samer@0: /*
samer@0:  *	Copyright (c) 2000, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS iS and WITHOUT ANY WARRANTY;
samer@0:  *	without even the implied warranty of MERCHANTABILITY or
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package samer.units;
samer@0: 
samer@0: import samer.core.*;
samer@0: import samer.maths.*;
samer@0: import samer.tools.*;
samer@0: import samer.functions.*;
samer@0: 
samer@0: /**
samer@0: 	Manages a fourier transform from a given Vec into
samer@0: 	another vector. Can create tasks appropriate for
samer@0: 	a power spectrum or an arbitrary function of a
samer@0: 	power spectrum.
samer@0:   */
samer@0: 
samer@0: public class FFTVector extends FFT implements Task
samer@0: {
samer@0: 	Vec			in;
samer@0: 
samer@0: 	public FFTVector(Vec in) throws Exception { this(in.size()); setInput(in); }
samer@0: 	public FFTVector(int N) throws Exception
samer@0: 	{
samer@0: 		super(N);
samer@0: 
samer@0: 		// setup window function
samer@0: 		String window = Shell.getString("ft.window","hamming");
samer@0: 		if (window.equals("rectangular")) setWindow(new Constant(1.0));
samer@0: 		else if (window.equals("hanning")) setWindow(new Hanning());
samer@0: 		else setWindow(new Hamming());
samer@0: 	}
samer@0: 
samer@0: 	public void   setInput(Vec in) { this.in = in; }
samer@0: 	public String toString() { return "FT("+in+")"; }
samer@0: 	public Vec    real() { return new Vec.ForArray(real); }
samer@0: 	public Vec    imag() { return new Vec.ForArray(imag); }
samer@0: 
samer@0: 	public void starting() {}
samer@0: 	public void stopping() {}
samer@0: 	public void run() { input(in.iterator()); calculate(); }
samer@0: 	public void dispose() {}
samer@0: 
samer@0: 	public Task calcTask() {
samer@0: 		if (in.array()!=null) {
samer@0: 			return new AnonymousTask() {
samer@0: 				double [] b=in.array();
samer@0: 				public void run() throws Exception {
samer@0: 					input(b); calculate();
samer@0: 				}
samer@0: 				public String toString() { return FFTVector.this.toString()+": compute"; }
samer@0: 			};
samer@0: 		} else return this;
samer@0: 	}
samer@0: 
samer@0: 	public Task getPower(final VVector A)
samer@0: 	{
samer@0: 		final double [] a=A.array();
samer@0: 		return new AnonymousTask() {
samer@0: 			public void run() throws Exception	{
samer@0: 				outputPower(a); A.changed();
samer@0: 			}
samer@0: 			public String toString() { return FFTVector.this.toString()+":power->"+A; }
samer@0: 		};
samer@0: 	}
samer@0: 
samer@0: 	public Task getFnPower(final Function f, final VVector A)
samer@0: 	{
samer@0: 		final double [] a=A.array();
samer@0: 		return new AnonymousTask() {
samer@0: 			public void run() throws Exception {
samer@0: 				outputPower(a); f.apply(a);
samer@0: 				A.changed();
samer@0: 			}
samer@0: 			public void dispose() { f.dispose(); super.dispose(); }
samer@0: 			public String toString() {
samer@0: 				return FFTVector.this.toString()+":"+f.format("power")+"->"+A;
samer@0: 			}
samer@0: 		};
samer@0: 	}
samer@0: 
samer@0: 	public Task getLinearFT(final VVector A)
samer@0: 	{
samer@0: 		return new AnonymousTask() {
samer@0: 			double[] a=A.array();
samer@0: 
samer@0: 			public void run() throws Exception
samer@0: 			{
samer@0: 				int i=1,j=1;
samer@0: 				a[0]=real[0];
samer@0: 				for (; i<N/2; i++) {
samer@0: 					a[j++] = real[i];
samer@0: 					a[j++] = imag[i];
samer@0: 				}
samer@0: 				a[j]=real[i];  // i=N/2, j=N-1 (I hope)
samer@0: 				A.changed();
samer@0: 			}
samer@0: 			public String toString() { return FFTVector.this.toString()+"->"+A; }
samer@0: 		};
samer@0: 	}
samer@0: }
samer@0: