// <copyright file="SparseVectorTest.cs" company="Math.NET">
// Math.NET Numerics, part of the Math.NET Project
// http://numerics.mathdotnet.com
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// http://mathnetnumerics.codeplex.com
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namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Complex32
{
    using System;
    using System.Collections.Generic;
    using LinearAlgebra.Complex32;
    using LinearAlgebra.Generic;
    using NUnit.Framework;
    using Complex32 = Numerics.Complex32;

    /// <summary>
    /// Sparse vector tests.
    /// </summary>
    public class SparseVectorTest : VectorTests
    {
        /// <summary>
        /// Creates a new instance of the Vector class.
        /// </summary>
        /// <param name="size">The size of the <strong>Vector</strong> to construct.</param>
        /// <returns>The new <c>Vector</c>.</returns>
        protected override Vector<Complex32> CreateVector(int size)
        {
            return new SparseVector(size);
        }

        /// <summary>
        /// Creates a new instance of the Vector class.
        /// </summary>
        /// <param name="data">The array to create this vector from.</param>
        /// <returns>The new <c>Vector</c>.</returns>
        protected override Vector<Complex32> CreateVector(IList<Complex32> data)
        {
            var vector = new SparseVector(data.Count);
            for (var index = 0; index < data.Count; index++)
            {
                vector[index] = data[index];
            }

            return vector;
        }

        /// <summary>
        /// Can create a sparse vector form array.
        /// </summary>
        [Test]
        public void CanCreateSparseVectorFromArray()
        {
            var data = new Complex32[Data.Length];
            Array.Copy(Data, data, Data.Length);
            var vector = new SparseVector(data);

            for (var i = 0; i < data.Length; i++)
            {
                Assert.AreEqual(data[i], vector[i]);
            }
        }

        /// <summary>
        /// Can create a sparse vector from another sparse vector.
        /// </summary>
        [Test]
        public void CanCreateSparseVectorFromAnotherSparseVector()
        {
            var vector = new SparseVector(Data);
            var other = new SparseVector(vector);

            Assert.AreNotSame(vector, other);
            for (var i = 0; i < Data.Length; i++)
            {
                Assert.AreEqual(vector[i], other[i]);
            }
        }

        /// <summary>
        /// Can create a sparse vector from another vector.
        /// </summary>
        [Test]
        public void CanCreateSparseVectorFromAnotherVector()
        {
            var vector = (Vector<Complex32>)new SparseVector(Data);
            var other = new SparseVector(vector);

            Assert.AreNotSame(vector, other);
            for (var i = 0; i < Data.Length; i++)
            {
                Assert.AreEqual(vector[i], other[i]);
            }
        }

        /// <summary>
        /// Can create a sparse vector from user defined vector.
        /// </summary>
        [Test]
        public void CanCreateSparseVectorFromUserDefinedVector()
        {
            var vector = new UserDefinedVector(Data);
            var other = new SparseVector(vector);

            for (var i = 0; i < Data.Length; i++)
            {
                Assert.AreEqual(vector[i], other[i]);
            }
        }

        /// <summary>
        /// Can create a sparse vector with constant values.
        /// </summary>
        [Test]
        public void CanCreateSparseVectorWithConstantValues()
        {
            var vector = new SparseVector(5, new Complex32(5.0f, 1));
            foreach (var t in vector)
            {
                Assert.AreEqual(t, new Complex32(5.0f, 1));
            }
        }

        /// <summary>
        /// Can create a sparse matrix.
        /// </summary>
        [Test]
        public void CanCreateSparseMatrix()
        {
            var vector = new SparseVector(3);
            var matrix = vector.CreateMatrix(2, 3);
            Assert.AreEqual(2, matrix.RowCount);
            Assert.AreEqual(3, matrix.ColumnCount);
        }

        /// <summary>
        /// Can convert a sparse vector to an array.
        /// </summary>
        [Test]
        public void CanConvertSparseVectorToArray()
        {
            var vector = new SparseVector(Data);
            var array = vector.ToArray();
            Assert.IsInstanceOf(typeof(Complex32[]), array);
            CollectionAssert.AreEqual(vector, array);
        }

        /// <summary>
        /// Can convert an array to a sparse vector.
        /// </summary>
        [Test]
        public void CanConvertArrayToSparseVector()
        {
            var array = new[] { new Complex32(1, 1), new Complex32(2, 1), new Complex32(3, 1), new Complex32(4, 1) };
            var vector = new SparseVector(array);
            Assert.IsInstanceOf(typeof(SparseVector), vector);
            CollectionAssert.AreEqual(array, array);
        }

        /// <summary>
        /// Can multiply a sparse vector by a Complex using "*" operator.
        /// </summary>
        [Test]
        public void CanMultiplySparseVectorByComplexUsingOperators()
        {
            var vector = new SparseVector(Data);
            vector = vector * new Complex32(2.0f, 1);

            for (var i = 0; i < Data.Length; i++)
            {
                Assert.AreEqual(Data[i] * new Complex32(2.0f, 1), vector[i]);
            }

            vector = vector * 1.0f;
            for (var i = 0; i < Data.Length; i++)
            {
                Assert.AreEqual(Data[i] * new Complex32(2.0f, 1), vector[i]);
            }

            vector = new SparseVector(Data);
            vector = new Complex32(2.0f, 1) * vector;

            for (var i = 0; i < Data.Length; i++)
            {
                Assert.AreEqual(Data[i] * new Complex32(2.0f, 1), vector[i]);
            }

            vector = 1.0f * vector;
            for (var i = 0; i < Data.Length; i++)
            {
                Assert.AreEqual(Data[i] * new Complex32(2.0f, 1), vector[i]);
            }
        }

        /// <summary>
        /// Can divide a sparse vector by a Complex using "/" operator.
        /// </summary>
        [Test]
        public void CanDivideSparseVectorByComplexUsingOperators()
        {
            var vector = new SparseVector(Data);
            vector = vector / new Complex32(2.0f, 1);

            for (var i = 0; i < Data.Length; i++)
            {
                AssertHelpers.AlmostEqual(Data[i] / new Complex32(2.0f, 1), vector[i], 7);
            }

            vector = vector / 1.0f;
            for (var i = 0; i < Data.Length; i++)
            {
                AssertHelpers.AlmostEqual(Data[i] / new Complex32(2.0f, 1), vector[i], 7);
            }
        }

        /// <summary>
        /// Can calculate an outer product for a sparse vector.
        /// </summary>
        [Test]
        public void CanCalculateOuterProductForSparseVector()
        {
            var vector1 = CreateVector(Data);
            var vector2 = CreateVector(Data);
            var m = Vector<Complex32>.OuterProduct(vector1, vector2);
            for (var i = 0; i < vector1.Count; i++)
            {
                for (var j = 0; j < vector2.Count; j++)
                {
                    Assert.AreEqual(m[i, j], vector1[i] * vector2[j]);
                }
            }
        }

        /// <summary>
        /// Outer product for <c>null</c> sparse vectors throws <c>ArgumentNullException</c>.
        /// </summary>
        [Test]
        public void OuterProductForNullSparseVectorsThrowsArgumentNullException()
        {
            SparseVector vector1 = null;
            var vector2 = CreateVector(Data);
            Assert.Throws<ArgumentNullException>(() => Vector<Complex32>.OuterProduct(vector1, vector2));
            Assert.Throws<ArgumentNullException>(() => Vector<Complex32>.OuterProduct(vector2, vector1));
        }

        /// <summary>
        /// Check sparse mechanism by setting values.
        /// </summary>
        [Test]
        public void CheckSparseMechanismBySettingValues()
        {
            var vector = new SparseVector(10000);

            // Add non-zero elements
            vector[200] = new Complex32(1.5f, 1);
            Assert.AreEqual(new Complex32(1.5f, 1), vector[200]);
            Assert.AreEqual(1, vector.NonZerosCount);

            vector[500] = new Complex32(3.5f, 1);
            Assert.AreEqual(new Complex32(3.5f, 1), vector[500]);
            Assert.AreEqual(2, vector.NonZerosCount);

            vector[800] = new Complex32(5.5f, 1);
            Assert.AreEqual(new Complex32(5.5f, 1), vector[800]);
            Assert.AreEqual(3, vector.NonZerosCount);

            vector[0] = new Complex32(7.5f, 1);
            Assert.AreEqual(new Complex32(7.5f, 1), vector[0]);
            Assert.AreEqual(4, vector.NonZerosCount);

            // Remove non-zero elements
            vector[200] = Complex32.Zero;
            Assert.AreEqual(Complex32.Zero, vector[200]);
            Assert.AreEqual(3, vector.NonZerosCount);

            vector[500] = Complex32.Zero;
            Assert.AreEqual(Complex32.Zero, vector[500]);
            Assert.AreEqual(2, vector.NonZerosCount);

            vector[800] = Complex32.Zero;
            Assert.AreEqual(Complex32.Zero, vector[800]);
            Assert.AreEqual(1, vector.NonZerosCount);

            vector[0] = Complex32.Zero;
            Assert.AreEqual(Complex32.Zero, vector[0]);
            Assert.AreEqual(0, vector.NonZerosCount);
        }

        /// <summary>
        /// Check sparse mechanism by zero multiply.
        /// </summary>
        [Test]
        public void CheckSparseMechanismByZeroMultiply()
        {
            var vector = new SparseVector(10000);

            // Add non-zero elements
            vector[200] = new Complex32(1.5f, 1);
            vector[500] = new Complex32(3.5f, 1);
            vector[800] = new Complex32(5.5f, 1);
            vector[0] = new Complex32(7.5f, 1);

            // Multiply by 0
            vector *= 0;
            Assert.AreEqual(Complex32.Zero, vector[200]);
            Assert.AreEqual(Complex32.Zero, vector[500]);
            Assert.AreEqual(Complex32.Zero, vector[800]);
            Assert.AreEqual(Complex32.Zero, vector[0]);
            Assert.AreEqual(0, vector.NonZerosCount);
        }

        /// <summary>
        /// Can calculate a dot product of two sparse vectors.
        /// </summary>
        [Test]
        public void CanDotProductOfTwoSparseVectors()
        {
            var vectorA = new SparseVector(10000);
            vectorA[200] = 1;
            vectorA[500] = 3;
            vectorA[800] = 5;
            vectorA[100] = 7;
            vectorA[900] = 9;

            var vectorB = new SparseVector(10000);
            vectorB[300] = 3;
            vectorB[500] = 5;
            vectorB[800] = 7;

            Assert.AreEqual(new Complex32(50.0f, 0), vectorA.DotProduct(vectorB));
        }

        /// <summary>
        /// Can pointwise multiple a sparse vector.
        /// </summary>
        [Test]
        public void CanPointwiseMultiplySparseVector()
        {
            var zeroArray = new[] { Complex32.Zero, new Complex32(1.0f, 1), Complex32.Zero, new Complex32(1.0f, 1), Complex32.Zero };
            var vector1 = new SparseVector(Data);
            var vector2 = new SparseVector(zeroArray);
            var result = new SparseVector(vector1.Count);

            vector1.PointwiseMultiply(vector2, result);

            for (var i = 0; i < vector1.Count; i++)
            {
                Assert.AreEqual(Data[i] * zeroArray[i], result[i]);
            }

            Assert.AreEqual(2, result.NonZerosCount);
        }
    }
}