# naginterfaces.library.specfun.bessel_​i1_​scaled¶

naginterfaces.library.specfun.bessel_i1_scaled(x)[source]

bessel_i1_scaled returns a value of the scaled modified Bessel function .

For full information please refer to the NAG Library document for s18cf

https://www.nag.com/numeric/nl/nagdoc_28.5/flhtml/s/s18cff.html

Parameters
xfloat

The argument of the function.

Returns
si1float

The value of the function at .

Notes

bessel_i1_scaled evaluates an approximation to , where is a modified Bessel function of the first kind. The scaling factor removes most of the variation in .

The function uses the same Chebyshev expansions as bessel_i1_real(), which returns the unscaled value of .

References

NIST Digital Library of Mathematical Functions