cooriented

Checks relative parity of two sequences. Can be used to evaluate the differential in simplicial homology.

Usage

Via npm:

npm install cooriented

console.log(require("cooriented")([0,1,2], [0,1,2])) // prints +1
console.log(require("cooriented")([0,1,2], [1,0,2])) // prints -1

require("cooriented")(a, b)

Computes the relative orientation of a vs b. This is done by evaluating the Vandermonde polynomials of degree n for a and b, then taking their quotient mod 3. If:

• a.length !== b.length
• OR the elements in a and b do not match
• OR either a or b contains any repeated elements

Then this returns 0.

Credits

(c) 2013 Mikola Lysenko.