pc_grate,pc-grate,pcgrate,grating,echelle,diffraction gratings,ruled gratings,holographic gratings,optical software,diffraction analysis,electromagnetic theory,integral method,efficiency calculations,diffraction efficiency,relief multi-layer gratings,hcp,tsp,np-complete problems,np-hard problems,hamiltonian cycle,leaper graphs,knight graphs,traveling salesman problem,traveling salesperson problem,polynomial approximation algorithms

international intellectual group, inc. (i.i.g., inc.) is a small private company which was established in 1996 by specialists from the usa and russia for development and distribution of new scientific software with applications in optics, physics, discrete mathematics and computer science.