python 中的 numpy.polyint()
numpy.polyint(p, m) : 计算指定阶数的多项式的反导数。
多项式“P”的 m 个反导数“P”满足
参数: p:【array _ like 或 poly1D】多项式系数按幂次递减顺序给出。如果第二个参数(根)设置为真，那么数组值就是多项式方程的根。比如 poly1d(3，2，6)= 3x2+2x+6 m:【int，可选】反导数的顺序。默认值为 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
