/// <summary>
/// Inplace Forward Transformation in one dimension. Size must be Power of Two.
/// </summary>
/// <param name="samplePairs">Complex samples (even = real, odd = imaginary). Length must be a power of two.</param>
public void TransformForward(double[] samplePairs)
{
if (Fn.CeilingToPowerOf2(samplePairs.Length) != samplePairs.Length)
{
throw new ArgumentException(Resources.ArgumentPowerOfTwo, "samplePairs");
}
_fft.DiscreteFourierTransform(samplePairs, true, _convention);
}
/// <summary>
/// Outplace Forward Transformation in one dimension for two vectors with the same length.
/// Size must be Power of Two.
/// </summary>
/// <param name="samples1">Real samples. Length must be a power of two.</param>
/// <param name="samples2">Real samples. Length must be a power of two.</param>
public void TransformForward(double[] samples1, double[] samples2,
out double[] fftReal1, out double[] fftImag1, out double[] fftReal2, out double[] fftImag2)
{
if (samples1.Length != samples2.Length)
{
throw new ArgumentException(Resources.ArgumentVectorsSameLengths, "samples2");
}
if (Fn.CeilingToPowerOf2(samples1.Length) != samples1.Length)
{
throw new ArgumentException(Resources.ArgumentPowerOfTwo, "samples1");
}
int numSamples = samples1.Length;
int length = numSamples << 1;
// Pack together to one complex vector
double[] complex = new double[length];
for (int i = 0, j = 0; i < numSamples; i++, j += 2)
{
complex[j] = samples1[i];
complex[j + 1] = samples2[i];
}
// Transform complex vector
_fft.DiscreteFourierTransform(complex, true, _convention);
// Reconstruct data for the two vectors by using symmetries
fftReal1 = new double[numSamples];
fftImag1 = new double[numSamples];
fftReal2 = new double[numSamples];
fftImag2 = new double[numSamples];
double h1r, h2i, h2r, h1i;
fftReal1[0] = complex[0];
fftReal2[0] = complex[1];
fftImag1[0] = fftImag2[0] = 0d;
for (int i = 1, j = 2; j <= numSamples; i++, j += 2)
{
h1r = 0.5 * (complex[j] + complex[length - j]);
h1i = 0.5 * (complex[j + 1] - complex[length + 1 - j]);
h2r = 0.5 * (complex[j + 1] + complex[length + 1 - j]);
h2i = -0.5 * (complex[j] - complex[length - j]);
fftReal1[i] = h1r;
fftImag1[i] = h1i;
fftReal1[numSamples - i] = h1r;
fftImag1[numSamples - i] = -h1i;
fftReal2[i] = h2r;
fftImag2[i] = h2i;
fftReal2[numSamples - i] = h2r;
fftImag2[numSamples - i] = -h2i;
}
}
TransformForward(
double[] samples1,
double[] samples2,
out double[] fftReal1,
out double[] fftImag1,
out double[] fftReal2,
out double[] fftImag2)
{
if (samples1.Length != samples2.Length)
{
throw new ArgumentException(Properties.LocalStrings.ArgumentVectorsSameLengths, "samples2");
}
if (Fn.CeilingToPowerOf2(samples1.Length) != samples1.Length)
{
throw new ArgumentException(Properties.LocalStrings.ArgumentPowerOfTwo, "samples1");
}
int numSamples = samples1.Length;
int length = numSamples << 1;
/* Pack together to one complex vector */
double[] complex = new double[length];
for (int i = 0, j = 0; i < numSamples; i++, j += 2)
{
complex[j] = samples1[i];
complex[j + 1] = samples2[i];
}
/* Transform complex vector */
_fft.DiscreteFourierTransform(complex, true, _convention);
/* Reconstruct data for the two vectors by using symmetries */
fftReal1 = new double[numSamples];
fftImag1 = new double[numSamples];
fftReal2 = new double[numSamples];
fftImag2 = new double[numSamples];
fftReal1[0] = complex[0];
fftReal2[0] = complex[1];
fftImag1[0] = fftImag2[0] = 0d;
for (int i = 1, j = 2; j <= numSamples; i++, j += 2)
{
double h1Real = 0.5 * (complex[j] + complex[length - j]);
double h1Imag = 0.5 * (complex[j + 1] - complex[length + 1 - j]);
double h2Real = 0.5 * (complex[j + 1] + complex[length + 1 - j]);
double h2Imag = -0.5 * (complex[j] - complex[length - j]);
fftReal1[i] = h1Real;
fftImag1[i] = h1Imag;
fftReal1[numSamples - i] = h1Real;
fftImag1[numSamples - i] = -h1Imag;
fftReal2[i] = h2Real;
fftImag2[i] = h2Imag;
fftReal2[numSamples - i] = h2Real;
fftImag2[numSamples - i] = -h2Imag;
}
}
