/// <summary>
/// Verify if matches DFT.
/// </summary>
static void VerifyMatchesDft(
double[] samples,
int maximumErrorDecimalPlaces,
bool inverse,
Action<Complex[]> dft,
Func<double[], double[]> hartley)
{
var hartleyReal = hartley(samples);
var fourierComplex = ArrayHelpers.ConvertAll(samples, s => new Complex(s, inverse ? -s : s));
dft(fourierComplex);
var fourierReal = ArrayHelpers.ConvertAll(fourierComplex, s => s.Real);
AssertHelpers.AlmostEqual(fourierReal, hartleyReal, maximumErrorDecimalPlaces);
}