對(duì)于np.array對(duì)象
創(chuàng)建兩個(gè)array對(duì)象
>>> import numpy as np
>>>
>>> a = np.array([[1,2],[3,4]])
>>> b = np.array([[5,6],[7,8]])
>>> a
array([[1, 2],
[3, 4]])
>>> b
array([[5, 6],
[7, 8]])
元素乘法
用a * b或者np.multiply(a,b)
>>> a*b
array([[ 5, 12],
[21, 32]])
>>> np.multiply(a,b)
array([[ 5, 12],
[21, 32]])
矩陣乘法
用np.dot(a,b)位喂、np.matmul(a,b) 或a.dot(b)
>>> np.dot(a,b)
array([[19, 22],
[43, 50]])
>>> np.matmul(a,b)
array([[19, 22],
[43, 50]])
>>> a.dot(b)
array([[19, 22],
[43, 50]])
對(duì)于np.matrix對(duì)象
兩個(gè)matrix對(duì)象
>>> a = np.matrix(a)
>>> b = np.matrix(b)
>>> a
matrix([[1, 2],
[3, 4]])
>>> b
matrix([[5, 6],
[7, 8]])
元素乘法
用np.multiply(a,b)
>>> np.multiply(a,b)
matrix([[ 5, 12],
[21, 32]])
矩陣乘法
用a * b浪耘、np.dot(a,b)、np.matmul(a,b) 或a.dot(b)
note：
對(duì)于matrix對(duì)象來說塑崖，a * b是矩陣乘法七冲。與array對(duì)象是不一樣的
>>> a*b
matrix([[19, 22],
[43, 50]])
>>> np.dot(a,b)
matrix([[19, 22],
[43, 50]])
>>> np.matmul(a,b)
matrix([[19, 22],
[43, 50]])
>>> a.dot(b)
matrix([[19, 22],
[43, 50]])
