Epetra_Import:This class builds an import object for efficient importing of off-processor elements.
Epetra_Import is used to construct a communication plan that can be called repeatedly by computational classes such the Epetra matrix, vector and multivector classes to efficiently obtain off-processor elements. This class currently has one constructor, taking two Epetra_Map or Epetra_BlockMap objects. The first map specifies the global IDs of elements that we want to import later. The second map specifies the global IDs that are owned by the calling processor.