zCurrent = np.arange(-5, 5, 0.01)
xCurrent = np.zeros(len(zCurrent))
i = 0
mfx = np.zeros(len(zCurrent))
mfz = np.zeros(len(zCurrent))
while i < len(zCurrent):
    if (zCurrent[i] > (koeffZminus[0]-koeffZplus[0])/(koeffZplus[1]-koeffZminus[1])):
        mfz[i] = koeffZplus(zCurrent[i])
        mfx[i] = koeffXplus((mfz[i]-koeffXplus[0])/koeffXplus[1])
        xCurrent[i] = (mfz[i]-koeffXplus[0])/koeffXplus[1]
        #if (mfx[i] < )
    else:
        mfz[i] = koeffZminus(zCurrent[i])
        mfx[i] = koeffXminus((mfz[i]-koeffXminus[0])/koeffXminus[1])
        xCurrent[i] = (mfz[i]-koeffXminus[0])/koeffXminus[1]
    i =i + 1