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22806: EDF SMESH: Regression: Prism_3D error
[modules/smesh.git] / src / SMESH / SMESH_subMesh.cxx
index 65ffac712f0240230d5e2296957ad7f026e09241..0d4e2d120877f027f7f48970005a25a6a6963d3b 100644 (file)
@@ -1,4 +1,4 @@
-// Copyright (C) 2007-2012  CEA/DEN, EDF R&D, OPEN CASCADE
+// Copyright (C) 2007-2014  CEA/DEN, EDF R&D, OPEN CASCADE
 //
 // Copyright (C) 2003-2007  OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN,
 // CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS
@@ -6,7 +6,7 @@
 // This library is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Lesser General Public
 // License as published by the Free Software Foundation; either
-// version 2.1 of the License.
+// version 2.1 of the License, or (at your option) any later version.
 //
 // This library is distributed in the hope that it will be useful,
 // but WITHOUT ANY WARRANTY; without even the implied warranty of
 #include <BRep_Builder.hxx>
 #include <BRep_Tool.hxx>
 #include <TopExp.hxx>
+#include <TopExp_Explorer.hxx>
 #include <TopTools_IndexedMapOfShape.hxx>
 #include <TopTools_ListIteratorOfListOfShape.hxx>
+#include <TopTools_ListOfShape.hxx>
 #include <TopoDS.hxx>
 #include <TopoDS_Compound.hxx>
-#include <gp_Pnt.hxx>
-#include <TopExp_Explorer.hxx>
 #include <TopoDS_Iterator.hxx>
+#include <gp_Pnt.hxx>
 
 #include <Standard_OutOfMemory.hxx>
 #include <Standard_ErrorHandler.hxx>
@@ -88,22 +89,24 @@ SMESH_subMesh::SMESH_subMesh(int                  Id,
                              SMESHDS_Mesh *       meshDS,
                              const TopoDS_Shape & aSubShape)
 {
-        _subShape = aSubShape;
-        _subMeshDS = meshDS->MeshElements(_subShape);   // may be null ...
-        _father = father;
-        _Id = Id;
-        _dependenceAnalysed = _alwaysComputed = false;
-
-        if (_subShape.ShapeType() == TopAbs_VERTEX)
-        {
-                _algoState = HYP_OK;
-                _computeState = READY_TO_COMPUTE;
-        }
-        else
-        {
-          _algoState = NO_ALGO;
-          _computeState = NOT_READY;
-        }
+  _subShape           = aSubShape;
+  _subMeshDS          = meshDS->MeshElements(_subShape);   // may be null ...
+  _father             = father;
+  _Id                 = Id;
+  _dependenceAnalysed = _alwaysComputed = false;
+  _algo               = 0;
+  if (_subShape.ShapeType() == TopAbs_VERTEX)
+  {
+    _algoState = HYP_OK;
+    _computeState = READY_TO_COMPUTE;
+  }
+  else
+  {
+    _algoState = NO_ALGO;
+    _computeState = NOT_READY;
+  }
+  _computeCost = 0; // how costly is to compute this sub-mesh
+  _realComputeCost = 0;
 }
 
 //=============================================================================
@@ -114,8 +117,6 @@ SMESH_subMesh::SMESH_subMesh(int                  Id,
 
 SMESH_subMesh::~SMESH_subMesh()
 {
-  MESSAGE("SMESH_subMesh::~SMESH_subMesh");
-  // ****
   deleteOwnListeners();
 }
 
@@ -149,6 +150,17 @@ SMESHDS_SubMesh * SMESH_subMesh::GetSubMeshDS()
  */
 //=============================================================================
 
+const SMESHDS_SubMesh * SMESH_subMesh::GetSubMeshDS() const
+{
+  return ((SMESH_subMesh*) this )->GetSubMeshDS();
+}
+
+//=============================================================================
+/*!
+ *
+ */
+//=============================================================================
+
 SMESHDS_SubMesh* SMESH_subMesh::CreateSubMeshDS()
 {
   if ( !GetSubMeshDS() ) {
@@ -183,7 +195,12 @@ SMESH_subMesh *SMESH_subMesh::GetFirstToCompute()
 
 SMESH_Algo* SMESH_subMesh::GetAlgo() const
 {
-  return _father->GetGen()->GetAlgo(*_father, _subShape);
+  if ( !_algo )
+  {
+    SMESH_subMesh* me = const_cast< SMESH_subMesh* >( this );
+    me->_algo = _father->GetGen()->GetAlgo( me );
+  }
+  return _algo;
 }
 
 //================================================================================
@@ -253,15 +270,16 @@ bool SMESH_subMesh::IsMeshComputed() const
 
 //=============================================================================
 /*!
- *
+ * Return true if all sub-meshes have been meshed
  */
 //=============================================================================
 
-bool SMESH_subMesh::subMeshesComputed()
+bool SMESH_subMesh::SubMeshesComputed(bool * isFailedToCompute/*=0*/) const
 {
   int myDim = SMESH_Gen::GetShapeDim( _subShape );
   int dimToCheck = myDim - 1;
   bool subMeshesComputed = true;
+  if ( isFailedToCompute ) *isFailedToCompute = false;
   // check subMeshes with upper dimension => reverse iteration
   SMESH_subMeshIteratorPtr smIt = getDependsOnIterator(false,true);
   while ( smIt->more() )
@@ -270,69 +288,117 @@ bool SMESH_subMesh::subMeshesComputed()
     if ( sm->_alwaysComputed )
       continue;
     const TopoDS_Shape & ss = sm->GetSubShape();
+
     // MSV 07.04.2006: restrict checking to myDim-1 only. Ex., there is no sense
     // in checking of existence of edges if the algo needs only faces. Moreover,
     // degenerated edges may have no submesh, as after computing NETGEN_2D.
-    int dim = SMESH_Gen::GetShapeDim( ss );
-    if (dim < dimToCheck)
-      break; // the rest subMeshes are all of less dimension
+    if ( !_algo || _algo->NeedDiscreteBoundary() ) {
+      int dim = SMESH_Gen::GetShapeDim( ss );
+      if (dim < dimToCheck)
+        break; // the rest subMeshes are all of less dimension
+    }
     SMESHDS_SubMesh * ds = sm->GetSubMeshDS();
     bool computeOk = (sm->GetComputeState() == COMPUTE_OK ||
                       (ds && ( dimToCheck ? ds->NbElements() : ds->NbNodes()  )));
     if (!computeOk)
     {
-      int type = ss.ShapeType();
-
       subMeshesComputed = false;
+      if ( isFailedToCompute && !(*isFailedToCompute) )
+        *isFailedToCompute = ( sm->GetComputeState() == FAILED_TO_COMPUTE );
+
+      // int type = ss.ShapeType();
+
+      // switch (type)
+      // {
+      // case TopAbs_COMPOUND:
+      //   {
+      //     MESSAGE("The not computed sub mesh is a COMPOUND");
+      //     break;
+      //   }
+      // case TopAbs_COMPSOLID:
+      //   {
+      //     MESSAGE("The not computed sub mesh is a COMPSOLID");
+      //     break;
+      //   }
+      // case TopAbs_SHELL:
+      //   {
+      //     MESSAGE("The not computed sub mesh is a SHEL");
+      //     break;
+      //   }
+      // case TopAbs_WIRE:
+      //   {
+      //     MESSAGE("The not computed sub mesh is a WIRE");
+      //     break;
+      //   }
+      // case TopAbs_SOLID:
+      //   {
+      //     MESSAGE("The not computed sub mesh is a SOLID");
+      //     break;
+      //   }
+      // case TopAbs_FACE:
+      //   {
+      //     MESSAGE("The not computed sub mesh is a FACE");
+      //     break;
+      //   }
+      // case TopAbs_EDGE:
+      //   {
+      //     MESSAGE("The not computed sub mesh is a EDGE");
+      //     break;
+      //   }
+      // default:
+      //   {
+      //     MESSAGE("The not computed sub mesh is of unknown type");
+      //     break;
+      //   }
+      // }
+
+      if ( !isFailedToCompute )
+        break;
+    }
+  }
+  return subMeshesComputed;
+}
 
-      switch (type)
-      {
-      case TopAbs_COMPOUND:
-        {
-          MESSAGE("The not computed sub mesh is a COMPOUND");
-          break;
-        }
-      case TopAbs_COMPSOLID:
-        {
-          MESSAGE("The not computed sub mesh is a COMPSOLID");
-          break;
-        }
-      case TopAbs_SHELL:
-        {
-          MESSAGE("The not computed sub mesh is a SHEL");
-          break;
-        }
-      case TopAbs_WIRE:
-        {
-          MESSAGE("The not computed sub mesh is a WIRE");
-          break;
-        }
-      case TopAbs_SOLID:
-        {
-          MESSAGE("The not computed sub mesh is a SOLID");
-          break;
-        }
-      case TopAbs_FACE:
-        {
-          MESSAGE("The not computed sub mesh is a FACE");
-          break;
-        }
-      case TopAbs_EDGE:
-        {
-          MESSAGE("The not computed sub mesh is a EDGE");
-          break;
-        }
-      default:
-        {
-          MESSAGE("The not computed sub mesh is of unknown type");
-          break;
-        }
-      }
+//================================================================================
+/*!
+ * \brief Return cost of computing this sub-mesh. If hypotheses are not well defined,
+ *        zero is returned
+ *  \return int - the computation cost in abstract units.
+ */
+//================================================================================
 
-      break;
+int SMESH_subMesh::GetComputeCost() const
+{
+  return _realComputeCost;
+}
+
+//================================================================================
+/*!
+ * \brief Return cost of computing this sub-mesh. The cost depends on the shape type
+ *        and number of sub-meshes this one DependsOn().
+ *  \return int - the computation cost in abstract units.
+ */
+//================================================================================
+
+int SMESH_subMesh::computeCost() const
+{
+  if ( !_computeCost )
+  {
+    int computeCost;
+    switch ( _subShape.ShapeType() ) {
+    case TopAbs_SOLID:
+    case TopAbs_SHELL: computeCost = 5000; break;
+    case TopAbs_FACE:  computeCost = 500; break;
+    case TopAbs_EDGE:  computeCost = 2; break;
+    default:           computeCost = 1;
     }
+    SMESH_subMeshIteratorPtr childIt = getDependsOnIterator(/*includeSelf=*/false);
+    while ( childIt->more() )
+      computeCost += childIt->next()->computeCost();
+
+    ((SMESH_subMesh*)this)->_computeCost = computeCost;
   }
-  return subMeshesComputed;
+  return _computeCost;
 }
 
 //=============================================================================
@@ -406,6 +472,10 @@ const map < int, SMESH_subMesh * >& SMESH_subMesh::DependsOn()
       {
         insertDependence(exp.Current());
       }
+      for (TopExp_Explorer exp(_subShape, TopAbs_VERTEX, TopAbs_EDGE); exp.More();exp.Next())
+      {
+        insertDependence(exp.Current());
+      }
       break;
     }
   case TopAbs_COMPSOLID:
@@ -477,6 +547,23 @@ const map < int, SMESH_subMesh * >& SMESH_subMesh::DependsOn()
   return _mapDepend;
 }
 
+//================================================================================
+/*!
+ * \brief Return a key for SMESH_subMesh::_mapDepend map
+ */
+//================================================================================
+
+namespace {
+  int dependsOnMapKey( const SMESH_subMesh* sm )
+  {
+    int type = sm->GetSubShape().ShapeType();
+    int ordType = 9 - type;               // 2 = Vertex, 8 = CompSolid
+    int cle = sm->GetId();
+    cle += 10000000 * ordType;    // sort map by ordType then index
+    return cle;
+  }
+}
+
 //=============================================================================
 /*!
  * For simple Shapes (solid, face, edge): add subMesh into dependence list.
@@ -486,10 +573,7 @@ const map < int, SMESH_subMesh * >& SMESH_subMesh::DependsOn()
 void SMESH_subMesh::insertDependence(const TopoDS_Shape aSubShape)
 {
   SMESH_subMesh *aSubMesh = _father->GetSubMesh(aSubShape);
-  int type = aSubShape.ShapeType();
-  int ordType = 9 - type;               // 2 = Vertex, 8 = CompSolid
-  int cle = aSubMesh->GetId();
-  cle += 10000000 * ordType;    // sort map by ordType then index
+  int cle = dependsOnMapKey( aSubMesh );
   if ( _mapDepend.find( cle ) == _mapDepend.end())
   {
     _mapDepend[cle] = aSubMesh;
@@ -498,19 +582,28 @@ void SMESH_subMesh::insertDependence(const TopoDS_Shape aSubShape)
   }
 }
 
+//================================================================================
+/*!
+ * \brief Return \c true if \a this sub-mesh depends on \a other
+ */
+//================================================================================
+
+bool SMESH_subMesh::DependsOn( const SMESH_subMesh* other ) const
+{
+  return other ? _mapDepend.count( dependsOnMapKey( other )) : false;
+}
+
 //=============================================================================
 /*!
- *
+ * Return a shape of \a this sub-mesh
  */
 //=============================================================================
 
 const TopoDS_Shape & SMESH_subMesh::GetSubShape() const
 {
-        //MESSAGE("SMESH_subMesh::GetSubShape");
-        return _subShape;
+  return _subShape;
 }
 
-
 //=======================================================================
 //function : CanAddHypothesis
 //purpose  : return true if theHypothesis can be attached to me:
@@ -577,19 +670,21 @@ bool SMESH_subMesh::IsApplicableHypotesis(const SMESH_Hypothesis* theHypothesis,
   return false;
 }
 
-//=============================================================================
+//================================================================================
 /*!
- *
+ * \brief Treats modification of hypotheses definition
+ *  \param [in] event - what happens
+ *  \param [in] anHyp - a hypothesis
+ *  \return SMESH_Hypothesis::Hypothesis_Status - a treatment result.
+ * 
+ * Optional description of a problematic situation (if any) can be retrieved
+ * via GetComputeError().
  */
-//=============================================================================
+//================================================================================
 
 SMESH_Hypothesis::Hypothesis_Status
   SMESH_subMesh::AlgoStateEngine(int event, SMESH_Hypothesis * anHyp)
 {
-  //  MESSAGE("SMESH_subMesh::AlgoStateEngine");
-  //SCRUTE(_algoState);
-  //SCRUTE(event);
-
   // **** les retour des evenement shape sont significatifs
   // (add ou remove fait ou non)
   // le retour des evenement father n'indiquent pas que add ou remove fait
@@ -597,8 +692,8 @@ SMESH_Hypothesis::Hypothesis_Status
   SMESH_Hypothesis::Hypothesis_Status aux_ret, ret = SMESH_Hypothesis::HYP_OK;
 
   SMESHDS_Mesh* meshDS =_father->GetMeshDS();
-  //SMESH_Gen*    gen    =_father->GetGen();
   SMESH_Algo*   algo   = 0;
+  _algo = 0;
 
   if (_subShape.ShapeType() == TopAbs_VERTEX )
   {
@@ -627,7 +722,7 @@ SMESH_Hypothesis::Hypothesis_Status
 
   int oldAlgoState = _algoState;
   bool modifiedHyp = (event == MODIF_HYP);  // if set to true, force event MODIF_ALGO_STATE
-  bool needFullClean = false;
+  SMESH_Algo* algoRequiringCleaning = 0;
 
   bool isApplicableHyp = IsApplicableHypotesis( anHyp );
 
@@ -650,8 +745,9 @@ SMESH_Hypothesis::Hypothesis_Status
       SMESH_HypoFilter filter( SMESH_HypoFilter::HasType( algo->GetType() ));
       filter.Or( SMESH_HypoFilter::HasType( algo->GetType()+1 ));
       filter.Or( SMESH_HypoFilter::HasType( algo->GetType()+2 ));
-      if ( SMESH_Algo * curAlgo = (SMESH_Algo*) _father->GetHypothesis( _subShape, filter, true ))
-        needFullClean = ( !curAlgo->NeedDiscreteBoundary() );
+      if ( SMESH_Algo * curAlgo = (SMESH_Algo*)_father->GetHypothesis( this, filter, true ))
+        if ( !curAlgo->NeedDiscreteBoundary() )
+          algoRequiringCleaning = curAlgo;
     }
   }
 
@@ -663,7 +759,7 @@ SMESH_Hypothesis::Hypothesis_Status
     if ( ! CanAddHypothesis( anHyp )) // check dimension
       return SMESH_Hypothesis::HYP_BAD_DIM;
 
-    if ( /*!anHyp->IsAuxiliary() &&*/ getSimilarAttached( _subShape, anHyp ) )
+    if ( !anHyp->IsAuxiliary() && getSimilarAttached( _subShape, anHyp ) )
       return SMESH_Hypothesis::HYP_ALREADY_EXIST;
 
     if ( !meshDS->AddHypothesis(_subShape, anHyp))
@@ -682,12 +778,7 @@ SMESH_Hypothesis::Hypothesis_Status
     {
       algo = dynamic_cast<SMESH_Algo*> (anHyp);
       if (!algo->NeedDiscreteBoundary())
-      {
-        // clean all mesh in the tree of the current submesh;
-        // we must perform it now because later
-        // we will have no information about the type of the removed algo
-        needFullClean = true;
-      }
+        algoRequiringCleaning = algo;
     }
   }
 
@@ -697,6 +788,9 @@ SMESH_Hypothesis::Hypothesis_Status
   if (!isApplicableHyp)
     return ret; // not applicable hypotheses do not change algo state
 
+  if (( algo = GetAlgo()))
+    algo->InitComputeError();
+
   switch (_algoState)
   {
 
@@ -861,7 +955,7 @@ SMESH_Hypothesis::Hypothesis_Status
           // ret should be fatal: anHyp was not added
           ret = SMESH_Hypothesis::HYP_INCOMPATIBLE;
       }
-      else if (!_father->IsUsedHypothesis(  anHyp, this ))
+      else if (!_father->IsUsedHypothesis( anHyp, this ))
         ret = SMESH_Hypothesis::HYP_INCOMPATIBLE;
 
       if (SMESH_Hypothesis::IsStatusFatal( ret ))
@@ -883,7 +977,7 @@ SMESH_Hypothesis::Hypothesis_Status
         f.Init(   SMESH_HypoFilter::IsAlgo() );
         f.And(    SMESH_HypoFilter::IsApplicableTo( _subShape ));
         f.AndNot( SMESH_HypoFilter::Is( algo ));
-        const SMESH_Hypothesis * prevAlgo = _father->GetHypothesis( _subShape, f, true );
+        const SMESH_Hypothesis * prevAlgo = _father->GetHypothesis( this, f, true );
         if (prevAlgo &&
             string(algo->GetName()) != string(prevAlgo->GetName()) )
           modifiedHyp = true;
@@ -942,7 +1036,7 @@ SMESH_Hypothesis::Hypothesis_Status
           f.Init(   SMESH_HypoFilter::IsAlgo() );
           f.And(    SMESH_HypoFilter::IsApplicableTo( _subShape ));
           f.AndNot( SMESH_HypoFilter::Is( algo ));
-          const SMESH_Hypothesis* prevAlgo = _father->GetHypothesis( _subShape, f, true );
+          const SMESH_Hypothesis* prevAlgo = _father->GetHypothesis( this, f, true );
           if (prevAlgo &&
               string(algo->GetName()) != string(prevAlgo->GetName()) )
             modifiedHyp = true;
@@ -969,8 +1063,7 @@ SMESH_Hypothesis::Hypothesis_Status
       // CLEAN was not called at event REMOVE_ALGO because the algo is not applicable to SOLID.
       algo = dynamic_cast<SMESH_Algo*> (anHyp);
       if (!algo->NeedDiscreteBoundary())
-        needFullClean = true;
-
+        algoRequiringCleaning = algo;
       algo = GetAlgo();
       if (algo == NULL)  // no more applying algo on father
       {
@@ -1009,31 +1102,40 @@ SMESH_Hypothesis::Hypothesis_Status
   {
     // is algo hidden?
     SMESH_Gen* gen = _father->GetGen();
-    TopTools_ListIteratorOfListOfShape it( _father->GetAncestors( _subShape ));
-    for ( ; ( ret == SMESH_Hypothesis::HYP_OK && it.More()); it.Next() ) {
-      if ( SMESH_Algo* upperAlgo = gen->GetAlgo( *_father, it.Value() ))
+    const std::vector< SMESH_subMesh * > & ancestors = GetAncestors();
+    for ( size_t iA = 0; ( ret == SMESH_Hypothesis::HYP_OK && iA < ancestors.size()); ++iA ) {
+      if ( SMESH_Algo* upperAlgo = ancestors[ iA ]->GetAlgo() )
         if ( !upperAlgo->NeedDiscreteBoundary() && !upperAlgo->SupportSubmeshes())
           ret = SMESH_Hypothesis::HYP_HIDDEN_ALGO;
     }
     // is algo hiding?
     if ( ret == SMESH_Hypothesis::HYP_OK &&
          !algo->NeedDiscreteBoundary()    &&
-         !algo->SupportSubmeshes()) {
+         !algo->SupportSubmeshes())
+    {
       TopoDS_Shape algoAssignedTo, otherAssignedTo;
-      gen->GetAlgo( *_father, _subShape, &algoAssignedTo );
+      gen->GetAlgo( this, &algoAssignedTo );
       map<int, SMESH_subMesh*>::reverse_iterator i_sm = _mapDepend.rbegin();
       for ( ; ( ret == SMESH_Hypothesis::HYP_OK && i_sm != _mapDepend.rend()) ; ++i_sm )
-        if ( gen->GetAlgo( *_father, i_sm->second->_subShape, &otherAssignedTo ) &&
+        if ( gen->GetAlgo( i_sm->second, &otherAssignedTo ) &&
              SMESH_MesherHelper::IsSubShape( /*sub=*/otherAssignedTo, /*main=*/algoAssignedTo ))
           ret = SMESH_Hypothesis::HYP_HIDING_ALGO;
     }
   }
 
+  if ( _algo ) { // get an error description set by _algo->CheckHypothesis()
+    _computeError = _algo->GetComputeError();
+    _algo->InitComputeError();
+  }
+
   bool stateChange = ( _algoState != oldAlgoState );
 
   if ( stateChange && _algoState == HYP_OK ) // hyp becomes OK
     algo->SetEventListener( this );
 
+  if ( event == REMOVE_ALGO || event == REMOVE_FATHER_ALGO )
+    _algo = 0;
+
   notifyListenersOnEvent( event, ALGO_EVENT, anHyp );
 
   if ( stateChange && oldAlgoState == HYP_OK ) { // hyp becomes KO
@@ -1046,15 +1148,17 @@ SMESH_Hypothesis::Hypothesis_Status
     }
   }
 
-  if ( needFullClean ) {
+  if ( algoRequiringCleaning ) {
     // added or removed algo is all-dimensional
     ComputeStateEngine( CLEAN );
-    cleanDependsOn();
+    cleanDependsOn( algoRequiringCleaning );
     ComputeSubMeshStateEngine( CHECK_COMPUTE_STATE );
   }
 
-  if (stateChange || modifiedHyp)
-    ComputeStateEngine(MODIF_ALGO_STATE);
+  if ( stateChange || modifiedHyp )
+    ComputeStateEngine( MODIF_ALGO_STATE );
+
+  _realComputeCost = ( _algoState == HYP_OK ) ? computeCost() : 0;
 
   return ret;
 }
@@ -1092,16 +1196,16 @@ bool SMESH_subMesh::IsConform(const SMESH_Algo* theAlgo)
   for (; itsub.More(); itsub.Next())
   {
     // loop on adjacent subShapes
-    TopTools_ListIteratorOfListOfShape it( _father->GetAncestors( itsub.Value() ));
-    for (; it.More(); it.Next())
+    const std::vector< SMESH_subMesh * > & ancestors = GetAncestors();
+    for ( size_t iA = 0; iA < ancestors.size(); ++iA )
     {
-      const TopoDS_Shape& adjacent = it.Value();
+      const TopoDS_Shape& adjacent = ancestors[ iA ]->GetSubShape();
       if ( _subShape.IsSame( adjacent )) continue;
       if ( adjacent.ShapeType() != _subShape.ShapeType())
         break;
 
       // check algo attached to smAdjacent
-      SMESH_Algo * algo = gen->GetAlgo((*_father), adjacent);
+      SMESH_Algo * algo = ancestors[ iA ]->GetAlgo();
       if (algo &&
           !algo->NeedDiscreteBoundary() &&
           algo->OnlyUnaryInput())
@@ -1118,19 +1222,29 @@ bool SMESH_subMesh::IsConform(const SMESH_Algo* theAlgo)
  */
 //=============================================================================
 
-void SMESH_subMesh::setAlgoState(int state)
+void SMESH_subMesh::setAlgoState(algo_state state)
 {
   _algoState = state;
 }
 
-//=============================================================================
+//================================================================================
 /*!
+ * \brief Send an event to sub-meshes
+ *  \param [in] event - the event
+ *  \param [in] anHyp - an hypothesis
+ *  \param [in] exitOnFatal - to stop iteration on sub-meshes if a sub-mesh
+ *              reports a fatal result
+ *  \return SMESH_Hypothesis::Hypothesis_Status - the worst result
  *
+ * Optional description of a problematic situation (if any) can be retrieved
+ * via GetComputeError().
  */
-//=============================================================================
+//================================================================================
+
 SMESH_Hypothesis::Hypothesis_Status
-  SMESH_subMesh::SubMeshesAlgoStateEngine(int event,
-                                          SMESH_Hypothesis * anHyp)
+  SMESH_subMesh::SubMeshesAlgoStateEngine(int                event,
+                                          SMESH_Hypothesis * anHyp,
+                                          bool               exitOnFatal)
 {
   SMESH_Hypothesis::Hypothesis_Status ret = SMESH_Hypothesis::HYP_OK;
   //EAP: a wire (dim==1) should notify edges (dim==1)
@@ -1139,26 +1253,96 @@ SMESH_Hypothesis::Hypothesis_Status
   {
     SMESH_subMeshIteratorPtr smIt = getDependsOnIterator(false,false);
     while ( smIt->more() ) {
-      SMESH_Hypothesis::Hypothesis_Status ret2 =
-        smIt->next()->AlgoStateEngine(event, anHyp);
+      SMESH_subMesh* sm = smIt->next();
+      SMESH_Hypothesis::Hypothesis_Status ret2 = sm->AlgoStateEngine(event, anHyp);
       if ( ret2 > ret )
+      {
         ret = ret2;
+        _computeError = sm->_computeError;
+        sm->_computeError.reset();
+        if ( exitOnFatal && SMESH_Hypothesis::IsStatusFatal( ret ))
+          break;
+      }
     }
   }
   return ret;
 }
 
-//=============================================================================
+//================================================================================
 /*!
- *
+ * \brief Remove elements from sub-meshes.
+ *  \param algoRequiringCleaning - an all-dimensional algorithm whose presence
+ *         causes the cleaning.
  */
-//=============================================================================
+//================================================================================
 
-void SMESH_subMesh::cleanDependsOn()
+void SMESH_subMesh::cleanDependsOn( SMESH_Algo* algoRequiringCleaning/*=0*/ )
 {
-  SMESH_subMeshIteratorPtr smIt = getDependsOnIterator(false,false);
-  while ( smIt->more() )
-    smIt->next()->ComputeStateEngine(CLEAN);
+  SMESH_subMeshIteratorPtr smIt = getDependsOnIterator(false,
+                                                       /*complexShapeFirst=*/true);
+  if ( _father->NbNodes() == 0 )
+  {
+    while ( smIt->more() )
+      smIt->next()->ComputeStateEngine(CHECK_COMPUTE_STATE);
+  }
+  else if ( !algoRequiringCleaning || !algoRequiringCleaning->SupportSubmeshes() )
+  {
+    while ( smIt->more() )
+      smIt->next()->ComputeStateEngine(CLEAN);
+  }
+  else if ( algoRequiringCleaning && algoRequiringCleaning->SupportSubmeshes() )
+  {
+    SMESHDS_Mesh* meshDS = _father->GetMeshDS();
+
+    // find sub-meshes to keep elements on
+    set< SMESH_subMesh* > smToKeep;
+    TopAbs_ShapeEnum prevShapeType = TopAbs_SHAPE;
+    bool toKeepPrevShapeType = false;
+    while ( smIt->more() )
+    {
+      SMESH_subMesh* sm = smIt->next();
+      sm->ComputeStateEngine(CHECK_COMPUTE_STATE);
+      if ( !sm->IsEmpty() )
+      {
+        const bool sameShapeType = ( prevShapeType == sm->GetSubShape().ShapeType() );
+        bool keepSubMeshes = ( sameShapeType && toKeepPrevShapeType );
+        if ( !sameShapeType )
+        {
+          // check if the algo allows presence of global algos of dimension the algo
+          // can generate it-self
+          int  shapeDim = SMESH_Gen::GetShapeDim( sm->GetSubShape() );
+          keepSubMeshes = algoRequiringCleaning->NeedLowerHyps( shapeDim );
+          prevShapeType = sm->GetSubShape().ShapeType();
+          toKeepPrevShapeType = keepSubMeshes;
+        }
+        if ( !keepSubMeshes )
+        {
+          // look for an algo assigned to sm
+          bool algoFound = false;
+          const list<const SMESHDS_Hypothesis*>& hyps = meshDS->GetHypothesis( sm->_subShape );
+          list<const SMESHDS_Hypothesis*>::const_iterator h = hyps.begin();
+          for ( ; ( !algoFound && h != hyps.end() ); ++h )
+            algoFound = ((*h)->GetType() != SMESHDS_Hypothesis::PARAM_ALGO );
+          keepSubMeshes = algoFound;
+        }
+        // remember all sub-meshes of sm
+        if ( keepSubMeshes )
+        {
+          SMESH_subMeshIteratorPtr smIt2 = getDependsOnIterator(false,true);
+          while ( smIt2->more() )
+            smToKeep.insert( smIt2->next() );
+        }
+      }
+    }
+    // remove elements
+    SMESH_subMeshIteratorPtr smIt = getDependsOnIterator(false,true);
+    while ( smIt->more() )
+    {
+      SMESH_subMesh* sm = smIt->next();
+      if ( !smToKeep.count( sm ))
+        sm->ComputeStateEngine(CLEAN);
+    }
+  }
 }
 
 //=============================================================================
@@ -1169,8 +1353,7 @@ void SMESH_subMesh::cleanDependsOn()
 
 void SMESH_subMesh::DumpAlgoState(bool isMain)
 {
-        int dim = SMESH_Gen::GetShapeDim(_subShape);
-//   if (dim < 1) return;
+  // if (dim < 1) return;
         if (isMain)
         {
                 const map < int, SMESH_subMesh * >&subMeshes = DependsOn();
@@ -1182,8 +1365,9 @@ void SMESH_subMesh::DumpAlgoState(bool isMain)
                         sm->DumpAlgoState(false);
                 }
         }
-        int type = _subShape.ShapeType();
-        MESSAGE("dim = " << dim << " type of shape " << type);
+        //int type = _subShape.ShapeType();
+        MESSAGE("dim = " << SMESH_Gen::GetShapeDim(_subShape) <<
+                " type of shape " << _subShape.ShapeType());
         switch (_algoState)
         {
         case NO_ALGO:
@@ -1230,7 +1414,7 @@ static void cleanSubMesh( SMESH_subMesh * subMesh )
         const SMDS_MeshElement * elt = ite->next();
         //MESSAGE( " RM elt: "<<elt->GetID()<<" ( "<<elt->NbNodes()<<" )" );
         //meshDS->RemoveElement(elt);
-        meshDS->RemoveFreeElement(elt, subMeshDS);
+        meshDS->RemoveFreeElement(elt, 0);
       }
 
       SMDS_NodeIteratorPtr itn = subMeshDS->GetNodes();
@@ -1238,10 +1422,11 @@ static void cleanSubMesh( SMESH_subMesh * subMesh )
         const SMDS_MeshNode * node = itn->next();
         //MESSAGE( " RM node: "<<node->GetID());
         if ( node->NbInverseElements() == 0 )
-          meshDS->RemoveFreeNode(node, subMeshDS);
+          meshDS->RemoveFreeNode(node, 0);
         else // for StdMeshers_CompositeSegment_1D: node in one submesh, edge in another
           meshDS->RemoveNode(node);
       }
+      subMeshDS->Clear();
     }
   }
 }
@@ -1254,17 +1439,30 @@ static void cleanSubMesh( SMESH_subMesh * subMesh )
 
 bool SMESH_subMesh::ComputeStateEngine(int event)
 {
-  _computeError.reset();
+  switch ( event ) {
+  case MODIF_ALGO_STATE:
+  case COMPUTE:
+  case COMPUTE_SUBMESH:
+    //case COMPUTE_CANCELED:
+  case CLEAN:
+    //case SUBMESH_COMPUTED:
+    //case SUBMESH_RESTORED:
+    //case SUBMESH_LOADED:
+    //case MESH_ENTITY_REMOVED:
+    //case CHECK_COMPUTE_STATE:
+    _computeError.reset(); break;
+  default:;
+  }
 
-  //MESSAGE("SMESH_subMesh::ComputeStateEngine");
-  //SCRUTE(_computeState);
-  //SCRUTE(event);
+  if ( event == CLEAN )
+    _alwaysComputed = false; // Unset 'true' set by MergeNodes() (issue 0022182)
 
   if (_subShape.ShapeType() == TopAbs_VERTEX)
   {
     _computeState = READY_TO_COMPUTE;
     SMESHDS_SubMesh* smDS = GetSubMeshDS();
-    if ( smDS && smDS->NbNodes() ) {
+    if ( smDS && smDS->NbNodes() )
+    {
       if ( event == CLEAN ) {
         cleanDependants();
         cleanSubMesh( this );
@@ -1272,7 +1470,9 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
       else
         _computeState = COMPUTE_OK;
     }
-    else if ( event == COMPUTE && !_alwaysComputed ) {
+    else if (( event == COMPUTE || event == COMPUTE_SUBMESH )
+             && !_alwaysComputed )
+    {
       const TopoDS_Vertex & V = TopoDS::Vertex( _subShape );
       gp_Pnt P = BRep_Tool::Pnt(V);
       if ( SMDS_MeshNode * n = _father->GetMeshDS()->AddNode(P.X(), P.Y(), P.Z()) ) {
@@ -1301,16 +1501,15 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
     case MODIF_ALGO_STATE:
       algo = GetAlgo();
       if (algo && !algo->NeedDiscreteBoundary())
-        cleanDependsOn(); // clean sub-meshes with event CLEAN
+        cleanDependsOn( algo ); // clean sub-meshes with event CLEAN
       if ( _algoState == HYP_OK )
         _computeState = READY_TO_COMPUTE;
       break;
     case COMPUTE:               // nothing to do
+    case COMPUTE_SUBMESH:
       break;
-#ifdef WITH_SMESH_CANCEL_COMPUTE
-    case COMPUTE_CANCELED:               // nothing to do
+    case COMPUTE_CANCELED:      // nothing to do
       break;
-#endif
     case CLEAN:
       cleanDependants();
       removeSubMeshElementsAndNodes();
@@ -1347,12 +1546,13 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
       if (algo)
       {
         if (!algo->NeedDiscreteBoundary())
-          cleanDependsOn(); // clean sub-meshes with event CLEAN
+          cleanDependsOn( algo ); // clean sub-meshes with event CLEAN
         if ( _algoState == HYP_OK )
           _computeState = READY_TO_COMPUTE;
       }
       break;
     case COMPUTE:
+    case COMPUTE_SUBMESH:
       {
         algo = GetAlgo();
         ASSERT(algo);
@@ -1365,27 +1565,38 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
           break;
         }
         TopoDS_Shape shape = _subShape;
+        algo->SubMeshesToCompute().assign( 1, this );
         // check submeshes needed
         if (_father->HasShapeToMesh() ) {
-          bool subComputed = false;
-          if (!algo->OnlyUnaryInput())
-            shape = getCollection( gen, algo, subComputed );
-          else
-            subComputed = subMeshesComputed();
+          bool subComputed = false, subFailed = false;
+          if (!algo->OnlyUnaryInput()) {
+            if ( event == COMPUTE /*&&
+                 ( algo->NeedDiscreteBoundary() || algo->SupportSubmeshes() )*/)
+              shape = getCollection( gen, algo, subComputed, subFailed, algo->SubMeshesToCompute());
+            else
+              subComputed = SubMeshesComputed( & subFailed );
+          }
+          else {
+            subComputed = SubMeshesComputed();
+          }
           ret = ( algo->NeedDiscreteBoundary() ? subComputed :
-                  algo->SupportSubmeshes() ? true :
+                  algo->SupportSubmeshes() ? !subFailed :
                   ( !subComputed || _father->IsNotConformAllowed() ));
-          if (!ret) {
+          if (!ret)
+          {
             _computeState = FAILED_TO_COMPUTE;
-            if ( !algo->NeedDiscreteBoundary() )
+            if ( !algo->NeedDiscreteBoundary() && !subFailed )
               _computeError =
                 SMESH_ComputeError::New(COMPERR_BAD_INPUT_MESH,
-                                        "Unexpected computed submesh",algo);
-            break;
+                                        "Unexpected computed sub-mesh",algo);
+            break; // goto exit
           }
         }
         // Compute
 
+        // to restore cout that may be redirected by algo
+        std::streambuf* coutBuffer = std::cout.rdbuf();
+
         //cleanDependants(); for "UseExisting_*D" algos
         //removeSubMeshElementsAndNodes();
         loadDependentMeshes();
@@ -1393,10 +1604,10 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
         _computeState = FAILED_TO_COMPUTE;
         _computeError = SMESH_ComputeError::New(COMPERR_OK,"",algo);
         try {
-#if OCC_VERSION_LARGE > 0x06010000
           OCC_CATCH_SIGNALS;
-#endif
+
           algo->InitComputeError();
+
           MemoryReserve aMemoryReserve;
           SMDS_Mesh::CheckMemory();
           Kernel_Utils::Localizer loc;
@@ -1411,8 +1622,8 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
           {
             ret = algo->Compute((*_father), shape);
           }
-          if ( !_computeError || ( !ret && _computeError->IsOK() ) ) // algo can set _computeError of submesh
-            _computeError = algo->GetComputeError();
+          // algo can set _computeError of submesh
+          _computeError = SMESH_ComputeError::Worst( _computeError, algo->GetComputeError() );
         }
         catch ( ::SMESH_ComputeError& comperr ) {
           cout << " SMESH_ComputeError caught" << endl;
@@ -1447,9 +1658,12 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
           }
         }
         catch ( SALOME_Exception& S_ex ) {
+          const int skipSalomeShift = 7; /* to skip "Salome " of
+                                            "Salome Exception" prefix returned
+                                            by SALOME_Exception::what() */
           if ( !_computeError ) _computeError = SMESH_ComputeError::New();
           _computeError->myName    = COMPERR_SLM_EXCEPTION;
-          _computeError->myComment = S_ex.what();
+          _computeError->myComment = S_ex.what() + skipSalomeShift;
         }
         catch ( std::exception& exc ) {
           if ( !_computeError ) _computeError = SMESH_ComputeError::New();
@@ -1462,16 +1676,25 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
           else
             ret = false;
         }
+        std::cout.rdbuf( coutBuffer ); // restore cout that could be redirected by algo
+
+        // check if an error reported on any sub-shape
+        bool isComputeErrorSet = !checkComputeError( algo, ret, shape );
+        if ( isComputeErrorSet )
+          ret = false;
+        // check if anything was built
         TopExp_Explorer subS(shape, _subShape.ShapeType());
-        if (ret) // check if anything was built
+        if (ret)
         {
           for (; ret && subS.More(); subS.Next())
-            ret = _father->GetSubMesh( subS.Current() )->IsMeshComputed();
+            if ( !_father->GetSubMesh( subS.Current() )->IsMeshComputed() &&
+                 ( _subShape.ShapeType() != TopAbs_EDGE ||
+                   !algo->isDegenerated( TopoDS::Edge( subS.Current() ))))
+              ret = false;
         }
-        bool isComputeErrorSet = !checkComputeError( algo, shape );
+        // Set _computeError
         if (!ret && !isComputeErrorSet)
         {
-          // Set _computeError
           for (subS.ReInit(); subS.More(); subS.Next())
           {
             SMESH_subMesh* sm = _father->GetSubMesh( subS.Current() );
@@ -1490,13 +1713,30 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
         {
           _computeError.reset();
         }
-        updateDependantsState( SUBMESH_COMPUTED ); // send event SUBMESH_COMPUTED
+
+        // send event SUBMESH_COMPUTED
+        if ( ret ) {
+          if ( !algo->NeedDiscreteBoundary() )
+            // send SUBMESH_COMPUTED to dependants of all sub-meshes of shape
+            for (subS.ReInit(); subS.More(); subS.Next())
+            {
+              SMESH_subMesh* sm = _father->GetSubMesh( subS.Current() );
+              SMESH_subMeshIteratorPtr smIt = sm->getDependsOnIterator(false,false);
+              while ( smIt->more() ) {
+                sm = smIt->next();
+                if ( sm->GetSubShape().ShapeType() == TopAbs_VERTEX )
+                  sm->updateDependantsState( SUBMESH_COMPUTED );
+                else
+                  break;
+              }
+            }
+          else
+            updateDependantsState( SUBMESH_COMPUTED );
+        }
       }
       break;
-#ifdef WITH_SMESH_CANCEL_COMPUTE
     case COMPUTE_CANCELED:               // nothing to do
       break;
-#endif
     case CLEAN:
       cleanDependants();
       removeSubMeshElementsAndNodes();
@@ -1530,6 +1770,8 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
     case CHECK_COMPUTE_STATE:
       if ( IsMeshComputed() )
         _computeState = COMPUTE_OK;
+      else if ( _computeError && _computeError->IsKO() )
+        _computeState = FAILED_TO_COMPUTE;
       break;
     default:
       ASSERT(0);
@@ -1546,14 +1788,12 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
       ComputeStateEngine( CLEAN );
       algo = GetAlgo();
       if (algo && !algo->NeedDiscreteBoundary())
-        cleanDependsOn(); // clean sub-meshes with event CLEAN
+        cleanDependsOn( algo ); // clean sub-meshes with event CLEAN
       break;
     case COMPUTE:               // nothing to do
       break;
-#ifdef WITH_SMESH_CANCEL_COMPUTE
-    case COMPUTE_CANCELED:               // nothing to do
+    case COMPUTE_CANCELED:      // nothing to do
       break;
-#endif
     case CLEAN:
       cleanDependants();  // clean sub-meshes, dependant on this one, with event CLEAN
       removeSubMeshElementsAndNodes();
@@ -1601,13 +1841,14 @@ bool SMESH_subMesh::ComputeStateEngine(int event)
         ComputeStateEngine( CLEAN );
       algo = GetAlgo();
       if (algo && !algo->NeedDiscreteBoundary())
-        cleanDependsOn(); // clean sub-meshes with event CLEAN
+        cleanDependsOn( algo ); // clean sub-meshes with event CLEAN
       if (_algoState == HYP_OK)
         _computeState = READY_TO_COMPUTE;
       else
         _computeState = NOT_READY;
       break;
-    case COMPUTE:      // nothing to do
+    case COMPUTE:        // nothing to do
+    case COMPUTE_SUBMESH:
       break;
     case COMPUTE_CANCELED:
       {
@@ -1723,7 +1964,9 @@ bool SMESH_subMesh::Evaluate(MapShapeNbElems& aResMap)
  */
 //=======================================================================
 
-bool SMESH_subMesh::checkComputeError(SMESH_Algo* theAlgo, const TopoDS_Shape& theShape)
+bool SMESH_subMesh::checkComputeError(SMESH_Algo*         theAlgo,
+                                      const bool          theComputeOK,
+                                      const TopoDS_Shape& theShape)
 {
   bool noErrors = true;
 
@@ -1734,7 +1977,7 @@ bool SMESH_subMesh::checkComputeError(SMESH_Algo* theAlgo, const TopoDS_Shape& t
     {
       SMESH_subMeshIteratorPtr smIt = getDependsOnIterator(false,false);
       while ( smIt->more() )
-        if ( !smIt->next()->checkComputeError( theAlgo ))
+        if ( !smIt->next()->checkComputeError( theAlgo, theComputeOK ))
           noErrors = false;
     }
 
@@ -1746,7 +1989,7 @@ bool SMESH_subMesh::checkComputeError(SMESH_Algo* theAlgo, const TopoDS_Shape& t
       for (TopoDS_Iterator subIt( theShape ); subIt.More(); subIt.Next()) {
         SMESH_subMesh* sm = _father->GetSubMesh( subIt.Value() );
         if ( sm != this ) {
-          if ( !sm->checkComputeError( theAlgo, sm->GetSubShape() ))
+          if ( !sm->checkComputeError( theAlgo, theComputeOK, sm->GetSubShape() ))
             noErrors = false;
           updateDependantsState( SUBMESH_COMPUTED ); // send event SUBMESH_COMPUTED
         }
@@ -1754,13 +1997,24 @@ bool SMESH_subMesh::checkComputeError(SMESH_Algo* theAlgo, const TopoDS_Shape& t
     }
   }
   {
-    // Check my state
+
+    // Set my _computeState
+
     if ( !_computeError || _computeError->IsOK() )
     {
       // no error description is set to this sub-mesh, check if any mesh is computed
       _computeState = IsMeshComputed() ? COMPUTE_OK : FAILED_TO_COMPUTE;
+      if ( _computeState != COMPUTE_OK )
+      {
+        if ( _subShape.ShapeType() == TopAbs_EDGE &&
+             SMESH_Algo::isDegenerated( TopoDS::Edge( _subShape )) )
+          _computeState = COMPUTE_OK;
+        else if ( theComputeOK )
+          _computeError = SMESH_ComputeError::New(COMPERR_NO_MESH_ON_SHAPE,"",theAlgo);
+      }
     }
-    else
+
+    if ( _computeError && !_computeError->IsOK() )
     {
       if ( !_computeError->myAlgo )
         _computeError->myAlgo = theAlgo;
@@ -1816,14 +2070,10 @@ void SMESH_subMesh::ComputeSubMeshStateEngine(int event, const bool includeSelf)
 
 void SMESH_subMesh::updateDependantsState(const compute_event theEvent)
 {
-  TopTools_ListIteratorOfListOfShape it( _father->GetAncestors( _subShape ));
-  for (; it.More(); it.Next())
+  const std::vector< SMESH_subMesh * > & ancestors = GetAncestors();
+  for ( size_t iA = 0; iA < ancestors.size(); ++iA )
   {
-    const TopoDS_Shape& ancestor = it.Value();
-    SMESH_subMesh *aSubMesh =
-      _father->GetSubMeshContaining(ancestor);
-    if (aSubMesh)
-      aSubMesh->ComputeStateEngine( theEvent );
+    ancestors[ iA ]->ComputeStateEngine( theEvent );
   }
 }
 
@@ -1837,19 +2087,17 @@ void SMESH_subMesh::cleanDependants()
 {
   int dimToClean = SMESH_Gen::GetShapeDim( _subShape ) + 1;
 
-  TopTools_ListIteratorOfListOfShape it( _father->GetAncestors( _subShape ));
-  for (; it.More(); it.Next())
+  const std::vector< SMESH_subMesh * > & ancestors = GetAncestors();
+  for ( size_t iA = 0; iA < ancestors.size(); ++iA )
   {
-    const TopoDS_Shape& ancestor = it.Value();
-    if ( SMESH_Gen::GetShapeDim( ancestor ) == dimToClean ) {
+    const TopoDS_Shape& ancestor = ancestors[ iA ]->GetSubShape();
+    if ( SMESH_Gen::GetShapeDim( ancestor ) == dimToClean )
+    {
       // PAL8021. do not go upper than SOLID, else ComputeStateEngine(CLEAN)
       // will erase mesh on other shapes in a compound
-      if ( ancestor.ShapeType() >= TopAbs_SOLID ) {
-        SMESH_subMesh *aSubMesh = _father->GetSubMeshContaining(ancestor);
-        if (aSubMesh &&
-            !aSubMesh->IsEmpty() ) // prevent infinite CLEAN via event lesteners
-          aSubMesh->ComputeStateEngine(CLEAN);
-      }
+      if ( ancestor.ShapeType() >= TopAbs_SOLID &&
+           !ancestors[ iA ]->IsEmpty() )  // prevent infinite CLEAN via event lesteners
+        ancestors[ iA ]->ComputeStateEngine(CLEAN);
     }
   }
 }
@@ -1889,43 +2137,52 @@ void SMESH_subMesh::removeSubMeshElementsAndNodes()
 
 TopoDS_Shape SMESH_subMesh::getCollection(SMESH_Gen * theGen,
                                           SMESH_Algo* theAlgo,
-                                          bool &      theSubComputed)
+                                          bool &      theSubComputed,
+                                          bool &      theSubFailed,
+                                          std::vector<SMESH_subMesh*>& theSubs)
 {
-  theSubComputed = subMeshesComputed();
+  theSubComputed = SubMeshesComputed( & theSubFailed );
 
   TopoDS_Shape mainShape = _father->GetMeshDS()->ShapeToMesh();
 
   if ( mainShape.IsSame( _subShape ))
     return _subShape;
 
-  const bool ignoreAuxiliaryHyps = false;
+  const bool skipAuxHyps = false;
   list<const SMESHDS_Hypothesis*> aUsedHyp =
-    theAlgo->GetUsedHypothesis( *_father, _subShape, ignoreAuxiliaryHyps ); // copy
+    theAlgo->GetUsedHypothesis( *_father, _subShape, skipAuxHyps ); // copy
 
   // put in a compound all shapes with the same hypothesis assigned
-  // and a good ComputState
+  // and a good ComputeState
 
   TopoDS_Compound aCompound;
   BRep_Builder aBuilder;
   aBuilder.MakeCompound( aCompound );
 
-  TopExp_Explorer anExplorer( mainShape, _subShape.ShapeType() );
-  for ( ; anExplorer.More(); anExplorer.Next() )
+  theSubs.clear();
+
+  SMESH_subMeshIteratorPtr smIt = _father->GetSubMesh( mainShape )->getDependsOnIterator(false);
+  while ( smIt->more() )
   {
-    const TopoDS_Shape& S = anExplorer.Current();
-    SMESH_subMesh* subMesh = _father->GetSubMesh( S );
+    SMESH_subMesh* subMesh = smIt->next();
+    const TopoDS_Shape&  S = subMesh->_subShape;
+    if ( S.ShapeType() != this->_subShape.ShapeType() )
+      continue;
+    theSubs.push_back( subMesh );
     if ( subMesh == this )
     {
       aBuilder.Add( aCompound, S );
     }
     else if ( subMesh->GetComputeState() == READY_TO_COMPUTE )
     {
-      SMESH_Algo* anAlgo = theGen->GetAlgo( *_father, S );
-      if (strcmp( anAlgo->GetName(), theAlgo->GetName()) == 0 && // same algo
-          anAlgo->GetUsedHypothesis( *_father, S, ignoreAuxiliaryHyps ) == aUsedHyp) // same hyps
+      SMESH_Algo* anAlgo = subMesh->GetAlgo();
+      if (( anAlgo->IsSameName( *theAlgo )) && // same algo
+          ( anAlgo->GetUsedHypothesis( *_father, S, skipAuxHyps ) == aUsedHyp )) // same hyps
+      {
         aBuilder.Add( aCompound, S );
-      if ( !subMesh->subMeshesComputed() )
-        theSubComputed = false;
+        if ( !subMesh->SubMeshesComputed() )
+          theSubComputed = false;
+      }
     }
   }
 
@@ -2047,7 +2304,8 @@ void SMESH_subMesh::SetEventListener(EventListener*     listener,
  */
 //================================================================================
 
-void SMESH_subMesh::setEventListener(EventListener* listener, EventListenerData* data)
+void SMESH_subMesh::setEventListener(EventListener*     listener,
+                                     EventListenerData* data)
 {
   map< EventListener*, EventListenerData* >::iterator l_d =
     _eventListeners.find( listener );
@@ -2057,24 +2315,84 @@ void SMESH_subMesh::setEventListener(EventListener* listener, EventListenerData*
       delete curData;
     l_d->second = data;
   }
-  else 
+  else
+  {
+    for ( l_d = _eventListeners.begin(); l_d != _eventListeners.end(); ++l_d )
+      if ( listener->GetName() == l_d->first->GetName() )
+      {
+        EventListenerData* curData = l_d->second;
+        if ( curData && curData != data && curData->IsDeletable() )
+          delete curData;
+        if ( l_d->first != listener && l_d->first->IsDeletable() )
+          delete l_d->first;
+        _eventListeners.erase( l_d );
+        break;
+      }
     _eventListeners.insert( make_pair( listener, data ));
+  }
 }
 
 //================================================================================
 /*!
  * \brief Return an event listener data
  * \param listener - the listener whose data is
+ * \param myOwn - if \c true, returns a listener set by this sub-mesh,
+ *        else returns a listener listening to events of this sub-mesh
  * \retval EventListenerData* - found data, maybe NULL
  */
 //================================================================================
 
-EventListenerData* SMESH_subMesh::GetEventListenerData(EventListener* listener) const
+EventListenerData* SMESH_subMesh::GetEventListenerData(EventListener* listener,
+                                                       const bool     myOwn) const
 {
-  map< EventListener*, EventListenerData* >::const_iterator l_d =
-    _eventListeners.find( listener );
-  if ( l_d != _eventListeners.end() )
-    return l_d->second;
+  if ( myOwn )
+  {
+    list< OwnListenerData >::const_iterator d;
+    for ( d = _ownListeners.begin(); d != _ownListeners.end(); ++d )
+    {
+      if ( d->myListener == listener && _father->MeshExists( d->myMeshID ))
+        return d->mySubMesh->GetEventListenerData( listener, !myOwn );
+    }
+  }
+  else
+  {
+    map< EventListener*, EventListenerData* >::const_iterator l_d =
+      _eventListeners.find( listener );
+    if ( l_d != _eventListeners.end() )
+      return l_d->second;
+  }
+  return 0;
+}
+
+//================================================================================
+/*!
+ * \brief Return an event listener data
+ * \param listenerName - the listener name
+ * \param myOwn - if \c true, returns a listener set by this sub-mesh,
+ *        else returns a listener listening to events of this sub-mesh
+ * \retval EventListenerData* - found data, maybe NULL
+ */
+//================================================================================
+
+EventListenerData* SMESH_subMesh::GetEventListenerData(const string& listenerName,
+                                                       const bool    myOwn) const
+{
+  if ( myOwn )
+  {
+    list< OwnListenerData >::const_iterator d;
+    for ( d = _ownListeners.begin(); d != _ownListeners.end(); ++d )
+    {
+      if ( _father->MeshExists( d->myMeshID ) && listenerName == d->myListener->GetName())
+        return d->mySubMesh->GetEventListenerData( listenerName, !myOwn );
+    }
+  }
+  else
+  {
+    map< EventListener*, EventListenerData* >::const_iterator l_d = _eventListeners.begin();
+    for ( ; l_d != _eventListeners.end(); ++l_d )
+      if ( listenerName == l_d->first->GetName() )
+        return l_d->second;
+  }
   return 0;
 }
 
@@ -2091,17 +2409,22 @@ void SMESH_subMesh::notifyListenersOnEvent( const int         event,
                                             const event_type  eventType,
                                             SMESH_Hypothesis* hyp)
 {
-  map< EventListener*, EventListenerData* >::iterator l_d = _eventListeners.begin();
-  for ( ; l_d != _eventListeners.end(); ++l_d )
+  list< pair< EventListener*, EventListenerData* > > eventListeners( _eventListeners.begin(),
+                                                                     _eventListeners.end());
+  list< pair< EventListener*, EventListenerData* > >::iterator l_d = eventListeners.begin();
+  for ( ; l_d != eventListeners.end(); ++l_d )
   {
-    std::pair< EventListener*, EventListenerData* > li_da = *l_d; /* copy to enable removal
-                                                                     of a listener from
-                                                                     _eventListeners by
-                                                                     its ProcessEvent() */
+    std::pair< EventListener*, EventListenerData* > li_da = *l_d;
+    if ( !_eventListeners.count( li_da.first )) continue;
+
     if ( li_da.first->myBusySM.insert( this ).second )
     {
+      const bool isDeletable = li_da.first->IsDeletable();
+
       li_da.first->ProcessEvent( event, eventType, this, li_da.second, hyp );
-      li_da.first->myBusySM.erase( this );
+
+      if ( !isDeletable || _eventListeners.count( li_da.first ))
+        li_da.first->myBusySM.erase( this ); // a listener is hopefully not dead
     }
   }
 }
@@ -2117,9 +2440,18 @@ void SMESH_subMesh::DeleteEventListener(EventListener* listener)
 {
   map< EventListener*, EventListenerData* >::iterator l_d =
     _eventListeners.find( listener );
-  if ( l_d != _eventListeners.end() ) {
-    if ( l_d->first  && l_d->first->IsDeletable() )  delete l_d->first;
-    if ( l_d->second && l_d->second->IsDeletable() ) delete l_d->second;
+  if ( l_d != _eventListeners.end() && l_d->first )
+  {
+    if ( l_d->second && l_d->second->IsDeletable() )
+    {
+      delete l_d->second;
+    }
+    l_d->first->myBusySM.erase( this );
+    if ( l_d->first->IsDeletable() )
+    {
+      l_d->first->BeforeDelete( this, l_d->second );
+      delete l_d->first;
+    }
     _eventListeners.erase( l_d );
   }
 }
@@ -2201,6 +2533,7 @@ void SMESH_subMeshEventListener::ProcessEvent(const int          event,
         (*smIt)->ComputeStateEngine( event );
       break;
     case SMESH_subMesh::COMPUTE:
+    case SMESH_subMesh::COMPUTE_SUBMESH:
       if ( subMesh->GetComputeState() == SMESH_subMesh::COMPUTE_OK )
         for ( ; smIt != smEnd; ++ smIt)
           (*smIt)->ComputeStateEngine( SMESH_subMesh::SUBMESH_COMPUTED );
@@ -2258,23 +2591,62 @@ namespace {
 //================================================================================
 
 SMESH_subMeshIteratorPtr SMESH_subMesh::getDependsOnIterator(const bool includeSelf,
-                                                             const bool reverse)
+                                                             const bool reverse) const
 {
+  SMESH_subMesh *me = (SMESH_subMesh*) this;
   SMESH_subMesh *prepend=0, *append=0;
   if ( includeSelf ) {
-    if ( reverse ) prepend = this;
-    else            append = this;
+    if ( reverse ) prepend = me;
+    else            append = me;
   }
   typedef map < int, SMESH_subMesh * > TMap;
   if ( reverse )
   {
     return SMESH_subMeshIteratorPtr
-      ( new _Iterator( new SMDS_mapReverseIterator<TMap>( DependsOn() ), prepend, append ));
+      ( new _Iterator( new SMDS_mapReverseIterator<TMap>( me->DependsOn() ), prepend, append ));
   }
   {
     return SMESH_subMeshIteratorPtr
-      ( new _Iterator( new SMDS_mapIterator<TMap>( DependsOn() ), prepend, append ));
+      ( new _Iterator( new SMDS_mapIterator<TMap>( me->DependsOn() ), prepend, append ));
+  }
+}
+
+//================================================================================
+/*!
+ * \brief Returns ancestor sub-meshes. Finds them if not yet found.
+ */
+//================================================================================
+
+const std::vector< SMESH_subMesh * > & SMESH_subMesh::GetAncestors() const
+{
+  if ( _ancestors.empty() &&
+       !_subShape.IsSame( _father->GetShapeToMesh() ))
+  {
+    const TopTools_ListOfShape& ancShapes = _father->GetAncestors( _subShape );
+
+    SMESH_subMesh* me = const_cast< SMESH_subMesh* >( this );
+    me->_ancestors.reserve( ancShapes.Extent() );
+
+    TopTools_MapOfShape map;
+   
+    for ( TopTools_ListIteratorOfListOfShape it( ancShapes ); it.More(); it.Next() )
+      if ( SMESH_subMesh* sm = _father->GetSubMeshContaining( it.Value() ))
+        if ( map.Add( it.Value() ))
+          me->_ancestors.push_back( sm );
   }
+
+  return _ancestors;
+}
+
+//================================================================================
+/*!
+ * \brief Clears the vector of ancestor sub-meshes
+ */
+//================================================================================
+
+void SMESH_subMesh::ClearAncestors()
+{
+  _ancestors.clear();
 }
 
 //================================================================================