  Free Electron Lasers (FELs) are a solution for providing intense, coherent
and bright radiation in the hard X-ray regime. Due to the low wall-plug
efficiency of FEL facilities, it is crucial and additionally very useful to
develop complete and accurate simulation tools for better optimizing a FEL
interaction. The highly sophisticated dynamics involved in a FEL process was
the main obstacle hindering the development of general simulation tools for
this problem. We present a numerical algorithm based on finite difference time
domain/Particle in cell (FDTD/PIC) in a Lorentz boosted coordinate system which
is able to fulfil a full-wave simulation of a FEL process. The developed
software offers a suitable tool for the analysis of FEL interactions without
considering any of the usual approximations. A coordinate transformation to
bunch rest frame makes the very different length scales of bunch size, optical
wavelengths and the undulator period transform to values with the same order.
Consequently, FDTD/PIC simulations in conjunction with efficient
parallelization techniques make the full-wave simulation feasible using the
available computational resources. Several examples of free electron lasers are
analyzed using the developed software, the results are benchmarked based on
standard FEL codes and discussed in detail.
