/// <summary>
/// Free all used resources if there is any.
/// </summary>
public void Dispose()
{
if (Native.ToInt64() != 0)
{
CavernAmp.FFTCache_Dispose(Native);
}
}
/// <summary>
/// Minimizes the phase of a spectrum.
/// </summary>
/// <remarks>This function does not handle zeros in the spectrum.
/// Make sure there is a threshold before using this function.</remarks>
public static void MinimumPhaseSpectrum(Complex[] response, FFTCache cache = null)
{
bool customCache = false;
if (cache == null)
{
cache = new FFTCache(response.Length);
customCache = true;
}
int halfLength = response.Length / 2;
for (int i = 0; i < response.Length; ++i)
{
response[i] = Complex.Log(response[i].Real);
}
if (CavernAmp.Available)
{
CavernAmp.InPlaceIFFT(response, cache);
}
else
{
response.InPlaceIFFT(cache);
}
for (int i = 1; i < halfLength; ++i)
{
response[i].Real += response[^ i].Real;
/// <summary>
/// FFT cache constructor.
/// </summary>
public FFTCache(int size)
{
if (CavernAmp.Available)
{
Native = CavernAmp.FFTCache_Create(size);
return;
}
int halfSize = size / 2;
double step = -2 * Math.PI / size;
cos = new float[halfSize];
sin = new float[halfSize];
for (int i = 0; i < halfSize; ++i)
{
double rotation = i * step;
cos[i] = (float)Math.Cos(rotation);
sin[i] = (float)Math.Sin(rotation);
}
for (int depth = 0, maxDepth = QMath.Log2(size); depth < maxDepth; ++depth)
{
if (Even[depth] == null)
{
Even[depth] = new Complex[1 << depth];
Odd[depth] = new Complex[1 << depth];
}
}
}
/// <summary>
/// Inverse Fast Fourier Transform of a transformed signal, while keeping the source array allocation.
/// </summary>
public static void InPlaceIFFT(this Complex[] samples)
{
if (CavernAmp.Available)
{
CavernAmp.InPlaceIFFT(samples);
return;
}
using FFTCache cache = new FFTCache(samples.Length);
samples.InPlaceIFFT(cache);
}
public static void InPlaceFFT(this Complex[] samples, FFTCache cache)
{
if (CavernAmp.Available)
{
CavernAmp.InPlaceFFT(samples, cache);
}
else
{
ProcessFFT(samples, cache, QMath.Log2(samples.Length) - 1);
}
}
public static void InPlaceFFT(this float[] samples, FFTCache cache)
{
if (CavernAmp.Available)
{
CavernAmp.InPlaceFFT(samples, cache);
}
else
{
ProcessFFT(samples, cache);
}
}
public static void InPlaceFFT(this float[] samples)
{
if (CavernAmp.Available)
{
CavernAmp.InPlaceFFT(samples);
}
else
{
using FFTCache cache = new FFTCache(samples.Length);
ProcessFFT(samples, cache);
}
}
/// <summary>
/// Inverse Fast Fourier Transform of a transformed signal.
/// </summary>
public static Complex[] IFFT(this Complex[] samples, FFTCache cache)
{
samples = samples.FastClone();
if (CavernAmp.Available)
{
CavernAmp.InPlaceIFFT(samples, cache);
}
else
{
samples.InPlaceIFFT(cache);
}
return(samples);
}
/// <summary>
/// Inverse Fast Fourier Transform of a transformed signal.
/// </summary>
public static Complex[] IFFT(this Complex[] samples)
{
if (CavernAmp.Available)
{
samples = samples.FastClone();
CavernAmp.InPlaceIFFT(samples);
}
else
{
using FFTCache cache = new FFTCache(samples.Length);
samples.InPlaceIFFT(cache);
}
return(samples);
}
/// <summary>
/// Inverse Fast Fourier Transform of a transformed signal, while keeping the source array allocation.
/// </summary>
public static void InPlaceIFFT(this Complex[] samples, FFTCache cache)
{
if (CavernAmp.Available)
{
CavernAmp.InPlaceIFFT(samples, cache);
return;
}
ProcessIFFT(samples, cache, QMath.Log2(samples.Length) - 1);
float multiplier = 1f / samples.Length;
for (int i = 0; i < samples.Length; ++i)
{
samples[i].Real *= multiplier;
samples[i].Imaginary *= multiplier;
}
}