在不反转系数的情况下利用poly1d多项式的导数

Question

我用poly1d和polyder来返回一个简单多项式的导数。

   3     2
1 x + 1 x + 1 x + 1

我看到这两个命令的简单组合并没有按照正确的顺序使用系数。

print(np.poly1d(P.polyder(c)))

我能用这样的衬垫吗？

print(np.poly1d(P.polyder(c)))

所以像上面这样的系数是正确的顺序吗？

Below is my code and output:

    import numpy as np
from numpy.polynomial import polynomial as P

print("")

c = (1, 1, 1, 1)

print("the array of coefficients for the polynomial")
print(c)

print("")

print("polynomial with coefficients and exponents")
print(np.poly1d(c))

print("")

print("array of coefficients of derivative of polynomial: lowest order coming first in the array")
d_c = P.polyder(c)
print(d_c)

print("")

print("reversing the array of coefficients for the derivative of the polynomial")
d_c = d_c[::-1]
print(d_c)

print("")

print("printing the derivative of the polynomial with exponents and coefficients")
print(np.poly1d(d_c))

print("")

print("printing the derivative of the polynomial without reversing the coefficient array after derivation")
print(np.poly1d(P.polyder(c)))

print("")

输出：

the array of coefficients for the polynomial
(1, 1, 1, 1)

polynomial with coefficients and exponents
   3     2
1 x + 1 x + 1 x + 1

array of coefficients of derivative of polynomial: lowest order coming first in the array
[ 1.  2.  3.]

reversing the array of coefficients for the derivative of the polynomial
[ 3.  2.  1.]

printing the derivative of the polynomial with exponents and coefficients
   2
3 x + 2 x + 1

printing the derivative of the polynomial without reversing the coefficient array after derivation
   2
1 x + 2 x + 3

Answer 1

对从deriv返回的对象使用np.poly1d方法

import numpy as np

p = np.poly1d([1, 3, 1, 0, 4])

print(p)
print(p.deriv(1))

有关可用方法的完整列表，请参见医生们。