package com.imsl.test.example.math;

import com.imsl.math.*;

/**
 * <p>
 * Finds the Fourier coefficients of a complex
 * sequence.</p>
 *
 * The Fourier coefficients of a complex periodic sequence are computed. Then
 * the coefficients are used to try to reproduce the periodic sequence.
 *
 * @see <a href="ComplexFFTEx1.java">Code</a>
 * @see <a href="doc-files/ComplexFFTEx1.out">Output</a>
 */

public class ComplexFFTEx1 {

    public static void main(String args[]) {
        Complex x[] = {
            new Complex(1, 8),
            new Complex(2, 7),
            new Complex(3, 6),
            new Complex(4, 5),
            new Complex(5, 4),
            new Complex(6, 3),
            new Complex(7, 2),
            new Complex(8, 1)
        };
        ComplexFFT fft = new ComplexFFT(x.length);

        Complex y[] = fft.forward(x);
        Complex z[] = fft.backward(y);
        for (int i = 0; i < x.length; i++) {
            z[i] = Complex.divide(z[i], x.length);
        }

        new PrintMatrix("x").print(x);
        new PrintMatrix("y").print(y);
        new PrintMatrix("z").print(z);
    }
}