python回归之旅-用python学习数学---2023-020

矩阵减法：

import pandas

import numpy as np

a=[1,2]

b=[3,4]

l1=np.shape(a)

l2=np.shape(b)

if l1==l2:

    c=np.subtract(a,b)

    

print(c)

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矩阵乘法（此处为点乘）

import pandas

import numpy as np

a=[[1,2,3],[3,4,5]]

b=[[3,4,5],[3,4,5],[3,4,5]]

l1=np.shape(a)

l2=np.shape(b)

c=[]

if l1[1]==l2[0]:

    c=np.dot(a,b)

    print(c)

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矩阵除法（这里总觉得那里不对）

import pandas

import numpy as np

a=[[1,2,3],[3,4,5],[3,4,5]]

b=[[3,4,5],[3,4,5],[3,4,5]]

a1=np.mat(a)

b1=np.mat(b)

l1=np.shape(a)

l2=np.shape(b)

c=[]

c=a1/b1

d=np.divide(a1,b1)

print(c,d)