Pure-JS implementation of the Bessel functions (J,Y,I,K), for node and browser

The standard notation is used here:

• J is the Bessel function of the first kind
• Y is the Bessel function of the second kind
• I is the modified Bessel function of the first kind
• K is the modified Bessel function of the first kind

The functions besselj, bessely, besseli, besselk are exposed when you include the script bessel.js:

<script src="bessel.js"></script> <script>console.log(besselj(1,2));</script> 

See test.html for an example

In node, those four functions are exported:

var besselj01 = require('bessel').besselj(0,1); 

Each function follows Excel semantics (value, function-order). For example,

bessel.besselj(1.5, 1) 

is the value of the bessel function J1 at the point x=1.5