# scipy.special.modstruve¶

scipy.special.modstruve(v, x) = <ufunc 'modstruve'>

Modified Struve function.

Return the value of the modified Struve function of order v at x. The modified Struve function is defined as,

$L_v(x) = -\imath \exp(-\pi\imath v/2) H_v(\imath x),$

where $$H_v$$ is the Struve function.

Parameters
varray_like

Order of the modified Struve function (float).

xarray_like

Argument of the Struve function (float; must be positive unless v is an integer).

Returns
Lndarray

Value of the modified Struve function of order v at x.

Notes

Three methods discussed in [1] are used to evaluate the function:

• power series

• expansion in Bessel functions (if $$|x| < |v| + 20$$)

• asymptotic large-x expansion (if $$x \geq 0.7v + 12$$)

Rounding errors are estimated based on the largest terms in the sums, and the result associated with the smallest error is returned.

References

1

NIST Digital Library of Mathematical Functions https://dlmf.nist.gov/11

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