!Copyright (c) 2013 by tdem.org under guide of Xiu Li(lixiu@chd.edu.cn)
!written by Huaifeng Sun(sunhuaifeng@gmail.com) and Xushan Lu(luxushan@gmail.com)
!Code distribution @ tdem.org or sunhuaifeng.com
    
SUBROUTINE ZERO
  USE CONSTANTPARAMETERS
  USE ELECTROMAGNETIC_VARIABLES
  USE RES_MODEL_PARAMETER
  USE TIME_PARAMETER
  USE PML_PARAMETER
  USE OMP_LIB
  !>This subroutine will initialize the array in the calculation by setting all its elements to zero.
  IMPLICIT NONE
  CCSIG=0.0D0
  CCSIGX=0.0D0
  CCSIGY=0.0D0
  CCSIGZ=0.0D0
  EX=0.0D0
  EY=0.0D0
  EZ=0.0D0
  HX=0.0D0
  HY=0.0D0
  HZ=0.0D0
  !>CPML arrays: den_* is always initialized to 1.0 (neutral value), so the
  !! iteration loop can always multiply the curl terms by den_*; the scheme
  !! degenerates exactly to the original version when Logic_PML=0.
  den_ex=1.0D0
  den_ey=1.0D0
  den_ez=1.0D0
  den_hx=1.0D0
  den_hy=1.0D0
  den_hz=1.0D0
  c_h_zz=0.0D0
  inv_hz_den=1.0D0
  IF(Logic_PML==1)THEN
     psi_Eyx_1=0.0D0
     psi_Eyx_2=0.0D0
     psi_Ezx_1=0.0D0
     psi_Ezx_2=0.0D0
     psi_Ezy_1=0.0D0
     psi_Ezy_2=0.0D0
     psi_Exy_1=0.0D0
     psi_Exy_2=0.0D0
     psi_Exz_1=0.0D0
     psi_Exz_2=0.0D0
     psi_Eyz_1=0.0D0
     psi_Eyz_2=0.0D0
     psi_Hyx_1=0.0D0
     psi_Hyx_2=0.0D0
     psi_Hzx_1=0.0D0
     psi_Hzx_2=0.0D0
     psi_Hxy_1=0.0D0
     psi_Hxy_2=0.0D0
     psi_Hzy_1=0.0D0
     psi_Hzy_2=0.0D0
     psi_Hxz_1=0.0D0
     psi_Hxz_2=0.0D0
     psi_Hyz_1=0.0D0
     psi_Hyz_2=0.0D0
     psi_Hzz_1=0.0D0
     psi_Hzz_2=0.0D0
  ENDIF
  RETURN
ENDSUBROUTINE ZERO