Exact arithmetic test to check if (n+2) points are cospherical.
(Very) loosely inspired by Jonathan Shewchuk's work on robust predicates. Currently not as fast, but pull requests are welcome.
var inSphere = require("robust-in-sphere") console.log(inSphere( [0, 1], [1, 0], [-1, 0], [0, -1]))
npm install robust-in-sphere
var inSphere = require("robust-in-sphere")
Tests if a collection of
n+2 points in
n-dimensional space are cospherical or if the last point is contained in the sphere or not.
a,b,c,...is a list of points
Returns A signed integer that gives the orientation of the points
<0if the last point is contained in the oriented sphere defined by the previous two points
>0if the last point is outside the sphere
0is the points are cospherical
Notes Up to 6 points it is possible to get a specialized version of
inSphere that avoids an extra dispatch using the syntax:
inSphere(a,b,c,d) === inSphere(a,b,c,d)
(c) 2014 Mikola Lysenko. MIT License