public void FourierBluesteinIsReversible(FourierOptions options)
{
var samples = Generate.RandomComplex(0x7FFF, GetUniform(1));
var work = new Complex[samples.Length];
samples.CopyTo(work, 0);
Fourier.BluesteinForward(work, options);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
Fourier.BluesteinInverse(work, options);
AssertHelpers.AlmostEqual(samples, work, 10);
}
private (double[] real, double[] imaginary) CalculateFFT()
{
const int roundDecimals = 2;
var real = GetRealPart();
var imaginary = GetImaginaryPart();
Fourier.Forward(real, imaginary);
Round(real, roundDecimals);
Round(imaginary, roundDecimals);
return(real, imaginary);
}
public void FourierRadix2IsReversible32(FourierOptions options)
{
var samples = Generate.RandomComplex32(0x8000, GetUniform(1));
var work = new Complex32[samples.Length];
samples.CopyTo(work, 0);
Fourier.Forward(work, options);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
Fourier.Inverse(work, options);
AssertHelpers.AlmostEqual(samples, work, 12);
}
public void FourierRealIsReversible(FourierOptions options)
{
var samples = Generate.Random(0x7FFF, GetUniform(1));
var work = new double[samples.Length + 2];
samples.CopyTo(work, 0);
Fourier.ForwardReal(work, samples.Length, options);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
Fourier.InverseReal(work, samples.Length, options);
AssertHelpers.AlmostEqual(samples, work, 10);
}
private void ComputeKernelTilde()
{
//Evaluate the kernel at the interpolation nodes and form the embedded generating kernel vector for a circulant matrix
for (int i = 0; i < n_interpolation_points_1d; i++)
{
kernel_tilde[n_interpolation_points_1d + i]
= kernel_tilde[n_interpolation_points_1d - i]
= SquaredCauchy(tilde[0], tilde[i]);
}
// Precompute the FFT of the kernel generating matrix
Fourier.ForwardReal(kernel_tilde, 2 * n_interpolation_points_1d, FourierOptions.NoScaling);
}
public static void AnalyseGenerated(int frequency)
{
var samples = Generate.Sinusoidal(1024, 44100, frequency, 1.0)
.Select(sample => new Complex32((float)sample, 0))
.ToArray();
Fourier.Forward(samples);
var results = samples.Take(256).Select(result => result.Magnitude);
Console.WriteLine($"FFT results: {FormatResults(results)}");
Console.WriteLine(new String('-', 80));
SaveResultsToCsvFile($"../js/signals/{frequency}_from_generated_data.csv", results);
}
public void FourierNaiveIsReversible(FourierOptions options)
{
var samples = Generate.RandomComplex(0x80, GetUniform(1));
var work = new Complex[samples.Length];
samples.CopyTo(work, 0);
work = Fourier.NaiveForward(work, options);
Assert.IsFalse(work.ListAlmostEqual(samples, 6));
work = Fourier.NaiveInverse(work, options);
AssertHelpers.AlmostEqual(samples, work, 12);
}
public static IObservable <FftResult> AudioSampleFft(this IObservable <double[]> obs, double sampleRate)
{
return(obs.Select(x =>
{
var copy = x.Select(y => new Complex(y, 0)).ToArray();
Fourier.Forward(copy, FourierOptions.AsymmetricScaling);
return new FftResult(
Fourier.FrequencyScale(x.Length, sampleRate),
copy
);
}));
}
private static Complex[] fourier(double[] data)
{
Complex[] complexData = new Complex[data.Length];
int count = 0;
foreach (double x in data)
{
complexData[count] = x;
count++;
}
Fourier.Forward(complexData, FourierOptions.Default);//フーリエ変換
return(complexData);
}
public void FourierDefaultTransformSatisfiesParsevalsTheorem32(int count)
{
var samples = Generate.RandomComplex32(count, GetUniform(1));
var timeSpaceEnergy = (from s in samples select s.MagnitudeSquared()).Mean();
var spectrum = new Complex32[samples.Length];
samples.CopyTo(spectrum, 0);
Fourier.Forward(spectrum);
var frequencySpaceEnergy = (from s in spectrum select s.MagnitudeSquared()).Mean();
Assert.AreEqual(timeSpaceEnergy, frequencySpaceEnergy, 1e-7);
}
private void button2_Click(object sender, EventArgs e)
{
if (GlobalVar.refresh == 0)
{
button1_Click(sender, e); // Refresh first
GlobalVar.refresh = 1;
button2_Click(sender, e); // Try again
}
else
{
GFFT1.Series[0].Points.Clear();
GFFT2.Series[0].Points.Clear();
double dintervals = 1000;
int att = 30;
int fs1 = 2700;
int fs2 = 3500;
Fourier.Forward(GlobalVar.compoutputA1);
for (int q = 0; q < dintervals; q++)
{
GFFT1.ChartAreas[0].AxisX.Title = "Frequency (Hz)";
GFFT1.ChartAreas[0].AxisY.Title = "Amplitude";
GFFT1.Series[0].IsVisibleInLegend = false; // Saves space
GFFT1.ChartAreas[0].AxisY.Minimum = 0;
GFFT1.ChartAreas[0].AxisX.Minimum = 0;
GFFT1.ChartAreas[0].AxisX.Maximum = 5500;
GFFT2.ChartAreas[0].AxisX.Title = "Frequency (Hz)";
GFFT2.ChartAreas[0].AxisY.Title = "Amplitude";
GFFT2.Series[0].IsVisibleInLegend = false; // Saves space
GFFT2.ChartAreas[0].AxisY.Minimum = 0;
GFFT2.ChartAreas[0].AxisX.Minimum = 0;
GFFT2.ChartAreas[0].AxisX.Maximum = 5500;
if (GlobalVar.samplef / dintervals * q < fs2 && fs1 < GlobalVar.samplef / dintervals * q)
{
GFFT1.Series[0].Points.Add(new DataPoint(GlobalVar.samplef / dintervals * q, 15 * Math.Log10(GlobalVar.compoutputA1[q].Magnitude) - att));
GFFT2.Series[0].Points.Add(new DataPoint(GlobalVar.samplef / dintervals * q, 15 * Math.Log10(GlobalVar.compoutputA1[q].Magnitude) - att));
}
else if (20 * Math.Log10(GlobalVar.compoutputA1[q].Magnitude) > 0)
{
GFFT1.Series[0].Points.Add(new DataPoint(GlobalVar.samplef / dintervals * q, 15 * Math.Log10(GlobalVar.compoutputA1[q].Magnitude)));
GFFT2.Series[0].Points.Add(new DataPoint(GlobalVar.samplef / dintervals * q, 15 * Math.Log10(GlobalVar.compoutputA1[q].Magnitude)));
}
else
{
GFFT1.Series[0].Points.Add(new DataPoint(GlobalVar.samplef / dintervals * q, 0));
}
}
}
}
protected override void OnResize(EventArgs e)
{
base.OnResize(e);
if (ClientRectangle.Width <= AxisMargin || ClientRectangle.Height <= AxisMargin)
{
return;
}
var temp = new byte[ClientRectangle.Width - 2 * AxisMargin];
Fourier.SmoothCopy(_powerSpectrum, temp, _powerSpectrum.Length, (_temp.Length + temp.Length) / (float)_temp.Length, 0);
_powerSpectrum = temp;
_temp = new byte[_powerSpectrum.Length];
var oldBuffer = _buffer;
_buffer = new Bitmap(ClientRectangle.Width, ClientRectangle.Height, PixelFormat.Format32bppPArgb);
var oldBuffer2 = _buffer2;
_buffer2 = new Bitmap(ClientRectangle.Width, ClientRectangle.Height, PixelFormat.Format32bppPArgb);
_graphics.Dispose();
_graphics = Graphics.FromImage(_buffer);
SpectrumAnalyzer.ConfigureGraphics(_graphics);
_graphics2.Dispose();
_graphics2 = Graphics.FromImage(_buffer2);
SpectrumAnalyzer.ConfigureGraphics(_graphics2);
_graphics.Clear(Color.Black);
var rect = new Rectangle(AxisMargin, 0, _buffer.Width - 2 * AxisMargin, _buffer.Height);
_graphics.DrawImage(oldBuffer, rect, AxisMargin, 0, oldBuffer.Width - 2 * AxisMargin, oldBuffer.Height, GraphicsUnit.Pixel);
oldBuffer.Dispose();
oldBuffer2.Dispose();
if (_spectrumWidth > 0)
{
_xIncrement = _scale * (ClientRectangle.Width - 2 * AxisMargin) / _spectrumWidth;
}
_gradientBrush.Dispose();
_gradientBrush = new LinearGradientBrush(new Rectangle(AxisMargin / 2, AxisMargin / 2, Width - AxisMargin / 2, ClientRectangle.Height - AxisMargin / 2), Color.White, Color.Black, LinearGradientMode.Vertical);
_gradientPixels = null;
_gradientBrush.InterpolationColors = _gradientColorBlend;
DrawGradient();
BuildGradientVector();
_performNeeded = true;
var oldMouseIn = _mouseIn;
_mouseIn = true;
Perform();
_mouseIn = oldMouseIn;
}
public void ReverseFFT(Signal signalIn, out Signal signal)
{
if (signalIn.Length == 0)
{
signal = new Signal(0);
return;
}
float[] values = new float[signalIn.Length + 2];
Buffer.BlockCopy(signalIn.Values, 0, values, 0, signalIn.Length);
Fourier.InverseReal(values, signalIn.Length);
signal = new Signal(values);
}
public static double[] padded_FFT(Complex[] complexSignal)
{
int N = complexSignal.Length;
Fourier.FFT(complexSignal, N, FourierDirection.Forward);
// get the result
double[] fft_real = new double[N];
for (int j = 0; j < N; j++)
{
fft_real[j] = complexSignal[j].Re;
}
return(fft_real);
}
private static void SyncLookupTableLength(int length)
{
Debug.Assert(length < 1024 * 10);
Debug.Assert(length >= 0);
if (length > _lookupTabletLength)
{
int level = (int)Math.Ceiling(Math.Log(length, 2));
Fourier.InitializeReverseBits(level);
Fourier.InitializeComplexRotations(level);
//_cFFTData = new Complex[ Math2.CeilingBase( length, 2 ) ];
//_cFFTDataF = new ComplexF[ Math2.CeilingBase( length, 2 ) ];
_lookupTabletLength = length;
}
}
public static List <double> AutoCorr(List <double> input, int n)
{
double avg = input.Average();
Complex[] inputAsComplex = input.Select(x => new Complex(x - avg, 0)).ToArray();
Fourier.Forward(inputAsComplex, FourierOptions.Matlab);
var conjugate = inputAsComplex.Select(Complex.Conjugate);
var S = conjugate.Select((x, i) => x * inputAsComplex[i]).ToArray();
Fourier.Inverse(S, FourierOptions.Matlab);
double first = S[0].Real;
return(S.Take(n).Select(x => x.Real / first).ToList());
}
private double[] PrepareVerticalFouirier(double[][] source, int line = 0)
{
double[] oneLine;
//take string x
oneLine = new double[source.Length];
for (int i = 0; i < source.Length; i++)
{
oneLine[i] = source[i][line];
}
//oneLine = Fourier.Derivative(oneLine);
//oneLine = Fourier.AutoCrossCorrelation(oneLine, oneLine);
oneLine = Fourier.FourierFunction(oneLine);
return(oneLine);
}
public void GenerateSignature()
{
int width = Sprite.DefaultSize;
int height = Sprite.DefaultSize;
if (this.Width > 1 || this.Height > 1)
{
width = Sprite.DefaultSize * 2;
height = Sprite.DefaultSize * 2;
}
Bitmap canvas = new Bitmap(width, height, PixelFormat.Format24bppRgb);
Graphics g = Graphics.FromImage(canvas);
// draw sprite
for (int l = 0; l < this.Layers; l++)
{
for (int h = 0; h < this.Height; ++h)
{
for (int w = 0; w < this.Width; ++w)
{
int index = w + h * this.Width + l * this.Width * this.Height;
Bitmap bitmap = ImageUtils.GetBitmap(this.SpriteList[index].GetRGBData(), PixelFormat.Format24bppRgb, Sprite.DefaultSize, Sprite.DefaultSize);
if (canvas.Width == Sprite.DefaultSize)
{
Rect.X = 0;
Rect.Y = 0;
Rect.Width = bitmap.Width;
Rect.Height = bitmap.Height;
}
else
{
Rect.X = Math.Max(Sprite.DefaultSize - w * Sprite.DefaultSize, 0);
Rect.Y = Math.Max(Sprite.DefaultSize - h * Sprite.DefaultSize, 0);
Rect.Width = bitmap.Width;
Rect.Height = bitmap.Height;
}
g.DrawImage(bitmap, Rect);
}
}
}
g.Save();
Bitmap ff2dBmp = Fourier.fft2dRGB(canvas, false);
this.SpriteSignature = ImageUtils.CalculateEuclideanDistance(ff2dBmp, 1);
}
protected override void _Initialize()
{
double factor = fftLength;
for (int i = 0; i < Channels; i++)
{
Fourier.Forward(filterFD[i]);
for (int j = 0; j < fftLength; j++)
{
filterFD[i][j] *= factor;
}
}
}
public override double[] Spectrum(double[] input, bool scale)
{
var data = ToComplex(input);
Fourier.Forward(data, FourierOptions.Default);
var spectrum = ComputeSpectrum(data);
Fourier.Inverse(data, FourierOptions.Default);
ToDouble(data, input);
return(spectrum);
}
public override double[] Spectrum(double[] input, bool scale)
{
var data = ToComplex(input);
Fourier.FFT(data, data.Length, FourierDirection.Forward);
var spectrum = ComputeSpectrum(data);
Fourier.FFT(data, data.Length, FourierDirection.Backward);
ToDouble(data, input);
return(spectrum);
}
public static double Estimate(double[] Samples, int Decimate, out double Phase)
{
Complex[] data = DecimateSignal(Samples, Decimate);
int N = data.Length;
Fourier.Forward(data);
// Zero the DC bin.
data[0] = 0.0;
double f = 0.0;
double max = 0.0;
Phase = 0.0;
// Find largest frequency in FFT.
for (int i = 1; i < N / 2 - 1; ++i)
{
double x;
Complex m = LogParabolaMax(data[i - 1], data[i], data[i + 1], out x);
if (m.Magnitude > max)
{
max = m.Magnitude;
f = i + x;
Phase = m.Phase;
}
}
// Check if this is a harmonic of another frequency (the fundamental frequency).
double f0 = f;
for (int h = 2; h < 5; ++h)
{
int i = (int)Math.Round(f / h);
if (i >= 1)
{
double x;
Complex m = LogParabolaMax(data[i - 1], data[i], data[i + 1], out x);
if (m.Magnitude * 5.0 > max)
{
f0 = f / h;
Phase = m.Phase;
}
}
}
return(f0);
}
public override void _Process(float delta)
{
long amountOfFramesPassed = (long)(stopwatch.Elapsed.TotalSeconds * sampleRate);
stopwatch.Restart();
//Delta time might not be entirely accurate. Using stopwatch instead.
for (int i = 0; i < amountOfFramesPassed; i++)
{
frameBuffer.Enqueue(samplesFrames[framePointer]);
framePointer = (framePointer + 1) % samplesFrames.LongLength;
if (frameBuffer.Count > MaxFFTSize)
{
frameBuffer.Dequeue();
}
}
if (frameBuffer.Count == 0)
{
return;
}
//Apply Hann window on the frames
var frameBufferArray = frameBuffer.ToArray();
for (int i = 0; i < frameBufferArray.Length; i++)
{
frameBufferArray[i] *= (float)hann[i];
}
//Convert frames to complex numbers
var framesComplex = FramesToComplex(frameBufferArray);
Complex[] samplesComplexLeft = framesComplex.Item1;
Complex[] samplesComplexRight = framesComplex.Item2;
//Do FFT
Fourier.Forward(samplesComplexLeft);
Fourier.Forward(samplesComplexRight);
//Convert to magnitudes
float[] freqMagnitudesLeft = Array.ConvertAll(samplesComplexLeft, x => (float)x.Magnitude);
float[] freqMagnitudesRight = Array.ConvertAll(samplesComplexRight, x => (float)x.Magnitude);
//Convert to cubes
GetNode <Meshes>("Meshes").PlaceCubes(freqMagnitudesLeft, freqMagnitudesRight, sampleRate);
}
public void CalculatePuls(List <double> dataList)
{
foreach (var value in dataList)
{
analysisList.Add(value);
}
if (analysisList.Count == 6 * _daqDTO.SampleRate)
{
Complex[] complexAnalysisListWithoutWindow = new Complex[6 * _daqDTO.SampleRate];
for (int i = 0; i < analysisList.Count; i++)
{
complexAnalysisListWithoutWindow[i] = new Complex(analysisList[i], 0);
}
Complex[] complexAnalysisListWithWindow = new Complex[6 * _daqDTO.SampleRate];
double[] hammingWindow = MathNet.Numerics.Window.Hamming(complexAnalysisListWithWindow.Length);
for (int i = 0; i < complexAnalysisListWithoutWindow.Length; i++)
{
complexAnalysisListWithWindow[i] = hammingWindow[i] * complexAnalysisListWithoutWindow[i];
}
Fourier.Forward(complexAnalysisListWithWindow, FourierOptions.NoScaling);
double[] magnitudes = new double[complexAnalysisListWithWindow.Length / 2]; //vi kigger kun på den første halvdel af frekvensspekteret fordi efter nyquist frekvensen gentager spekteret sig.
for (int i = 2; i < complexAnalysisListWithWindow.Length / 2; i++)
{
magnitudes[i] = complexAnalysisListWithWindow[i].Magnitude;
}
int maxIndex = 0;
for (int i = 0; i < magnitudes.Length; i++)
{
if (magnitudes[i] == magnitudes.Max())
{
maxIndex = i;
}
}
double frequenceForMaxMagnitude = maxIndex * 1000.0 / complexAnalysisListWithWindow.Length;
double bpm = 60 * frequenceForMaxMagnitude;
_puls = bpm;
Notify();
analysisList.Clear();
}
}
public static double[] padded_IFFT(double[] signal)
{
int N = signal.Length;
Complex[] complexSignal = FFTUtils.DoubleToComplex(signal);
Fourier.FFT(complexSignal, N, FourierDirection.Backward);
// get the result
double[] fft_real = new double[N];
for (int j = 0; j < N; j++)
{
fft_real[j] = complexSignal[j].Re;
}
return(fft_real);
}
public override void Load()
{
if (Fetched)
{
return;
}
var images = DoFetchImages(FileNames);
_fft = Fourier.FFT2(Images[0], false);
ViewColumns = 9;
ViewRows = 9;
Images = images;
Rearrange(0, 0, 300, 150, 9);
}
public FrequencyChart AnalyzeSound(Complex[] sound, int offset)
{
var sample = new Complex[window.Length];
Array.Copy(sound, offset, sample, 0, window.Length);
Fourier.Radix2Forward(sample, FourierOptions.Default);
var chart = new FrequencyChart(
sample.Select(k => k.Magnitude * 2 / (sample.Length))
.Zip(frqs, (a, f) => new FrequencyPair(f, a))
.Where(k => k.Frequency > 0)
.ToArray());
return(chart);
}
private static double[] Analyse(double[] sliver)
{
var extra = sliver.Length - FFT_SIZE;
var samples = sliver.Skip(extra).Select(sample => new Complex(sample, 0)).ToArray();
Fourier.Forward(samples);
var results = samples.Select(result => result.Magnitude).Take(FFT_SIZE / 2).ToArray();
// The first result always looks massive and skews everything else so force it to 0.
// TODO: figure out why
// - something to do with the ffmpeg conversion from .mp3 to .pcm ?
// - as comparison, FFT of generated sine wave looks fine
// results[0] = 0;
return(results);
}
private void DoApply(UnmanagedImage image, UnmanagedImage output)
{
var fimg = Fourier.FFT2(image);
if (Width != fimg.Width ||
Height != fimg.Height)
{
throw new DimensionMismatchException();
}
fimg.C0.MultiplyWith(C0);
fimg.C1.MultiplyWith(C1);
fimg.C2.MultiplyWith(C2);
output.Draw(fimg.InverseFFT2(false));
}
private void CreateSpectrum(ref float[] data)
{
for (int i = 0; i < data.Length; i++)
{
_complexBuffer[i] = new Complex32(data[i], 0);
}
Fourier.Forward(_complexBuffer, FourierOptions.NoScaling);
for (int i = 0; i < _spectrum.Length; i++)
{
Complex32 fourierData = _complexBuffer[i];
_spectrum[i] = (float)Math.Sqrt(fourierData.Real * fourierData.Real) + (fourierData.Imaginary * fourierData.Imaginary);
}
}
public static void BenchFourier()
{
Setup();
FourierStruct t = new Fourier();
t.adjust = 0;
foreach (var iteration in Benchmark.Iterations)
{
using (iteration.StartMeasurement())
{
for (int i = 0; i < FourierIterations; i++)
{
t.Run();
}
}
}
}