afryca.ase.Snippet Library distance

var distance = (typeof exports === "undefined")?(function distance() {}):(exports);
if(typeof global !== "undefined") { global.distance = distance; }

distance.kemeny = function kemeny(r1, r2) {
	var result;
	if ((r1 != null) && (r2 != null)) {
		if (r1.length == r2.length) {
			result = 0;
			var v1;
			var v2;
			var n = r1.length;
			for (var l = 0; l < (n - 1); l++) {
				for (var k = l + 1; k < n; k++) {
					v1 = r1[l] - r1[k]; // v1{(0,equals),(<0,o(l)0,o(l)>o(k)}
					v2 = r2[l] - r2[k]; // v2{(0,equals),(<0,o(l)0,o(l)>o(k)}

					if ((v1 < 0) && (v2 > 0)) {
						result += 1;
					} else if ((v1 > 0) && (v2 < 0)) {
						result += 1;
					} else if ((v1 == 0) && (v2 != 0)) {
						result += 0.5;
					} else if ((v1 != 0) && (v2 == 0)) {
						result += 0.5;
					}
				}
			}
		}
	}
	return result;
}

distance.normalizeKemeny = function normalizeKemeny(kemeny, numberOfElements) {
	var result;
	if (numberOfElements > 0) {
		result = (2 * kemeny) / (numberOfElements * (numberOfElements - 1));
	}
	return result;
}

distance.normalizedKemeny = function normalizedKemeny(r1, r2) {
	return distance.normalizeKemeny(distance.kemeny(r1, r2), r1.length);
}

distance