Determination of electromagnetic energy and parameters by complementary and complementary-dual energy method

The complementary and complementary-dual variational principles and their expressions in static electric and magnetic field are discussed. This paper gives a general complementary-dual variational principle. By expanding the various methods of constructing approximate function, including the R-function introduced by the authors ,some experience and approaches of the energy method are summarized. The complementary and complementary - dual finite element methods are also investigated.