+//================================================================================
+/*!
+ * \brief Computes mesh without geometry
+ * \param aMesh - the mesh
+ * \param aHelper - helper that must be used for adding elements to \aaMesh
+ * \retval bool - is a success
+ */
+//================================================================================
+
+bool SMESH_Algo::Compute(SMESH_Mesh & /*aMesh*/, SMESH_MesherHelper* /*aHelper*/)
+{
+ return error( COMPERR_BAD_INPUT_MESH, "Mesh built on shape expected");
+}
+
+//================================================================================
+/*!
+ * \brief store error and comment and then return ( error == COMPERR_OK )
+ */
+//================================================================================
+
+bool SMESH_Algo::error(int error, const SMESH_Comment& comment)
+{
+ _error = error;
+ _comment = comment;
+ return ( error == COMPERR_OK );
+}
+
+//================================================================================
+/*!
+ * \brief store error and return ( error == COMPERR_OK )
+ */
+//================================================================================
+
+bool SMESH_Algo::error(SMESH_ComputeErrorPtr error)
+{
+ if ( error ) {
+ _error = error->myName;
+ _comment = error->myComment;
+ _badInputElements = error->myBadElements;
+ return error->IsOK();
+ }
+ return true;
+}
+
+//================================================================================
+/*!
+ * \brief return compute error
+ */
+//================================================================================
+
+SMESH_ComputeErrorPtr SMESH_Algo::GetComputeError() const
+{
+ SMESH_ComputeErrorPtr err = SMESH_ComputeError::New( _error, _comment, this );
+ // hope this method is called by only SMESH_subMesh after this->Compute()
+ err->myBadElements.splice( err->myBadElements.end(),
+ (list<const SMDS_MeshElement*>&) _badInputElements );
+ return err;
+}
+
+//================================================================================
+/*!
+ * \brief initialize compute error
+ */
+//================================================================================
+
+void SMESH_Algo::InitComputeError()
+{
+ _error = COMPERR_OK;
+ _comment.clear();
+ list<const SMDS_MeshElement*>::iterator elem = _badInputElements.begin();
+ for ( ; elem != _badInputElements.end(); ++elem )
+ if ( (*elem)->GetID() < 1 )
+ delete *elem;
+ _badInputElements.clear();
+}
+
+//================================================================================
+/*!
+ * \brief store a bad input element preventing computation,
+ * which may be a temporary one i.e. not residing the mesh,
+ * then it will be deleted by InitComputeError()
+ */
+//================================================================================
+
+void SMESH_Algo::addBadInputElement(const SMDS_MeshElement* elem)
+{
+ if ( elem )
+ _badInputElements.push_back( elem );
+}