numpy.polynomial.laguerre.lagder

numpy.polynomial.laguerre.lagder(cs, m=1, scl=1)

Differentiate a Laguerre series.

Returns the series cs differentiated m times. At each iteration the result is multiplied by scl (the scaling factor is for use in a linear change of variable). The argument cs is the sequence of coefficients from lowest order “term” to highest, e.g., [1,2,3] represents the series P_0 + 2*P_1 + 3*P_2.

Parameters :

cs: array_like :

1-d array of Laguerre series coefficients ordered from low to high.

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)

Returns :

der : ndarray

Laguerre series of the derivative.

See also

lagint

Notes

In general, the result of differentiating a Laguerre series does not resemble the same operation on a power series. Thus the result of this function may be “un-intuitive,” albeit correct; see Examples section below.

Examples

>>> from numpy.polynomial.laguerre import lagder
>>> lagder([ 1.,  1.,  1., -3.])
array([ 1.,  2.,  3.])
>>> lagder([ 1.,  0.,  0., -4.,  3.], m=2)
array([ 1.,  2.,  3.])

Next topic

numpy.polynomial.laguerre.lagint

This Page