mathnet-numerics/src/UnitTests/LinearAlgebraTests/Single/VectorTests.Norm.cs

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namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Single
{
    using System;
    using NUnit.Framework;

    /// <summary>
    /// Abstract class with the norms set of vector tests.
    /// </summary>
    public abstract partial class VectorTests
    {
        /// <summary>
        /// Can compute 2nd norm.
        /// </summary>
        [Test]
        public void CanComputeNorm()
        {
            var vector = CreateVector(Data);
            AssertHelpers.AlmostEqual(7.416198487095663f, vector.Norm(2), 6);
        }

        /// <summary>
        /// Can compute 1st norm.
        /// </summary>
        [Test]
        public void CanComputeNorm1()
        {
            var vector = CreateVector(Data);
            AssertHelpers.AlmostEqual(15.0f, vector.Norm(1), 7);
        }

        /// <summary>
        /// Can compute square norm.
        /// </summary>
        [Test]
        public void CanComputeSquareNorm()
        {
            var vector = CreateVector(Data);
            AssertHelpers.AlmostEqual(55.0f, vector.Norm(2) * vector.Norm(2), 6);
        }

        /// <summary>
        /// Can compute a norm.
        /// </summary>
        /// <param name="p">The norm index.</param>
        /// <param name="expected">The expected <c>P</c>-norm value.</param>
        [TestCase(1, 15.0f)]
        [TestCase(2, 7.416198487095663f)]
        [TestCase(3, 6.0822019955734001f)]
        [TestCase(10, 5.0540557845353753f)]
        public void CanComputeNormP(int p, float expected)
        {
            var vector = CreateVector(Data);
            AssertHelpers.AlmostEqual(expected, vector.Norm(p), 5);
        }

        /// <summary>
        /// Can compute infinity norm.
        /// </summary>
        [Test]
        public void CanComputeNormInfinity()
        {
            var vector = CreateVector(Data);
            AssertHelpers.AlmostEqual(5.0f, vector.Norm(Single.PositiveInfinity), 7);
        }

        /// <summary>
        /// Can normalize a vector.
        /// </summary>
        [Test]
        public void CanNormalizeVector()
        {
            var vector = CreateVector(Data);
            var result = vector.Normalize(2);
            AssertHelpers.AlmostEqual(0.134839972492648f, result[0], 6);
            AssertHelpers.AlmostEqual(0.269679944985297f, result[1], 6);
            AssertHelpers.AlmostEqual(0.404519917477945f, result[2], 6);
            AssertHelpers.AlmostEqual(0.539359889970594f, result[3], 6);
            AssertHelpers.AlmostEqual(0.674199862463242f, result[4], 6);
        }
    }
}