数组加法/乘法

• $*$仅对应位置相乘
• $@及.dot$矩阵相乘

a = np.array([[10, 20], [40, 50]])
b = np.array([[1, 2], [4, 5]])
print(a)
print(b)
print(a + b)
print(a * b)
print(a @ b)
print(a .dot(b))