using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Azimuth;

namespace Azimuth.UnitTests
{
    public class BesselFunctionTests : UnitTestSharp.TestFixture
    {
        public void AllIntegralOrders_SmallX()
        {
            var evalOut = new DenseVector(20);
            BesselFunction.J_AllIntegralOrders(0.623, ref evalOut);

            DenseVector expected = new Scalar[]
            {
                9.05296340367585e-001,
                2.96629664754228e-001,
                4.69658257776098e-002,
                4.91656816782477e-003,
                3.84750477524405e-004,
                2.40479159557114e-005,
                1.25138372296984e-006,
                5.57833631298634e-008,
                2.17499904956167e-009,
                7.53604543848024e-011,
                2.34955224642239e-012,
                6.65840236214234e-014,
                1.72948659737250e-015,
                4.14632757509882e-017,
                9.22984530708138e-019,
                1.91750673548736e-020,
                3.73447857209680e-022,
                6.84505397028993e-024,
                1.18491088647308e-025,
                1.94312650470616e-027,
            };

            CheckEqual(expected, evalOut);
        }

        public void AllIntegralOrders_SmallX_Negative()
        {
            var evalOut = new DenseVector(20);
            BesselFunction.J_AllIntegralOrders(-0.623, ref evalOut);

            DenseVector expected = new Scalar[]
            {
                9.05296340367585e-001,
                -2.96629664754228e-001,
                4.69658257776098e-002,
                -4.91656816782477e-003,
                3.84750477524405e-004,
                -2.40479159557114e-005,
                1.25138372296984e-006,
                -5.57833631298634e-008,
                2.17499904956167e-009,
                -7.53604543848024e-011,
                2.34955224642239e-012,
                -6.65840236214234e-014,
                1.72948659737250e-015,
                -4.14632757509882e-017,
                9.22984530708138e-019,
                -1.91750673548736e-020,
                3.73447857209680e-022,
                -6.84505397028993e-024,
                1.18491088647308e-025,
                -1.94312650470616e-027,
            };

            CheckEqual(expected, evalOut);
        }

        public void AllIntegralOrders_LargeX_n3()
        {
            var evalOut = new DenseVector(3);
            BesselFunction.J_AllIntegralOrders(300, ref evalOut);

            DenseVector expected = new Scalar[]
            {
                -0.0332985548763057,
                -0.0318874313774999,
                0.0330859720004557,
            };

            CheckEqual(expected, evalOut);
        }

        public void AllIntegralOrders_LargeX_n20()
        {
            var evalOut = new DenseVector(20);
            BesselFunction.J_AllIntegralOrders(300, ref evalOut);

            DenseVector expected = new Scalar[]
            {
                -0.0332985548763057,
                -0.0318874313774999,
                0.0330859720004557,
                0.0323285776708394,
                -0.0324394004470389,
                -0.0331936283494271,
                0.0313329461687246,
                0.0344469461961760,
                -0.0297254220129031,
                -0.0360323020368642,
                0.0275634838906912,
                0.0378698676295770,
                -0.0247863602645223,
                -0.0398527764507387,
                0.0213324529721249,
                0.0418438053948037,
                -0.0171480724326445,
                -0.0436729331209525,
                0.0121984733456032,
                0.0451367499224249,
            };

            CheckEqual(expected, evalOut);
        }

        public void AllIntegralOrders_LargeX_n20_negative()
        {
            var evalOut = new DenseVector(20);
            BesselFunction.J_AllIntegralOrders(-300, ref evalOut);

            DenseVector expected = new Scalar[]
            {
                -0.0332985548763057,
                -0.0318874313774999,
                 0.0330859720004557,
                 0.0323285776708394,
                -0.0324394004470389,
                -0.0331936283494271,
                 0.0313329461687246,
                 0.0344469461961760,
                -0.0297254220129031,
                -0.0360323020368642,
                 0.0275634838906912,
                 0.0378698676295770,
                -0.0247863602645223,
                -0.0398527764507387,
                 0.0213324529721249,
                 0.0418438053948037,
                -0.0171480724326445,
                -0.0436729331209525,
                 0.0121984733456032,
                 0.0451367499224249,
            };

            CheckEqual(expected, evalOut);
        }

        public void AllIntegralOrders_0()
        {
            var evalOut = new DenseVector(20);
            BesselFunction.J_AllIntegralOrders(0, ref evalOut);

            DenseVector expected = new Scalar[]
            {
                1, 0, 0, 0, 0,
                0, 0, 0, 0, 0,
                0, 0, 0, 0, 0,
                0, 0, 0, 0, 0,
            };

            CheckEqual(expected, evalOut);
        }

        public void AllIntegralOrders_Epsilon()
        {
            var w = 0.00000000000000006352163501508065;

            var evalOut = new DenseVector(256);
            BesselFunction.J_AllIntegralOrders(w, ref evalOut);

            DenseVector expected = new DenseVector(256);
            expected[0] = 1;

            CheckEqual(expected, evalOut);
        }

        public void J0()
        {
            var evaluationPoints = new Scalar[] 
            {
                0, .2, .1, 30, 4, 9, 8, 1000, 300
            };

            var expectedValues = new Scalar[]
            {
                1.0000000000000000,
                0.9900249722395764,
                0.9975015620660401,
                -0.0863679835810402,
                -0.3971498098638475,
                -0.0903336111828763,
                0.1716508071375539,
                0.0247866861524202,
                -0.0332985548763057,
            };

            var actualValues = evaluationPoints.Select(x => BesselFunction.J0(x));

            CheckEqual(expectedValues, actualValues);
        }

        public void J1()
        {
            var evaluationPoints = new Scalar[] 
            {
                0, .2, .1, 30, 4, 9, 8, 1000, 300,
            };

            var expectedValues = new Scalar[]
            {
                0.000000000000000,
                0.099500832639236,
                0.049937526036242,
                -0.118751062616623,
                -0.066043328023549,
                0.245311786573325,
                0.234636346853915,
                0.004728311907090,
                -0.0318874313774999
            };

            var actualValues = evaluationPoints.Select(x => BesselFunction.J1(x));

            CheckEqual(expectedValues, actualValues);
        }
    }
}