本文介绍了numpy.polyval()的反函数的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想知道np.polyval()是否有一个方便的逆函数，我在其中给出y值并求解x?
I was wondering is there a convenient inverse function of np.polyval(), where I give the y value and it solves for x?
我知道我可以做到这一点的一种方法是:
I know one way I could do this is:
import numpy as np
# Set up the question
p = np.array([1, 1, -10])
y = 100
# Solve
p_temp = p
p_temp[-1] -= y
x = np.roots(p_temp)
不过，我的猜测最多的是，该代码的可读性差.有什么建议吗?
However my guess is most would agree on that this code has low readability. Any suggestions?
推荐答案
这样的事情怎么样?
In [19]: p = np.poly1d([1, 1, -10]) # Use a poly1d to represent the polynomial.
In [20]: y = 100
In [21]: (p - y).roots
Out[21]: array([-11., 10.])
poly1d对象实现算术运算以返回新的poly1d对象，因此p - y是新的poly1d:
The poly1d object implements the arithmetic operations to return a new poly1d object, so p - y is a new poly1d:
In [22]: p - y
Out[22]: poly1d([ 1, 1, -110])
poly1d的roots属性返回您期望的结果.
The roots attribute of a poly1d returns what you would expect.
这篇关于numpy.polyval()的反函数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！