There have been several widely used numerical techniques for modeling computational electrodynamics over the past few decades. The finite-difference-time-domain method (FDTD) is one approach that covers a wide frequency range with a single simulation run, and treats disperse material properties in a natural way. Finite-difference-time-domain method and method of moment codes have been written for forward computational electromagnetics. Efforts have been taken to efficiently write the codes and parallelize them such as with a multi-core parallel approach on a high performance computer (HPC) or parallel approach with a graphics processing unit (GPU). 2D and 3D frequency dependent finite-difference-time-domain methods have been implemented as well.