code: def cal_g_bm3(p, g, k):
      
      v = cal_v_bm3(p, k)
      v0 = k[0]
      k0 = k[1]
      kp = k[2]
      g0 = g[0]
      gp = g[1]
      f = 0.5 * ((v / v0)**(-2. / 3.) - 1.)
      return (1. + 2. * f)**(5. / 2.) * (g0 + (3. * k0 * gp - 5. * g0) * f +
                                         (6. * k0 * gp - 24. * k0 - 14. * g0 +
                                          9. / 2. * k0 * kp) * f**2.)
docs: calculate shear modulus at given pressure
  
      :param p: pressure
      :param g: [g0, g0p]
      :param k: [v0, k0, k0p]
      :return: shear modulus at high pressure