using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using UnitTestSharp;
using Azimuth.DenseLinearAlgebra;
using Azimuth.FastFourierTransform;

namespace Azimuth.UnitTests.FastFourierTransform
{
    public class FastFourierTransform : TestFixture
    {
        public void x10000000()
        {
            var real = new DenseVector(new Scalar[] { 1, 0, 0, 0, 0, 0, 0, 0, });
            var imag = new DenseVector(new Scalar[] { 0, 0, 0, 0, 0, 0, 0, 0, });

            var fft = new FFT(3);
            fft.Transform(ref real, ref imag, 3);

            var expectedReal = new DenseVector(new Scalar[] 
            {
                1, 1, 1, 1,
                1, 1, 1, 1,
            });

            var expectedImag = new DenseVector(new Scalar[] 
            {
                0, 0, 0, 0,
                0, 0, 0, 0,
            });

            CheckEqual(expectedReal, real);
            CheckEqual(expectedImag, imag);
        }

        public void x01234567()
        {
            var real = new DenseVector(new Scalar[] { 0, 1, 2, 3, 4, 5, 6, 7, });
            var imag = new DenseVector(new Scalar[] { 0, 0, 0, 0, 0, 0, 0, 0, });

            var fft = new FFT(3);
            fft.Transform(ref real, ref imag, 3);

            var sqr2 = Math.Sqrt(2);
            var expectedReal = new DenseVector(new Scalar[] 
            {
                28, -4, -4, -4, -4, -4, -4, -4,
            });

            var expectedImag = new DenseVector(new Scalar[] 
            {
                0, -4 * (1 + sqr2), -4, -4 * (sqr2 - 1), 0, 4*(sqr2 - 1), 4, 4 * (1 + sqr2),
            });

            CheckEqual(expectedReal, real);
            CheckEqual(expectedImag, imag);
        }

        public void x16()
        {
            var real = new DenseVector(new Scalar[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, });
            var imag = new DenseVector(new Scalar[] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  0,  0,  0,  0,  0,  0, });

            var fft = new FFT(4);
            fft.Transform(ref real, ref imag, 4);

            var sqr2 = Math.Sqrt(2);
            var expectedReal = new DenseVector(new Scalar[] 
            {
                120, -8, -8, -8,
                -8, -8, -8, -8,
                -8, -8, -8, -8, 
                -8, -8, -8, -8,
            });

            var expectedImag = new DenseVector(new Scalar[] 
            {
                0,
                -40.218715937006785,
                -8 * (1 + sqr2),
                -11.972846101323906,
                -8,
                -5.345429103354382,
                -3.3137084989847576,
                -1.5912989390372658,
                0,
                1.5912989390372587,
                3.313708498984756,
                5.3454291033543875,
                8.000000000000002,
                11.972846101323908,
                8 * (1 + sqr2),
                40.218715937006785,
            });

            CheckEqual(expectedReal, real);
            CheckEqual(expectedImag, imag);
        }
    }
}