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

namespace Azimuth.UnitTests.SparseLinearAlgebra
{
    public class CirculantMatrixTests : UnitTestSharp.TestFixture
    {
        public void Basic_x8()
        {
            DenseVector circulant = new Scalar[] { 0, 1, 2, 3, 4, 5, 6, 7, };
            DenseVector b = new Scalar[] { 1, 1, 1, 1, 2, 2, 2, 2 };

            var C = new CirculantMatrix(circulant);

            C.SolveSystem(b, ref b);

            var expected = new DenseVector(new Scalar[]
            {
                  0.0535714285714286,
                  0.0535714285714286,
                  0.0535714285714286,
                  0.1785714285714286,
                  0.0535714285714286,
                  0.0535714285714286,
                  0.0535714285714286,
                  -0.0714285714285715,
            });

            CheckEqual(expected, b);
        }

        public void NonPowerOf2()
        {
            var circulant = new DenseVector(new Scalar[] { 0, 1, 2, 3, 4, });
            var b = new DenseVector(new Scalar[] { 1, 1, 1, 1, 2, });

            var C = new CirculantMatrix(circulant);

            C.SolveSystem(b, ref b);

            var expected = new DenseVector(new Scalar[] 
            {
               .12, .12, .12, .32, -0.08,
            });

            CheckEqual(expected, b);
        }

        public void SizeMismatch()
        {
            var circulant = new DenseVector(new Scalar[] { 0, 1, 2, 3, });
            var b = new DenseVector(new Scalar[] { 1, 1, 1, });
            var x = new DenseVector(4);

            var C = new CirculantMatrix(circulant);

            CheckThrow(typeof(Exception));
            C.SolveSystem(b, ref x);
        }
    }
}