INTERFACE MixedEnergy;
IMPORT Energy;

TYPE
  T <: Public;
  Public = Energy.T OBJECT
      term: REF ARRAY OF Energy.T;             (* Energy ingredients *)
      weight: REF ARRAY OF REAL;               (* Weight of each ingredient *)
      termValue: REF ARRAY OF LONGREAL := NIL; (* Value of each term as of last "eval" *)
    METHODS

      init(
          READONLY term: ARRAY OF Energy.T;
          READONLY weight: ARRAY OF REAL
        ): T;
        (* 
          Allocates new arrays for "term", "weight", and "termValue",
          and copies the given arrays into them.
          Assumes the "term[k]" has been initialized. *)
    END;
  (*
    A "MixedEnergy.T" is a linear combinations of the energy functions "term[k]",
    with weights "weight[k]". The "eval" method will leave the (unweighted)
    energy terms in "termValue". *)
    
END MixedEnergy.