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# numpy.polynomial.hermite_e.hermeder

polynomial.hermite_e.hermeder(c, m=1, scl=1, axis=0)

  Differentiate a Hermite_e series.

  Returns the series 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 series `1*He_0 + 2*He_1 + 3*He_2` while [[1,2],[1,2]] represents `1*He_0(x)*He_0(y) + 1*He_1(x)*He_0(y) + 2*He_0(x)*He_1(y) + 2*He_1(x)*He_1(y)` if axis=0 is `x` and axis=1 is `y`.

  Parameters:
    c array_like

      Array of Hermite_e series 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

      Hermite series of the derivative.

  See also

  `hermeint`

  Notes

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

  Examples

      >>> from numpy.polynomial.hermite_e import hermeder
      >>> hermeder([ 1.,  1.,  1.,  1.])
      array([1.,  2.,  3.])
      >>> hermeder([-0.25,  1.,  1./2.,  1./3.,  1./4 ], m=2)
      array([1.,  2.,  3.])