public void FourierRadix2IsReversible(FourierOptions options)
{
var dft = new DiscreteFourierTransform();
var samples = SignalGenerator.Random((u, v) => new Complex(u, v), GetUniform(1), 0x8000);
var work = new Complex[samples.Length];
samples.CopyTo(work, 0);
dft.Radix2Forward(work, options);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
dft.Radix2Inverse(work, options);
AssertHelpers.ListAlmostEqual(samples, work, 12);
}
/// <summary>
/// Verify matches naive complex.
/// </summary>
static void VerifyMatchesNaiveComplex(
Complex[] samples,
int maximumErrorDecimalPlaces,
Func <Complex[], Complex[]> naive,
Action <Complex[]> fast)
{
var spectrumNaive = naive(samples);
var spectrumFast = new Complex[samples.Length];
samples.CopyTo(spectrumFast, 0);
fast(spectrumFast);
AssertHelpers.ListAlmostEqual(spectrumNaive, spectrumFast, maximumErrorDecimalPlaces);
}
public void HartleyNaiveIsReversible(HartleyOptions options)
{
var dht = new DiscreteHartleyTransform();
var samples = SignalGenerator.Random(x => x, GetUniform(1), 0x80);
var work = new double[samples.Length];
samples.CopyTo(work, 0);
work = dht.NaiveForward(work, options);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
work = dht.NaiveInverse(work, options);
AssertHelpers.ListAlmostEqual(samples, work, 12);
}
/// <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.ListAlmostEqual(fourierReal, hartleyReal, maximumErrorDecimalPlaces);
}
public void FourierDefaultTransformIsReversible()
{
var samples = SignalGenerator.Random((u, v) => new Complex(u, v), GetUniform(1), 0x7FFF);
var work = new Complex[samples.Length];
samples.CopyTo(work, 0);
Transform.FourierForward(work);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
Transform.FourierInverse(work);
AssertHelpers.ListAlmostEqual(samples, work, 10);
Transform.FourierInverse(work, FourierOptions.Default);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
Transform.FourierForward(work, FourierOptions.Default);
AssertHelpers.ListAlmostEqual(samples, work, 10);
}
