private:
/** Vector of atomized strings (using a vector allows faster unarchiving). */
mutable std::vector<std::string> atoms;
+ /** The map of from strings to indices of the atoms vectors allows for
+ * faster archiving.
+ */
+ typedef std::map<std::string, archive_atom>::const_iterator inv_at_cit;
+ mutable std::map<std::string, archive_atom> inverse_atoms;
/** Map of stored expressions to nodes for faster archiving */
typedef std::map<ex, archive_node_id, ex_is_less>::iterator mapit;