def METHOD_NAME(w):
    u = w["disp"]
    p = w["press"]
    Js = .5 * (lmbda + p + 2. * np.sqrt(lmbda * mu + .25 * (lmbda + p) ** 2)) / lmbda
    dJsdp = ((.25 * lmbda + .25 * p + .5 * np.sqrt(lmbda * mu + .25 * (lmbda + p) ** 2))
             / (lmbda * np.sqrt(lmbda * mu + .25 * (lmbda + p) ** 2)))
    d2Jdp2 = .25 * mu / (lmbda * mu + .25 * (lmbda + p) ** 2) ** (3/2)
    L = (-2. * dJsdp - p * d2Jdp2 + mu / Js ** 2 * dJsdp ** 2 - mu / Js * d2Jdp2
         + lmbda * (Js - 1.) * d2Jdp2 + lmbda * dJsdp ** 2)
    return L