# naginterfaces.library.specfun.bessel_​k1_​scaled¶

naginterfaces.library.specfun.bessel_k1_scaled(x)[source]

bessel_k1_scaled returns a value of the scaled modified Bessel function .

For full information please refer to the NAG Library document for s18cd

https://www.nag.com/numeric/nl/nagdoc_28.5/flhtml/s/s18cdf.html

Parameters
xfloat

The argument of the function.

Returns
sk1float

The value of the function at .

Raises
NagValueError
(errno )

On entry, .

Constraint: .

is undefined and the function returns zero.

(errno )

On entry, .

Constraint: .

The function returns the value of the function at the smallest permitted value of the argument.

Notes

bessel_k1_scaled evaluates an approximation to , where is a modified Bessel function of the second kind. The scaling factor removes most of the variation in .

The function uses the same Chebyshev expansions as bessel_k1_real(), which returns the unscaled value of .

References

NIST Digital Library of Mathematical Functions