# scipy.special.h_roots¶

scipy.special.h_roots(n, mu=False)[source]

Computes the sample points and weights for Gauss-Hermite quadrature. The sample points are the roots of the n-th degree Hermite polynomial, $$H_n(x)$$. These sample points and weights correctly integrate polynomials of degree $$2n - 1$$ or less over the interval $$[-\infty, \infty]$$ with weight function $$f(x) = e^{-x^2}$$.

Parameters: n : int quadrature order mu : bool, optional If True, return the sum of the weights, optional. x : ndarray Sample points w : ndarray Weights mu : float Sum of the weights

Notes

For small n up to 150 a modified version of the Golub-Welsch algorithm is used. Nodes are computed from the eigenvalue problem and improved by one step of a Newton iteration. The weights are computed from the well-known analytical formula.

For n larger than 150 an optimal asymptotic algorithm is applied which computes nodes and weights in a numerically stable manner. The algorithm has linear runtime making computation for very large n (several thousand or more) feasible.

References

 [townsend.trogdon.olver-2014] Townsend, A. and Trogdon, T. and Olver, S. (2014) Fast computation of Gauss quadrature nodes and weights on the whole real line. ArXiv 1410.5286.
 [townsend.trogdon.olver-2015] Townsend, A. and Trogdon, T. and Olver, S. (2015) Fast computation of Gauss quadrature nodes and weights on the whole real line. IMA Journal of Numerical Analysis doi: 10.1093/imanum/drv002

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