Effects: These functions compute the cylindrical Neumann functions,
also known as the cylindrical Bessel functions of the second kind,
of their respective arguments
nu and x.
Returns: Nν(x)=⎧⎪
⎪
⎪
⎪
⎪
⎪
⎪⎨⎪
⎪
⎪
⎪
⎪
⎪
⎪⎩Jν(x)cosνπ−J−ν(x)sinνπ,for x≥0 and non-integral νlimμ→νJμ(x)cosμπ−J−μ(x)sinμπ,for x≥0 and integral ν
where
ν is nu and
x is x.