Zeroth-order Bessel function Python
Question: Apologies for the simplicity of this question.

I would like to implement an equation in Python. In this equation, K_0 is the
zeroth-order modifed Bessel function.

What is the best way of implementing K_0 in Python?


Answer: No need to implement it; it's included. See the docs for the
[scipy.special](http://docs.scipy.org/doc/scipy/reference/special.html)
module, in particular the optimized common ones
[here](http://docs.scipy.org/doc/scipy/reference/special.html#faster-versions-
of-common-bessel-functions):

    
    
    >>> import scipy.special
    >>> print scipy.special.k0.__doc__
    k0(x[, out])
    
    y=k0(x) returns the modified Bessel function of the second kind (sometimes called the third kind) of
    order 0 at x.
    >>> scipy.special.k0(1)
    0.42102443824070823
    

or more generally:

    
    
    >>> print scipy.special.kn.__doc__
    kn(x1, x2[, out])
    
    y=kn(n,x) returns the modified Bessel function of the second kind (sometimes called the third kind) for
    integer order n at x.
    >>> scipy.special.kn(0, 1)
    0.42102443824070834
    

