def step(x0, t, dt): #if prevent_blow_up: #clip = abs(x0)>30 #x0[clip] *= 0.1 return rk4(lambda t,x: dxdt(x), x0, np.nan, dt)
def step(x0, t0, dt): return rk4(lambda t,x: dxdt(x), x0, np.nan, dt)