【深度学习基础】：线性代数(三)_逆矩阵与伪逆矩阵

一、矩阵的逆

1. 定义

  

      2.Python

          2.1  Numpy

import numpy as np

A = np.array([[1,2],

            [3,4]])

# 求逆矩阵

A_inv = np.linalg.inv(A)

np.dot(A,A_inv)

          2.2  Scipy

import numpy as np
from scipy import linalg
A = np.array([[1,2],
            [3,4]])
# 求逆矩阵
A_inv = linalg.inv(A)
np.dot(A,A_inv)

 

二、Moore-Penrose伪逆

      1.定义

   

      2.性质

  

      3.Python

          3.1  Numpy

import numpy as np
A = np.array([[1,2],
             [3,4],
             [5,6]])
A_pinv = np.linalg.pinv(A)
np.dot(A_pinv,A)

          3.2 Scipy

import numpy as np
A = np.array([[1,2],
             [3,4],
             [5,6]])
A_pinv = np.linalg.pinv(A)
np.dot(A_pinv,A)