Question

我正在使用python ODE来解决Van der Pol方程。我想要做的是找到在一次调用integ（t）方法期间调用ODE衍生物的次数。我使用的求解器是isoda。我试图找到在没有jacbian函数的一次调用期间调用导数的次数以及当我包含jacobian函数时调用jacobian函数的次数。

def modified_vanderpol_integrator_demo(dt_min=1e-3, dt_max=10., mu=100.):
    # define a class to store the number of calls   
    class F:

        def __init__(self):
            self.callsydot = 0
            self.callsjac = 0

        def ydot(self,t, y, mu):
            self.callsydot += 1
            x, v = y[0], y[1]
            return array([v, mu*(1- x*x)*v - x])
        def jac(self, t, y, mu):
            self.callsjac += 1

            return array([[0, 1], [2*mu*v*x - 1, mu*(1-x*x)]])

    Dt = linspace(dt_min, dt_max, 1000)
    Num_of_times1 = []
    Num_of_times2 = []
    for dt in Dt:
        xinitial = array([1.0, 2.0])    # initial value
        f1 = F()
        r1 = ode(f1.ydot)
        r1.set_integrator('lsoda')
        r1.set_initial_value(xinitial)
        r1.set_f_params(mu)     
        r1.integrate(dt)
        Num_of_times1.append(f1.callsydot)

        f2 = F()
        r2 = ode(f2.ydot, f2.jac)
        r2.set_integrator('lsoda', with_jacobian=True)
        r2.set_initial_value(xinitial)
        r2.set_f_params(mu)     
        r2.integrate(dt)
        Num_of_times2.append(f2.callsjac)


    plt.plot(Dt, Num_of_times1)
    plt.plot(Dt, Num_of_times2)
    plt.show()

当我运行此脚本时，我收到了消息

create_cb_arglist: Failed to build argument list (siz) with enough arguments (tot-opt) required by user-supplied function (siz,tot,opt=2,3,0).
Traceback (most recent call last):
  File "stiffequations.py", line 118, in <module>
    modified_vanderpol_integrator_demo(dt_min=1e-3, dt_max=10., mu=100.)
  File "stiffequations.py", line 111, in modified_vanderpol_integrator_demo
    r2.integrate(dt)
  File "/usr/local/lib/python2.7/dist-packages/scipy/integrate/_ode.py", line 394, in integrate
    self.f_params, self.jac_params)
  File "/usr/local/lib/python2.7/dist-packages/scipy/integrate/_ode.py", line 1193, in run
    y1, t, istate = self.runner(*args)
lsoda.error: failed in processing argument list for call-back jac.

为什么会发生这种情况以及如何解决？感谢。

Answer 1

我发现我的脚本出了什么问题。我忘了在雅各比方程式中设置参数。

r2.set_jac_params(mu)

lsoda.error：处理回调jac的参数列表失败

1 个答案: