export type Vector = number[];
export function dot(a: Vector, b: Vector): number {
const n: number = Math.min(a.length, b.length);
let s: number = 0;
for (let i: number = 0; i < n; i++) {
s += a[i] * b[i];
}
return s;
}
export function norm(a: Vector): number {
let s: number = 0;
for (let i: number = 0; i < a.length; i++) {
const x: number = a[i];
s += x * x;
}
return Math.sqrt(s);
}
export function l2Normalize(v: Vector): Vector {
const n: number = norm(v);
if (n === 0) {
return v.slice();
}
const out: Vector = new Array<number>(v.length);
for (let i: number = 0; i < v.length; i++) {
out[i] = v[i] / n;
}
return out;
}
export function cosineSimilarity(
a: Vector,
b: Vector,
normalize: boolean
): number {
if (normalize) {
const na: Vector = l2Normalize(a);
const nb: Vector = l2Normalize(b);
return dot(na, nb);
}
const denom: number = norm(a) * norm(b);
if (denom === 0) {
return 0;
}
return dot(a, b) / denom;
}
