org.shared.fft

Class FftOps

java.lang.Object

org.shared.fft.FftOps

public class FftOps
extends Object

A class of mixed-radix FFT operations in support of JavaFftService.

Method Summary

Methods

Modifier and Type	Method and Description
protected static int[]	createFactors(int num) Creates a prime factorization and stride modifiers array.
protected static double[]	createTwiddles(int n, int direction) Creates an array of twiddle factors.
protected static void	fft(double[] src, int srcOffset, double[] dst, int dstOffset, double[] scratch, int[] factors, int factorIndexCurrent, double[] twiddles, int size, int stride, int strideCurrent) The main mixed-radix FFT procedure.
protected static void	fft(double[] dst, int dstOffsetCurrent, double[] scratch, int p, int n, double[] twiddles, int size, int strideCurrent) A recursive FFT subroutine for a specific radix.
static void	fft(int direction, int[] dims, double[] in, double[] out) An FFT operation in support of JavaFftService.fft(int[], double[], double[]).

Methods inherited from class java.lang.Object

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

Method Detail

fft

public static final void fft(int direction,
       int[] dims,
       double[] in,
       double[] out)

An FFT operation in support of JavaFftService.fft(int[], double[], double[]). Very slow and unoptimized; for demonstration purposes only.

Parameters:

direction - the transform direction.

dims - the array dimensions.

in - the in array.

out - the out array.

createFactors

protected static final int[] createFactors(int num)

Creates a prime factorization and stride modifiers array.

createTwiddles

protected static final double[] createTwiddles(int n,
                      int direction)

Creates an array of twiddle factors.

fft

protected static final void fft(double[] src,
       int srcOffset,
       double[] dst,
       int dstOffset,
       double[] scratch,
       int[] factors,
       int factorIndexCurrent,
       double[] twiddles,
       int size,
       int stride,
       int strideCurrent)

The main mixed-radix FFT procedure.

fft

protected static final void fft(double[] dst,
       int dstOffsetCurrent,
       double[] scratch,
       int p,
       int n,
       double[] twiddles,
       int size,
       int strideCurrent)

A recursive FFT subroutine for a specific radix.