export function mu(i: number, amplitudeSpect: Float32Array): number {
  var numerator = 0;
  var denominator = 0;
  for (var k = 0; k < amplitudeSpect.length; k++) {
    numerator += Math.pow(k, i) * Math.abs(amplitudeSpect[k]);
    denominator += amplitudeSpect[k];
  }
  return numerator / denominator;
}