Python numpy.polyint()

numpy.polyint(p, m) :评估一个指定阶数的多项式的反导数。

多项式’p’的反导数’P’满足如下条件

参数 :
p :[array_like or poly1D] 多项式系数按照幂的递减顺序给出。如果第二个参数（根）被设置为True，那么数组值就是多项式方程的根。例如，poly1d(3, 2, 6) = 3x 2+ 2x + 6
m :[int, optional] 反衍生物的顺序。默认为1。

返回:多项式的反导数。

代码 #1:

# Python code explaining  
# numpy.polyint() 
      
# importing libraries 
import numpy as np 
    
# Constructing polynomial  
p1 = np.poly1d([1, 2])  
p2 = np.poly1d([4, 9, 5, 4])  
      
print ("P1 : ", p1)  
print ("\n p2 : \n", p2) 
  
# Solve for x = 2  
print ("\n\np1 at x = 2 : ", p1(2))  
print ("p2 at x = 2 : ", p2(2))  
  
a = np.polyint(p1, 1) 
b = np.polyint(p2, 1) 
print ("\n\nUsing polyint") 
print ("p1 anti-derivative of order = 1 : \n", a) 
print ("p2 anti-derivative of order = 1 : \n", b) 
  
a = np.polyint(p1, 2) 
b = np.polyint(p2, 2) 
print ("\n\nUsing polyint") 
print ("p1 anti-derivative of order = 2 : \n", a) 
print ("p2 anti-derivative of order = 2 : \n", b) 

输出 :

P1 :   
1 x + 2

 p2 : 
    3     2
4 x + 9 x + 5 x + 4


p1 at x = 2 :  4
p2 at x = 2 :  82


Using polyint
p1 anti-derivative of order = 1 : 
      2
0.5 x + 2 x
p2 anti-derivative of order = 1 : 
    4     3       2
1 x + 3 x + 2.5 x + 4 x

代码 #2:

# Python code explaining  
# numpy.polyint() 
       
# importing libraries 
import numpy as np 
     
# Constructing polynomial  
p1 = np.poly1d([1, 2])  
p2 = np.poly1d([4, 9, 5, 4])  
     
a = np.polyint(p1, 2) 
b = np.polyint(p2, 2) 
  
print ("\n\nUsing polyint") 
print ("p1 anti-derivative of order = 2 : \n", a) 
print ("p2 anti-derivative of order = 2 : \n", b) 

输出 :

Using polyint
p1 anti-derivative of order = 2 : 
         3     2
0.1667 x + 1 x
p2 anti-derivative of order = 2 : 
      5        4          3     2
0.2 x + 0.75 x + 0.8333 x + 2 x