`numpy.polynomial.polynomial:polyder`

source: /numpy/polynomial/polynomial.py :465

Signature

def polyder ( c , m = 1 , scl = 1 , axis = 0 )

Summary

Differentiate a polynomial.

Extended Summary

Returns the polynomial coefficients c differentiated m times along axis. At each iteration the result is multiplied by scl (the scaling factor is for use in a linear change of variable). The argument c is an array of coefficients from low to high degree along each axis, e.g., [1,2,3] represents the polynomial 1 + 2*x + 3*x**2 while [[1,2],[1,2]] represents 1 + 1*x + 2*y + 2*x*y if axis=0 is x and axis=1 is y.

Parameters

c : array_like: Array of polynomial coefficients. If c is multidimensional the different axis correspond to different variables with the degree in each axis given by the corresponding index.
m : int, optional: Number of derivatives taken, must be non-negative. (Default: 1)
scl : scalar, optional: Each differentiation is multiplied by scl. The end result is multiplication by scl**m. This is for use in a linear change of variable. (Default: 1)
axis : int, optional: Axis over which the derivative is taken. (Default: 0).

Returns

der : ndarray: Polynomial coefficients of the derivative.

Examples

from numpy.polynomial import polynomial as P
c = (1, 2, 3, 4)

✓

P.polyder(c)  # (d/dx)(c)

✗

P.polyder(c, 3)  # (d**3/dx**3)(c)
P.polyder(c, scl=-1)  # (d/d(-x))(c)

✓

P.polyder(c, 2, -1)  # (d**2/d(-x)**2)(c)

✗

Aliases

numpy.polynomial.Polynomial._der
numpy.polynomial.polynomial.polyder