public static void ForwardTransform(FFTW.DoubleArray input, FFTW.ComplexArray output)
{
IntPtr plan = FFTW.dft_r2c_1d(input.Length, input.Handle, output.Handle, Flags.Estimate);
//FFTW.print_plan(plan);
FFTW.execute(plan);
FFTW.destroy_plan(plan);
}
public static void BackwardTransform(FFTW.ComplexArray input, FFTW.DoubleArray output)
{
// TODO: make sure to use input.Length and not the output.Length ?!
IntPtr plan = FFTW.dft_c2r_1d(input.Length, input.Handle, output.Handle, Flags.Estimate);
//FFTW.print_plan(plan);
FFTW.execute(plan);
FFTW.destroy_plan(plan);
}
public DoubleArray(IEnumerable <double> data, Func <int, int, double> window)
{
Length = data.Count();
Handle = FFTW.malloc(Marshal.SizeOf(typeof(double)) * Length);
double[] buffer = new double[Length];
for (int i = 0; i < Length; i++)
{
buffer[i] = data.ElementAt(i) * window(i, Length);
}
Marshal.Copy(buffer, 0, Handle, Length);
}
/// <summary>
/// Initialize a complex array using real and imaginary data
/// that has the length of N/2+1.
/// </summary>
/// <param name="realData">real data</param>
/// <param name="imagData">imaginary data</param>
public ComplexArray(double[] realData, double[] imagData)
{
if (realData.Length != imagData.Length)
{
throw new ArgumentException(
"data length for real data [" + realData.Length + "] is not the same as imaginary data [" + imagData.Length + "]");
}
// make sure to have room for both arrays
int length = realData.Length * 2;
double[] buffer = new double[length];
for (int i = 0; i < realData.Length; i++)
{
buffer[2 * i] = realData[i];
buffer[2 * i + 1] = imagData[i];
}
Handle = FFTW.malloc(Marshal.SizeOf(typeof(double)) * length);
Marshal.Copy(buffer, 0, Handle, length);
// Update length to reflect a N/2+1 input
Length = (realData.Length - 1) * 2;
}
public DoubleArray(double[] data)
{
Length = data.Length;
Handle = FFTW.malloc(Marshal.SizeOf(typeof(double)) * Length);
Marshal.Copy(data, 0, Handle, Length);
}
public DoubleArray(int length)
{
Length = length;
Handle = FFTW.malloc(Marshal.SizeOf(typeof(double)) * Length);
}
