-      MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> tmp=MEDCouplingUMesh::New("",v[i]->getDim());
+      MEDCoupling1GTUMesh *elt(v[i]->getMesh());
       MEDCouplingAutoRefCountObjectPtr<DataArrayDouble> tmp2=l2.getCoords();
-      tmp->setCoords(tmp2);
-      tmp->setConnectivity(const_cast<DataArrayInt *>(v[i]->getNodal()),const_cast<DataArrayInt *>(v[i]->getNodalIndex()));
-      ms[i]=tmp; msMSafe[i]=tmp;
+      elt->setCoords(tmp2);
+      ms[i]=elt;
     }
-  _m_by_types=MEDCouplingUMesh::MergeUMeshesOnSameCoords(ms);
-  _m_by_types->setName(mName);
+  _m_by_types.assignParts(ms);
   if(l2.isFamDefinedOnLev(id))
     {
-      int nbOfCells=_m_by_types->getNumberOfCells();
-      _fam=DataArrayInt::New();
-      _fam->alloc(nbOfCells,1);
-      int *w=_fam->getPointer();
       for(int i=0;i<sz;i++)
-        w=std::copy(v[i]->getFam()->getConstPointer(),v[i]->getFam()->getConstPointer()+v[i]->getFam()->getNumberOfTuples(),w);
+        fams[i]=v[i]->getFam();
+      _fam=DataArrayInt::Aggregate(fams);
     }
   if(l2.isNumDefinedOnLev(id))
     {
-      int nbOfCells=_m_by_types->getNumberOfCells();
-      _num=DataArrayInt::New();
-      _num->alloc(nbOfCells,1);
-      int *w=_num->getPointer();
       for(int i=0;i<sz;i++)
-        w=std::copy(v[i]->getNum()->getConstPointer(),v[i]->getNum()->getConstPointer()+v[i]->getNum()->getNumberOfTuples(),w);
+        nums[i]=v[i]->getNum();
+      _num=DataArrayInt::Aggregate(nums);
       computeRevNum();
     }
   if(l2.isNamesDefinedOnLev(id))
     {
-      int nbOfCells=_m_by_types->getNumberOfCells();
-      _names=DataArrayAsciiChar::New();
-      _names->alloc(nbOfCells,MED_SNAME_SIZE);
-      char *w=_names->getPointer();
       for(int i=0;i<sz;i++)
-        w=std::copy(v[i]->getNames()->getConstPointer(),v[i]->getNames()->getConstPointer()+v[i]->getNames()->getNbOfElems(),w);
+        names[i]=v[i]->getNames();
+      _names=dynamic_cast<DataArrayAsciiChar *>(DataArrayChar::Aggregate(names));
     }
 }
 
@@ -566,12 +555,7 @@ MEDFileUMeshSplitL1::MEDFileUMeshSplitL1(MEDCouplingUMesh *m, bool newOrOld):_m(
 std::size_t MEDFileUMeshSplitL1::getHeapMemorySize() const
 {
   std::size_t ret=0;
-  if((const MEDCouplingUMesh *)_m_by_types)
-    {
-      ret+=_m_by_types->getHeapMemorySize();
-      if((const DataArrayDouble *)_m_by_types->getCoords())
-        ret-=_m_by_types->getCoords()->getHeapMemorySize();
-    }
+  ret+=_m_by_types.getHeapMemorySize();
   if((const DataArrayInt*)_fam)
     ret+=_fam->getHeapMemorySize();
   if((const DataArrayInt*)_num)
@@ -583,11 +567,10 @@ std::size_t MEDFileUMeshSplitL1::getHeapMemorySize() const
   return ret;
 }
 
-MEDFileUMeshSplitL1 *MEDFileUMeshSplitL1::deepCpy() const
+MEDFileUMeshSplitL1 *MEDFileUMeshSplitL1::deepCpy(DataArrayDouble *coords) const
 {
   MEDCouplingAutoRefCountObjectPtr<MEDFileUMeshSplitL1> ret=new MEDFileUMeshSplitL1(*this);
-  if((const MEDCouplingUMesh*)_m_by_types)
-    ret->_m_by_types=static_cast<MEDCouplingUMesh*>(_m_by_types->deepCpy());
+  ret->_m_by_types=_m_by_types.deepCpy(coords);
   if((const DataArrayInt *)_fam)
     ret->_fam=_fam->deepCpy();
   if((const DataArrayInt *)_num)
@@ -601,19 +584,8 @@ MEDFileUMeshSplitL1 *MEDFileUMeshSplitL1::deepCpy() const
 
 bool MEDFileUMeshSplitL1::isEqual(const MEDFileUMeshSplitL1 *other, double eps, std::string& what) const
 {
-  const MEDCouplingUMesh *m1=_m_by_types;
-  const MEDCouplingUMesh *m2=other->_m_by_types;
-  if((m1==0 && m2!=0) || (m1!=0 && m2==0))
-    {
-      what="Presence of mesh in one sublevel and not in other!";
-      return false;
-    }
-  if(m1)
-    if(!m1->isEqual(m2,eps))
-      {
-        what="meshes at a sublevel are not deeply equal !";
-        return false;
-      }
+  if(!_m_by_types.isEqual(other->_m_by_types,eps,what))
+    return false;
   const DataArrayInt *d1=_fam;
   const DataArrayInt *d2=other->_fam;
   if((d1==0 && d2!=0) || (d1!=0 && d2==0))
@@ -658,18 +630,12 @@ bool MEDFileUMeshSplitL1::isEqual(const MEDFileUMeshSplitL1 *other, double eps,
 
 void MEDFileUMeshSplitL1::synchronizeTinyInfo(const MEDFileMesh& master) const
 {
-  const MEDCouplingUMesh *tmp=_m_by_types;
-  if(!tmp)
-    return ;
-  (const_cast<MEDCouplingUMesh *>(tmp))->setName(master.getName());
-  (const_cast<MEDCouplingUMesh *>(tmp))->setDescription(master.getDescription());
-  (const_cast<MEDCouplingUMesh *>(tmp))->setTime(master.getTimeValue(),master.getIteration(),master.getOrder());
-  (const_cast<MEDCouplingUMesh *>(tmp))->setTimeUnit(master.getTimeUnit());
+  _m_by_types.synchronizeTinyInfo(master);
 }
 
 void MEDFileUMeshSplitL1::clearNonDiscrAttributes() const
 {
-  ClearNonDiscrAttributes(_m_by_types);
+  _m_by_types.clearNonDiscrAttributes();
 }
 
 void MEDFileUMeshSplitL1::ClearNonDiscrAttributes(const MEDCouplingMesh *tmp)
@@ -682,20 +648,25 @@ void MEDFileUMeshSplitL1::ClearNonDiscrAttributes(const MEDCouplingMesh *tmp)
   (const_cast<MEDCouplingMesh *>(tmp))->setTimeUnit("");
 }
 
+void MEDFileUMeshSplitL1::setCoords(DataArrayDouble *coords) throw(INTERP_KERNEL::Exception)
+{
+  _m_by_types.setCoords(coords);
+}
+
 void MEDFileUMeshSplitL1::assignMesh(MEDCouplingUMesh *m, bool newOrOld) throw(INTERP_KERNEL::Exception)
 {
   if(newOrOld)
     {
       m->incrRef();
       _m=m;
-      _m_by_types=(MEDCouplingUMesh *)m->deepCpy();
-      MEDCouplingAutoRefCountObjectPtr<DataArrayInt> da=_m_by_types->getRenumArrForConsecutiveCellTypesSpec(typmai2,typmai2+MED_N_CELL_FIXED_GEO);
+      _m_by_types.assignUMesh(dynamic_cast<MEDCouplingUMesh *>(m->deepCpy()));
+      MEDCouplingAutoRefCountObjectPtr<DataArrayInt> da=_m_by_types.getUmesh()->getRenumArrForConsecutiveCellTypesSpec(typmai2,typmai2+MED_N_CELL_FIXED_GEO);
       if(!da->isIdentity())
         {
           _num=da->invertArrayO2N2N2O(m->getNumberOfCells());
           _m.updateTime();
           computeRevNum();
-          _m_by_types->renumberCells(da->getConstPointer(),false);
+          _m_by_types.getUmesh()->renumberCells(da->getConstPointer(),false);
         }
     }
   else
@@ -703,7 +674,7 @@ void MEDFileUMeshSplitL1::assignMesh(MEDCouplingUMesh *m, bool newOrOld) throw(I
       if(!m->checkConsecutiveCellTypesAndOrder(typmai2,typmai2+MED_N_CELL_FIXED_GEO))
         throw INTERP_KERNEL::Exception("MEDFileUMeshSplitL1::assignMesh : the mode of mesh setting expects to follow the MED file numbering convention ! it is not the case !");
       m->incrRef();
-      _m_by_types=m;
+      _m_by_types.assignUMesh(m);
     }
   _fam=DataArrayInt::New();
   _fam->alloc(m->getNumberOfCells(),1);
@@ -712,7 +683,7 @@ void MEDFileUMeshSplitL1::assignMesh(MEDCouplingUMesh *m, bool newOrOld) throw(I
 
 bool MEDFileUMeshSplitL1::empty() const
 {
-  return ((const MEDCouplingUMesh *)_m_by_types)==0;
+  return _m_by_types.empty();
 }
 
 bool MEDFileUMeshSplitL1::presenceOfOneFams(const std::vector<int>& ids) const
@@ -725,12 +696,12 @@ bool MEDFileUMeshSplitL1::presenceOfOneFams(const std::vector<int>& ids) const
 
 int MEDFileUMeshSplitL1::getMeshDimension() const
 {
-  return _m_by_types->getMeshDimension();
+  return _m_by_types.getMeshDimension();
 }
 
 void MEDFileUMeshSplitL1::simpleRepr(std::ostream& oss) const
 {
-  std::vector<int> code=_m_by_types->getDistributionOfTypes();
+  std::vector<int> code=_m_by_types.getDistributionOfTypes();
   int nbOfTypes=code.size()/3;
   for(int i=0;i<nbOfTypes;i++)
     {
@@ -741,15 +712,13 @@ void MEDFileUMeshSplitL1::simpleRepr(std::ostream& oss) const
 
 int MEDFileUMeshSplitL1::getSize() const throw(INTERP_KERNEL::Exception)
 {
-  if((const MEDCouplingUMesh *)_m_by_types==0)
-    throw INTERP_KERNEL::Exception("MEDFileUMeshSplitL1::getSize : no mesh specified at level !");
-  return _m_by_types->getNumberOfCells();
+  return _m_by_types.getSize();
 }
 
 MEDCouplingUMesh *MEDFileUMeshSplitL1::getFamilyPart(const int *idsBg, const int *idsEnd, bool renum) const
 {
   MEDCouplingAutoRefCountObjectPtr<DataArrayInt> eltsToKeep=_fam->getIdsEqualList(idsBg,idsEnd);
-  MEDCouplingUMesh *m=(MEDCouplingUMesh *)_m_by_types->buildPartOfMySelf(eltsToKeep->getConstPointer(),eltsToKeep->getConstPointer()+eltsToKeep->getNumberOfTuples(),true);
+  MEDCouplingUMesh *m=(MEDCouplingUMesh *)_m_by_types.getUmesh()->buildPartOfMySelf(eltsToKeep->getConstPointer(),eltsToKeep->getConstPointer()+eltsToKeep->getNumberOfTuples(),true);
   if(renum)
     return renumIfNeeded(m,eltsToKeep->getConstPointer());
   return m;
@@ -769,7 +738,7 @@ MEDCouplingUMesh *MEDFileUMeshSplitL1::getWholeMesh(bool renum) const
   if(renum && ((const DataArrayInt *)_num))
     tmp=_m;
   else
-    tmp=_m_by_types;
+    { tmp=_m_by_types.getUmesh(); if(tmp) tmp->incrRef(); }
   return tmp.retn();
 }
 
@@ -777,10 +746,7 @@ DataArrayInt *MEDFileUMeshSplitL1::getOrCreateAndGetFamilyField() throw(INTERP_K
 {
   if((DataArrayInt *)_fam)
     return _fam;
-  MEDCouplingUMesh *m(_m_by_types);
-  if(!m)
-    throw INTERP_KERNEL::Exception("MEDFileUMeshSplitL1::getOrCreateAndGetFamilyField : impossible to create a family field array because no mesh specified on this level !");
-  int nbOfTuples=m->getNumberOfCells();
+  int nbOfTuples=_m_by_types.getSize();
   _fam=DataArrayInt::New(); _fam->alloc(nbOfTuples,1); _fam->fillWithZero();
   return _fam;
 }
@@ -833,10 +799,9 @@ void MEDFileUMeshSplitL1::setGroupsFromScratch(const std::vector<const MEDCoupli
 
 void MEDFileUMeshSplitL1::write(med_idt fid, const char *mName, int mdim) const
 {
-  std::vector<MEDCouplingUMesh *> ms=_m_by_types->splitByType();
-  std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> > msMSafe(ms.begin(),ms.end());
+  std::vector<MEDCoupling1GTUMesh *> ms(_m_by_types.getParts());
   int start=0;
-  for(std::vector<MEDCouplingUMesh *>::const_iterator it=ms.begin();it!=ms.end();it++)
+  for(std::vector<MEDCoupling1GTUMesh *>::const_iterator it=ms.begin();it!=ms.end();it++)
     {
       int nbCells=(*it)->getNumberOfCells();
       int end=start+nbCells;
@@ -848,14 +813,14 @@ void MEDFileUMeshSplitL1::write(med_idt fid, const char *mName, int mdim) const
         num=_num->substr(start,end);
       if((const DataArrayAsciiChar *)_names)
         names=static_cast<DataArrayAsciiChar *>(_names->substr(start,end));
-      MEDFileUMeshPerType::write(fid,mName,mdim,(*it),fam,num,names);
+      MEDFileUMeshPerType::Write(fid,mName,mdim,(*it),fam,num,names);
       start=end;
     }
 }
 
 void MEDFileUMeshSplitL1::renumberNodesInConn(const int *newNodeNumbersO2N) throw(INTERP_KERNEL::Exception)
 {
-  MEDCouplingUMesh *m(_m_by_types);
+  MEDCouplingUMesh *m(_m_by_types.getUmesh());
   if(!m)
     return;
   m->renumberNodesInConn(newNodeNumbersO2N);
@@ -875,10 +840,8 @@ void MEDFileUMeshSplitL1::setFamilyArr(DataArrayInt *famArr)
       _fam=0;
       return ;
     }
-  MEDCouplingUMesh *mbt(_m_by_types);
-  if(!mbt)
-    throw INTERP_KERNEL::Exception("MEDFileUMeshSplitL1::setFamilyArr : no mesh defined on this level !");
-  famArr->checkNbOfTuplesAndComp(mbt->getNumberOfCells(),1,"MEDFileUMeshSplitL1::setFamilyArr : Problem in size of Family arr ! ");
+  int sz(_m_by_types.getSize());
+  famArr->checkNbOfTuplesAndComp(sz,1,"MEDFileUMeshSplitL1::setFamilyArr : Problem in size of Family arr ! ");
   famArr->incrRef();
   _fam=famArr;
 }
@@ -891,10 +854,8 @@ void MEDFileUMeshSplitL1::setRenumArr(DataArrayInt *renumArr)
       _rev_num=0;
       return ;
     }
-  MEDCouplingUMesh *mbt(_m_by_types);
-  if(!mbt)
-    throw INTERP_KERNEL::Exception("MEDFileUMeshSplitL1::setRenumArr : no mesh defined on this level !");
-  renumArr->checkNbOfTuplesAndComp(mbt->getNumberOfCells(),1,"MEDFileUMeshSplitL1::setRenumArr : Problem in size of numbering arr ! ");
+  int sz(_m_by_types.getSize());
+  renumArr->checkNbOfTuplesAndComp(sz,1,"MEDFileUMeshSplitL1::setRenumArr : Problem in size of numbering arr ! ");
   renumArr->incrRef();
   _num=renumArr;
   computeRevNum();
@@ -907,10 +868,8 @@ void MEDFileUMeshSplitL1::setNameArr(DataArrayAsciiChar *nameArr)
       _names=0;
       return ;
     }
-  MEDCouplingUMesh *mbt(_m_by_types);
-  if(!mbt)
-    throw INTERP_KERNEL::Exception("MEDFileUMeshSplitL1::setNameArr : no mesh defined on this level !");
-  nameArr->checkNbOfTuplesAndComp(mbt->getNumberOfCells(),MED_SNAME_SIZE,"MEDFileUMeshSplitL1::setNameArr : Problem in size of name arr ! ");
+  int sz(_m_by_types.getSize());
+  nameArr->checkNbOfTuplesAndComp(sz,MED_SNAME_SIZE,"MEDFileUMeshSplitL1::setNameArr : Problem in size of name arr ! ");
   nameArr->incrRef();
   _names=nameArr;
 }
@@ -966,7 +925,7 @@ void MEDFileUMeshSplitL1::TraduceFamilyNumber(const std::vector< std::vector<int
                                               std::map<int,int>& famIdTrad, std::map<int,std::string>& newfams)
 {
   std::set<int> allfids;
-  
+  //tony
 }
 
 void MEDFileUMeshSplitL1::computeRevNum() const
@@ -975,3 +934,306 @@ void MEDFileUMeshSplitL1::computeRevNum() const
   int maxValue=_num->getMaxValue(pos);
   _rev_num=_num->invertArrayN2O2O2N(maxValue+1);
 }
+
+//=
+
+MEDFileUMeshAggregateCompute::MEDFileUMeshAggregateCompute():_mp_time(0),_m_time(0)
+{
+}
+
+void MEDFileUMeshAggregateCompute::assignParts(const std::vector< const MEDCoupling1GTUMesh * >& mParts)
+{
+  std::size_t sz(mParts.size());
+  std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> > ret(sz);
+  for(std::size_t i=0;i<sz;i++)
+    {
+      const MEDCoupling1GTUMesh *elt(mParts[i]);
+      if(!elt)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::assignParts : presence of null pointer !");
+      ret[i]=const_cast<MEDCoupling1GTUMesh *>(elt); elt->incrRef();
+    }
+  _m_parts=ret;
+  _mp_time=std::max(_mp_time,_m_time)+1;
+  _m=0;
+}
+
+void MEDFileUMeshAggregateCompute::assignUMesh(MEDCouplingUMesh *m)
+{
+  _m=m;
+  _m_parts.clear();
+  _m_time=std::max(_mp_time,_m_time)+1;
+}
+
+MEDCouplingUMesh *MEDFileUMeshAggregateCompute::getUmesh() const
+{
+  if(_mp_time<=_m_time)
+    return _m;
+  std::vector< const MEDCoupling1GTUMesh *> mp(_m_parts.size());
+  std::copy(_m_parts.begin(),_m_parts.end(),mp.begin());
+  _m=MEDCoupling1GTUMesh::AggregateOnSameCoordsToUMesh(mp);
+  _m_parts.clear();//to avoid memory peak !
+  _m_time=_mp_time+1;//+1 is important ! That is to say that only _m is OK not _m_parts because cleared !
+  return _m;
+}
+
+std::vector<MEDCoupling1GTUMesh *> MEDFileUMeshAggregateCompute::getParts() const
+{
+  if(_mp_time>=_m_time)
+    {
+      std::vector<MEDCoupling1GTUMesh *> ret(_m_parts.size());
+      std::size_t i(0);
+      for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::const_iterator it=_m_parts.begin();it!=_m_parts.end();it++,i++)
+        {
+          const MEDCoupling1GTUMesh *elt(*it);
+          ret[i]=const_cast<MEDCoupling1GTUMesh *>(elt);
+        }
+      return ret;
+    }
+  forceComputationOfPartsFromUMesh();
+  std::vector<MEDCoupling1GTUMesh *> ret(_m_parts.size());
+  std::size_t i(0);
+  for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::const_iterator it=_m_parts.begin();it!=_m_parts.end();it++,i++)
+    {
+      const MEDCoupling1GTUMesh *elt(*it);
+      ret[i]=const_cast<MEDCoupling1GTUMesh *>(elt);
+    }
+  return ret;
+}
+
+void MEDFileUMeshAggregateCompute::forceComputationOfPartsFromUMesh() const
+{
+  const MEDCouplingUMesh *m(_m);
+  if(!m)
+    throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::forceComputationOfPartsFromUMesh : null UMesh !");
+  std::vector<MEDCouplingUMesh *> ms(m->splitByType());
+  std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> > msMSafe(ms.begin(),ms.end());
+  std::size_t sz(msMSafe.size());
+  _m_parts.resize(sz);
+  for(std::size_t i=0;i<sz;i++)
+    _m_parts[i]=MEDCoupling1GTUMesh::New(ms[i]);
+  _mp_time=std::max(_mp_time,_m_time)+1;
+}
+
+std::size_t MEDFileUMeshAggregateCompute::getTimeOfThis() const
+{
+  if(_mp_time>_m_time)
+    return getTimeOfParts();
+  if(_m_time>_mp_time)
+    return getTimeOfUMesh();
+  return std::max(getTimeOfParts(),getTimeOfUMesh());
+}
+
+std::size_t MEDFileUMeshAggregateCompute::getTimeOfParts() const
+{
+  std::size_t ret(0);
+  for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::const_iterator it=_m_parts.begin();it!=_m_parts.end();it++)
+    {
+      const MEDCoupling1GTUMesh *elt(*it);
+      if(!elt)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getTimeOfParts : null obj in parts !");
+      ret=std::max(ret,elt->getTimeOfThis());
+    }
+  if(ret==0)
+    throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getTimeOfParts : parts is empty !");
+  return ret;
+}
+
+std::size_t MEDFileUMeshAggregateCompute::getTimeOfUMesh() const
+{
+  const MEDCouplingUMesh *m(_m);
+  if(!m)
+    throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getTimeOfUMesh : unmesh is null !");
+  return m->getTimeOfThis();
+}
+
+/*!
+ * Coordinates pointer is not counted because father instance already count it !
+ */
+std::size_t MEDFileUMeshAggregateCompute::getHeapMemorySize() const
+{ 
+  std::size_t ret(0);
+  ret+=_m_parts.size()*sizeof(MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh>);
+  std::size_t sz(_m_parts.size());
+  for(std::size_t i=0;i<sz;i++)
+    {
+      const MEDCoupling1GTUMesh *pt(_m_parts[i]);
+      if(pt)
+        {
+          ret+=pt->getHeapMemorySize();
+          const DataArrayDouble *coo(pt->getCoords());
+          if(coo)
+            ret-=coo->getHeapMemorySize();
+        }
+    }
+  const MEDCouplingUMesh *m(_m);
+  if(m)
+    {
+      ret+=m->getHeapMemorySize();
+      const DataArrayDouble *coo(m->getCoords());
+      if(coo)
+            ret-=coo->getHeapMemorySize();
+    }
+  return ret;
+}
+
+MEDFileUMeshAggregateCompute MEDFileUMeshAggregateCompute::deepCpy(DataArrayDouble *coords) const
+{
+  MEDFileUMeshAggregateCompute ret;
+  ret._m_parts.resize(_m_parts.size());
+  for(std::size_t i=0;i<_m_parts.size();i++)
+    {
+      const MEDCoupling1GTUMesh *elt(_m_parts[i]);
+      if(elt)
+        {
+          ret._m_parts[i]=static_cast<ParaMEDMEM::MEDCoupling1GTUMesh*>(elt->deepCpy());
+          ret._m_parts[i]->setCoords(coords);
+        }
+    }
+  ret._mp_time=_mp_time; ret._m_time=_m_time;
+  if((const MEDCouplingUMesh *)_m)
+    {
+      ret._m=static_cast<ParaMEDMEM::MEDCouplingUMesh*>(_m->deepCpy());
+      ret._m->setCoords(coords);
+    }
+  return ret;
+}
+
+bool MEDFileUMeshAggregateCompute::isEqual(const MEDFileUMeshAggregateCompute& other, double eps, std::string& what) const
+{
+  const MEDCouplingUMesh *m1(getUmesh());
+  const MEDCouplingUMesh *m2(other.getUmesh());
+  if((m1==0 && m2!=0) || (m1!=0 && m2==0))
+    {
+      what="Presence of mesh in one sublevel and not in other!";
+      return false;
+    }
+  if(m1)
+    {
+      std::string what2;
+      if(!m1->isEqualIfNotWhy(m2,eps,what2))
+        {
+          what=std::string("meshes at a sublevel are not deeply equal (")+what2+std::string(")!");
+          return false;
+        }
+    }
+  return true;
+}
+
+void MEDFileUMeshAggregateCompute::clearNonDiscrAttributes() const
+{
+  for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::const_iterator it=_m_parts.begin();it!=_m_parts.end();it++)
+    MEDFileUMeshSplitL1::ClearNonDiscrAttributes(*it);
+  MEDFileUMeshSplitL1::ClearNonDiscrAttributes(_m);
+}
+
+void MEDFileUMeshAggregateCompute::synchronizeTinyInfo(const MEDFileMesh& master) const
+{
+  for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::const_iterator it=_m_parts.begin();it!=_m_parts.end();it++)
+    {
+      const MEDCoupling1GTUMesh *tmp(*it);
+      if(tmp)
+        {
+          (const_cast<MEDCoupling1GTUMesh *>(tmp))->setName(master.getName());
+          (const_cast<MEDCoupling1GTUMesh *>(tmp))->setDescription(master.getDescription());
+          (const_cast<MEDCoupling1GTUMesh *>(tmp))->setTime(master.getTimeValue(),master.getIteration(),master.getOrder());
+          (const_cast<MEDCoupling1GTUMesh *>(tmp))->setTimeUnit(master.getTimeUnit());
+        }
+    }
+  const MEDCouplingUMesh *m(_m);
+  if(m)
+    {
+      (const_cast<MEDCouplingUMesh *>(m))->setName(master.getName());
+      (const_cast<MEDCouplingUMesh *>(m))->setDescription(master.getDescription());
+      (const_cast<MEDCouplingUMesh *>(m))->setTime(master.getTimeValue(),master.getIteration(),master.getOrder());
+      (const_cast<MEDCouplingUMesh *>(m))->setTimeUnit(master.getTimeUnit());
+    }
+}
+
+bool MEDFileUMeshAggregateCompute::empty() const
+{
+  if(_mp_time<_m_time)
+    return ((const MEDCouplingUMesh *)_m)==0;
+  //else _mp_time>=_m_time)
+  return _m_parts.empty();
+  
+}
+
+int MEDFileUMeshAggregateCompute::getMeshDimension() const
+{
+  if(_mp_time<_m_time)
+    {
+      const MEDCouplingUMesh *m(_m);
+      if(!m)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getMeshDimension : no umesh in this !");
+      return m->getMeshDimension();
+    }
+  else
+    {
+      if(_m_parts.empty())
+        throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getMeshDimension : part mesh is empty !");
+      const MEDCoupling1GTUMesh *m(_m_parts[0]);
+      if(!m)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getMeshDimension : part mesh contains null instance !");
+      return m->getMeshDimension();
+    }
+}
+
+std::vector<int> MEDFileUMeshAggregateCompute::getDistributionOfTypes() const
+{
+  if(_mp_time<_m_time)
+    {
+      const MEDCouplingUMesh *m(_m);
+      if(!m)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getDistributionOfTypes : no umesh in this !");
+      return m->getDistributionOfTypes();
+    }
+  else
+    {
+      std::vector<int> ret;
+      for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::const_iterator it=_m_parts.begin();it!=_m_parts.end();it++)
+        {
+          const MEDCoupling1GTUMesh *tmp(*it);
+          if(!tmp)
+            throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getDistributionOfTypes : part mesh contains null instance !");
+          std::vector<int> ret0(tmp->getDistributionOfTypes());
+          ret.insert(ret.end(),ret0.begin(),ret0.end());
+        }
+      return ret;
+    }
+}
+
+int MEDFileUMeshAggregateCompute::getSize() const throw(INTERP_KERNEL::Exception)
+{
+  if(_mp_time<_m_time)
+    {
+      const MEDCouplingUMesh *m(_m);
+      if(!m)
+        throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getSize : no umesh in this !");
+      return m->getNumberOfCells();
+    }
+  else
+    {
+      int ret=0;
+      for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::const_iterator it=_m_parts.begin();it!=_m_parts.end();it++)
+        {
+          const MEDCoupling1GTUMesh *m(*it);
+          if(!m)
+            throw INTERP_KERNEL::Exception("MEDFileUMeshAggregateCompute::getSize : part mesh contains null instance !");
+          ret+=m->getNumberOfCells();
+        }
+      return ret;
+    }
+}
+
+void MEDFileUMeshAggregateCompute::setCoords(DataArrayDouble *coords) throw(INTERP_KERNEL::Exception)
+{
+  for(std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> >::iterator it=_m_parts.begin();it!=_m_parts.end();it++)
+    {
+      MEDCoupling1GTUMesh *tmp(*it);
+      if(tmp)
+        (*it)->setCoords(coords);
+    }
+  MEDCouplingUMesh *m(_m);
+  if(m)
+    m->setCoords(coords);
+}
diff --git a/src/MEDLoader/MEDFileMeshLL.hxx b/src/MEDLoader/MEDFileMeshLL.hxx
index 815fa08a9..896398aa4 100644
--- a/src/MEDLoader/MEDFileMeshLL.hxx
+++ b/src/MEDLoader/MEDFileMeshLL.hxx
@@ -26,6 +26,7 @@
 
 #include "MEDCouplingUMesh.hxx"
 #include "MEDCouplingCMesh.hxx"
+#include "MEDCoupling1GTUMesh.hxx"
 #include "MEDCouplingCurveLinearMesh.hxx"
 #include "MEDCouplingAutoRefCountObjectPtr.hxx"
 
@@ -130,11 +131,41 @@ namespace ParaMEDMEM
     void updateTime() const;
   private:
     const MEDFileUMeshSplitL1 *_st;
-    mutable unsigned int _mpt_time;
-    mutable unsigned int _num_time;
+    mutable std::size_t _mpt_time;
+    mutable std::size_t _num_time;
     mutable MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> _m;
   };
 
+  class MEDFileUMeshAggregateCompute
+  {
+  public:
+    MEDFileUMeshAggregateCompute();
+    void assignParts(const std::vector< const MEDCoupling1GTUMesh * >& mParts);
+    void assignUMesh(MEDCouplingUMesh *m);
+    MEDCouplingUMesh *getUmesh() const;
+    std::vector<MEDCoupling1GTUMesh *> getParts() const;
+    std::size_t getTimeOfThis() const;
+    std::size_t getHeapMemorySize() const;
+    MEDFileUMeshAggregateCompute deepCpy(DataArrayDouble *coords) const;
+    bool isEqual(const MEDFileUMeshAggregateCompute& other, double eps, std::string& what) const;
+    void clearNonDiscrAttributes() const;
+    void synchronizeTinyInfo(const MEDFileMesh& master) const;
+    bool empty() const;
+    int getMeshDimension() const;
+    std::vector<int> getDistributionOfTypes() const;
+    int getSize() const throw(INTERP_KERNEL::Exception);
+    void setCoords(DataArrayDouble *coords) throw(INTERP_KERNEL::Exception);
+  private:
+    void forceComputationOfPartsFromUMesh() const;
+    std::size_t getTimeOfParts() const;
+    std::size_t getTimeOfUMesh() const;
+  private:
+    mutable std::vector< MEDCouplingAutoRefCountObjectPtr<MEDCoupling1GTUMesh> > _m_parts;
+    mutable std::size_t _mp_time;
+    mutable std::size_t _m_time;
+    mutable MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> _m;
+  };
+  
   class MEDFileUMeshSplitL1 : public RefCountObject
   {
     friend class MEDFileUMeshPermCompute;
@@ -144,7 +175,8 @@ namespace ParaMEDMEM
     MEDFileUMeshSplitL1(MEDCouplingUMesh *m);
     MEDFileUMeshSplitL1(MEDCouplingUMesh *m, bool newOrOld);
     std::size_t getHeapMemorySize() const;
-    MEDFileUMeshSplitL1 *deepCpy() const;
+    MEDFileUMeshSplitL1 *deepCpy(DataArrayDouble *coords) const;
+    void setCoords(DataArrayDouble *coords) throw(INTERP_KERNEL::Exception);
     bool isEqual(const MEDFileUMeshSplitL1 *other, double eps, std::string& what) const;
     void clearNonDiscrAttributes() const;
     void synchronizeTinyInfo(const MEDFileMesh& master) const;
@@ -185,7 +217,7 @@ namespace ParaMEDMEM
     DataArrayInt *renumIfNeededArr(const DataArrayInt *da) const;
     void computeRevNum() const;
   private:
-    MEDCouplingAutoRefCountObjectPtr<MEDCouplingUMesh> _m_by_types;
+    MEDFileUMeshAggregateCompute _m_by_types;
     MEDCouplingAutoRefCountObjectPtr<DataArrayInt> _fam;
     MEDCouplingAutoRefCountObjectPtr<DataArrayInt> _num;
     MEDCouplingAutoRefCountObjectPtr<DataArrayAsciiChar> _names;
diff --git a/src/MEDLoader/Swig/MEDLoaderTest3.py b/src/MEDLoader/Swig/MEDLoaderTest3.py
index 4e998d646..4769c1bee 100644
--- a/src/MEDLoader/Swig/MEDLoaderTest3.py
+++ b/src/MEDLoader/Swig/MEDLoaderTest3.py
@@ -3162,7 +3162,12 @@ class MEDLoaderTest(unittest.TestCase):
         mm.write(fname,2)
         ##
         mm=MEDFileMesh.New(fname,"mesh",-1,-1,MEDFileMeshReadSelector())
+        b4_ref_heap_mem=mm.getHeapMemorySize()
+        mm.getMeshAtLevel(0)## please let this line : force to move 1GTUMesh -> UMesh
+        mm.getMeshAtLevel(-1)## please let this line : force to move 1GTUMesh -> UMesh
         ref_heap_mem=mm.getHeapMemorySize()
+        # check the gain of memory using 1GTUMesh instead of UMesh
+        self.assertTrue(ref_heap_mem-b4_ref_heap_mem>=(32+9)*4*2-32)# 32+9=nbCells 4=sizeof(int) 2=the types+index -32=loss linked to vector
         #
         mm=MEDFileMesh.New(fname,MEDFileMeshReadSelector(0))
         self.assertEqual(len(mm.getGroupsNames()),0)
-- 
2.39.2