public void FftSingleReal(
[Values(1024, 4096, 8192, 16384, 65536, 262144, 1048576)] int numSamples)
{
int half = numSamples >> 1;
double[] dataEven = new double[numSamples];
for (int i = 0; i < numSamples; i++)
{
double z = (double)(i - half) / half;
dataEven[i] = 1.0 / ((z * z) + 1.0);
}
double[] evenReal, evenImag;
_fft.TransformForward(dataEven, out evenReal, out evenImag);
// round trip check
double[] dataEven2;
_fft.TransformBackward(evenReal, evenImag, out dataEven2);
// Compare with original samples
for (int i = 0; i < numSamples; i += 2)
{
Assert.That(dataEven2[i], NumericIs.AlmostEqualTo(dataEven[i], 1e-5), i.ToString());
}
}
public void Real_TwoReal_Inverse()
{
int numSamples = 32;
int half = numSamples >> 1;
double[] dataEven = new double[numSamples];
double[] dataOdd = new double[numSamples];
for (int i = 0; i < numSamples; i++)
{
double z = (double)(i - half) / half;
dataEven[i] = 1.0 / (z * z + 1.0);
dataOdd[i] = z / (z * z + 1.0);
}
dataOdd[0] = 0.0; // periodic continuation; force odd
RealTestTimeEven(dataEven);
RealTestTimeOdd(dataOdd);
double[] evenReal, evenImag, oddReal, oddImag;
// Forward Transform
rft.Convention = TransformationConvention.Default;
rft.TransformForward(dataEven, dataOdd,
out evenReal, out evenImag, out oddReal, out oddImag);
// Backward Transform
double[] dataEven2, dataOdd2;
rft.TransformBackward(evenReal, evenImag, oddReal, oddImag,
out dataEven2, out dataOdd2);
// Compare with original samples
for (int i = 0; i < numSamples; i += 2)
{
Assert.AreEqual(dataEven[i], dataEven2[i], 0.00001, "Inv: Even: " + i.ToString());
Assert.AreEqual(dataOdd[i], dataOdd2[i], 0.00001, "Inv: Odd: " + i.ToString());
}
}
private double[] IFFT(Complex complex)
{
double[] result;
rft.TransformBackward(complex.Reals, complex.Imags, out result);
return(result);
}