如何通过多处理获得for循环中不同函数的返回值

Question

我正在为当前的模拟制作一些数值解算器。为了使我的代码更快，我做了一个函数，返回元素矩阵乘法的结果，梯度。。。等等

    def mmul(A, B, procname, return_dict):
        return_dict[procname] = np.multiply(A,B)
    def mgrad(A, procname, return_dict):
        return_dict[procname] = np.gradient(A/dx)
    def madd(A, B, procname, return_dict):
        return_dict[procname] = A+B

下面是代码的主体。我首先制作了一个字典（return_dict）并存储每个处理单元的结果，然后从字典中获取值（Vgrad、Pgrad、Psquare）

    for k in range(0,max_iter-1, 1):
        #0. Firstly generate all of the auxiliay calculation arrays 
        post_V, post_p, Vij_coeff = np.zeros((3, lx, ly), dtype = float)

        # Calculate carrier density of the next step
        processes = []
        #----------------------------                                 # Const/mtx for calculating p
        manager = multiprocessing.Manager()
        return_dict = manager.dict()
        p0 = multiprocessing.Process(target = mgrad, args = (V, Vgrad, return_dict))
        processes.append(p0)
        p0.start()
        p1 = multiprocessing.Process(target = mgrad, args = (p, Pgrad, return_dict))
        processes.append(p1);p1.start()
        p2 = multiprocessing.Process(target = mmul, args = (p,p, Psquare, return_dict))
        processes.append(p2);p2.start()
        for process in processes:
            process.join()
        Vgrad = return_dict['Vgrad']
        Pgrad = return_dict['Pgrad']
        Psquare = return_dict['Psquare']

但是，此代码会产生以下错误

    PicklingError: Can't pickle <function mgrad at 0x000002776C3614C8>: it's not the same object as __main__.mgrad

在多处理器中运行时，是否有任何解决方案可以获得函数的计算值