Package ffx.numerics.fft

Class Real

java.lang.Object

ffx.numerics.fft.Real

public class Real
extends Object

Compute the FFT of real, double precision data of arbitrary length n using a Complex transform.

Since:

1.0

Author:

Michal J. Schnieders
Derived from:
Bruce R. Miller bruce.miller@nist.gov
Contribution of the National Institute of Standards and Technology, not subject to copyright.
Derived from:
GSL (Gnu Scientific Library) FFT Code by Brian Gough bjg@vvv.lanl.gov

See Also:

• • Henrik V. Sorenson, Douglas L. Jones, Michael T. Heideman, and C. Sidney Burrus. Real-valued fast fourier fft algorithms. IEEE Transactions on Acoustics, Speech, and Signal Processing, ASSP-35(6):849–863, 1987.
  • J. W. Cooley and J. W. Tukey, Mathematics of Computation 19 (90), 297 (1965)
  • FFT at Wikipedia

Constructor Summary

Constructors

Constructor	Description
Real(int n)	Constructs a Complex FFT of length (n / 2) for real data of length n.

Method Summary

Modifier and Type	Method	Description
void	fft(double[] data, int offset)	fft
void	ifft(double[] data, int offset)	ifft
void	inverse(double[] data, int offset)	inverse

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Real

public Real(int n)

Constructs a Complex FFT of length (n / 2) for real data of length n.

Parameters:

n - the length of the real data.

Method Details

fft

public void fft(double[] data,
 int offset)

fft

Parameters:

data - Input data.

offset - Offset to the beginning of the data.

ifft

public void ifft(double[] data,
 int offset)

ifft

Parameters:

data - Input data.

offset - Offset to the beginning of the data.

inverse

public void inverse(double[] data,
 int offset)

inverse

Parameters:

data - Input data.

offset - Offset to the beginning of the data.