function CommonFun.calcDamReDuc(srcUser, targetUser)
  if srcUser == nil or targetUser == nil then
    return 0
  end
  local DamSpike = srcUser:GetProperty("DamSpike_PEN")
  local DamReduc2 = targetUser:GetProperty("DamReduc")
  local ReduceLv = CommonFun.calcSpikeLv(srcUser, targetUser)
  local SkillDamReduc = CommonFun.calcSkillDamReduc(srcUser, targetUser)
  local A = 1 - (1 + 0.009 * ReduceLv + DamSpike - DamReduc2) * SkillDamReduc
  local mapid, maptype = srcUser:GetMapInfo()
  if (maptype == PVP_MAPS) and targetUser:GetNpcID() ~= 40022_EMPERIUM then
    local pvpReduce = 0
    local Master = targetUser:GetMasterUser()
    if targetUser:GetNpcID() == 0 or Master ~= nil then
      pvpReduce = 0.2
    end
    A = A < -1 and -1 or 1 < A and 1 or A
    A = math.floor(A * 1000) / 1000
    A = A + 0.3 * (1 - math.sin(A * 3.14 / 2)) + pvpReduce
  end
  if 0.9 <= A then
    A = 0.9
  end
  return A
end