用numpy计算弹性碰撞

Question

我尝试计算与numpy的弹性碰撞，但在编写脚本时发现丢失：

def elasticCollisionFormular():
    while True:
        try:
            A = np.array([[m1,m2],[0.5*m1,0.5*m2]])
            B = np.array([[v1,v2],[v1**2,v2**2]])
            C = np.array([[m1,m2],[0.5*m1,0.5*m2]])
            D = np.linalg.solve(A*B,C)
        except:
            print('An error occured. Retrying...')
            continue
        else:
            return D
            break

我得到的D不正确，应该如何安排D = np.linalg.solve(A*B,C)？

一个示例及其正确答案：

m1 = 3

m2 = 1

v1 = 4

v2 = 8

v₁' = -2 and 4

v₂' = 10 and -8

顺便说一下，这是公式：

编辑： 完整代码在这里：

import numpy as np

def ask_for_m1():
    while True:
        try:
            m1 = int(input('Enter the mass of object 1 :'))
        except:
            print('An error occured, please try again')
            continue
        else:
            return m1
            break

def ask_for_m2():
    while True:
        try:
            m2 = int(input('Enter the mass of object 2 :'))
        except ImportError:
            print('An error occured, please try again')
            continue
        else:
            return m2
            break

def ask_for_v1():
    while True:
        try:
            v1 = int(input('Enter the staring speed of object 1 :'))
        except:
            print('An error occured, please try again')
            continue
        else:
            return v1
            break

def ask_for_v2():
    while True:
        try:
            v2 = int(input('Enter the staring speed of object 2 :'))
        except:
            print('An error occured, please try again')
            continue
        else:
            return v2
            break

def elasticCollisionFormular():
    while True:
        try:
            A = np.array([[m1,m2],[0.5*m1,0.5*m2]])
            B = np.array([[v1,v2],[v1**2,v2**2]])
            C = np.array([[m1,m2],[0.5*m1,0.5*m2]])
            D = np.linalg.solve(A*B,C)
        except:
            print('An error occured. Retrying...')
            continue
        else:
            return D
            break


#start of program

while True:
    m1 = ask_for_m1()
    m2 = ask_for_m2()
    v1 = ask_for_v1()
    v2 = ask_for_v2()
    D = elasticCollisionFormular()
    print(D)

和我设置的metrix变量（A，B，C，D）：