static double autocorrelationNormalizationFactorForAudioSamples(short[] samples) {
  ret autocorrelationNormalizationFactorForAudioSamples(samples, 0, l(samples));
}

static double autocorrelationNormalizationFactorForAudioSamples(short[] samples, int start, int end) {
  double max = sixteenBitAudioSampleToDouble(absShortMax(samples, start, end));
  ret sqr(max);
}

static double autocorrelationNormalizationFactorForAudioSamples(short[] samples, IntRange r) {
  ret autocorrelationNormalizationFactorForAudioSamples(samples, r.start, r.end);
}