public void TestRealTransform()
{
IDFT realFourierTransform = new RealFastFourierTransform();
FrequencyDomain realFormatResult;
List <double> recreatedSignal;
int sampleRate = 1000; // hz
List <double> timePoints = new List <double>(2 * sampleRate);
for (double timePointVal = 0; timePointVal < 2.0; timePointVal += (1.0 / sampleRate))
{
timePoints.Add(timePointVal);
}
List <double> signal = new List <double>(timePoints.Count);
foreach (double timePointVal in timePoints)
{
double signalValue = (2.5 * Math.Sin(2 * Math.PI * 4 * timePointVal)) + (1.5 * Math.Sin(2 * Math.PI * 6.5 * timePointVal));
signal.Add(signalValue);
}
realFormatResult = realFourierTransform.Transform(signal.GetRange(0, 256), sampleRate);
recreatedSignal = realFourierTransform.Synthesize(realFormatResult);
Assert.IsNotNull(realFormatResult);
Assert.IsNotNull(recreatedSignal);
for (int idx = 0; idx < recreatedSignal.Count; idx++)
{
Assert.IsTrue((Math.Abs(recreatedSignal[idx] - signal[idx]) < MaxDifference));
}
}
static void Main(string[] args)
{
// ISignalGenerator sinusoid = new Sinusoid();
// Sample sinusoidSamp = new Sample(1000, 1, 200, sinusoid);
// List<double> signal = sinusoidSamp.GetNextSamplesForTimeSlice(64);
// IDFT transform = new FastFourierTransform();
// FrequencyDomain frequencyDomain = transform.Transform(signal);
// List<double> synthesis = transform.Synthesize(frequencyDomain);
try
{
StreamReader input = new StreamReader(args[0]);
List <double> signal = new List <double>(64);
while (input.Peek() > 0)
{
double value;
if (Double.TryParse(input.ReadLine(), out value))
{
signal.Add(value);
}
}
IDFT transform = new RealFastFourierTransform();
FrequencyDomain frequencyDomain = transform.Transform(signal);
//List<double> synthesis = transform.Synthesize(frequencyDomain);
FileStream output = new FileStream("FourierTransformResults.csv", FileMode.Create);
if (output.CanWrite)
{
StreamWriter writer = new StreamWriter(output);
// Write header row
writer.WriteLine("Index, Signal, Synthesis, Real, Imaginary");
for (int idx = 0; idx < signal.Count; idx++)
{
double sampleVal = signal[idx];
double synthVal = 0.0f;
writer.WriteLine(idx + "," + sampleVal + "," + synthVal + "," + frequencyDomain.RealComponent[idx] + "," + frequencyDomain.ImaginaryComponent[idx]);
}
writer.Close();
}
output.Close();
} catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
