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


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.


(c) 2013 Mikola Lysenko.