mathnet-numerics/src/UnitTests/LinearAlgebraTests/Single/Solvers/StopCriterium/ResidualStopCriteriumTest.cs

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using System;
using MathNet.Numerics.LinearAlgebra.Single;
using MathNet.Numerics.LinearAlgebra.Single.Solvers.StopCriterium;
using MathNet.Numerics.LinearAlgebra.Solvers;
using NUnit.Framework;

namespace MathNet.Numerics.UnitTests.LinearAlgebraTests.Single.Solvers.StopCriterium
{
    /// <summary>
    /// Residual stop criterium tests.
    /// </summary>
    [TestFixture]
    public sealed class ResidualStopCriteriumTest
    {
        /// <summary>
        /// Create with negative maximum throws <c>ArgumentOutOfRangeException</c>.
        /// </summary>
        [Test]
        public void CreateWithNegativeMaximumThrowsArgumentOutOfRangeException()
        {
            Assert.Throws<ArgumentOutOfRangeException>(() => new ResidualStopCriterium(-0.1f));
        }

        /// <summary>
        /// Create with illegal minimum iterations throws <c>ArgumentOutOfRangeException</c>.
        /// </summary>
        [Test]
        public void CreateWithIllegalMinimumIterationsThrowsArgumentOutOfRangeException()
        {
            Assert.Throws<ArgumentOutOfRangeException>(() => new ResidualStopCriterium(-1));
        }

        /// <summary>
        /// Can create.
        /// </summary>
        [Test]
        public void Create()
        {
            var criterium = new ResidualStopCriterium(1e-6f, 50);
            Assert.IsNotNull(criterium, "There should be a criterium");

            Assert.AreEqual(1e-6f, criterium.Maximum, "Incorrect maximum");
            Assert.AreEqual(50, criterium.MinimumIterationsBelowMaximum, "Incorrect iteration count");
        }

        /// <summary>
        /// Can reset maximum.
        /// </summary>
        [Test]
        public void ResetMaximum()
        {
            var criterium = new ResidualStopCriterium(1e-6f, 50);
            Assert.IsNotNull(criterium, "There should be a criterium");

            criterium.ResetMaximumResidualToDefault();
            Assert.AreEqual(ResidualStopCriterium.DefaultMaximumResidual, criterium.Maximum, "Incorrect maximum");
        }

        /// <summary>
        /// Can reset minimum iterations below maximum.
        /// </summary>
        [Test]
        public void ResetMinimumIterationsBelowMaximum()
        {
            var criterium = new ResidualStopCriterium(1e-6f, 50);
            Assert.IsNotNull(criterium, "There should be a criterium");

            criterium.ResetMinimumIterationsBelowMaximumToDefault();
            Assert.AreEqual(ResidualStopCriterium.DefaultMinimumIterationsBelowMaximum, criterium.MinimumIterationsBelowMaximum, "Incorrect iteration count");
        }

        /// <summary>
        /// Determine status with illegal iteration number throws <c>ArgumentOutOfRangeException</c>.
        /// </summary>
        [Test]
        public void DetermineStatusWithIllegalIterationNumberThrowsArgumentOutOfRangeException()
        {
            var criterium = new ResidualStopCriterium(1e-6f, 50);
            Assert.IsNotNull(criterium, "There should be a criterium");

            Assert.Throws<ArgumentOutOfRangeException>(() => criterium.DetermineStatus(
                -1,
                DenseVector.Create(3, i => 4),
                DenseVector.Create(3, i => 5),
                DenseVector.Create(3, i => 6)));
        }

        /// <summary>
        /// Determine status with non-matching solution vector throws <c>ArgumentException</c>.
        /// </summary>
        [Test]
        public void DetermineStatusWithNonMatchingSolutionVectorThrowsArgumentException()
        {
            var criterium = new ResidualStopCriterium(1e-6f, 50);
            Assert.IsNotNull(criterium, "There should be a criterium");

            Assert.Throws<ArgumentException>(() => criterium.DetermineStatus(
                1,
                DenseVector.Create(4, i => 4),
                DenseVector.Create(3, i => 4),
                DenseVector.Create(3, i => 4)));
        }

        /// <summary>
        /// Determine status with non-matching source vector throws <c>ArgumentException</c>.
        /// </summary>
        [Test]
        public void DetermineStatusWithNonMatchingSourceVectorThrowsArgumentException()
        {
            var criterium = new ResidualStopCriterium(1e-6f, 50);
            Assert.IsNotNull(criterium, "There should be a criterium");

            Assert.Throws<ArgumentException>(() => criterium.DetermineStatus(
                1,
                DenseVector.Create(3, i => 4),
                DenseVector.Create(4, i => 4),
                DenseVector.Create(3, i => 4)));
        }

        /// <summary>
        /// Determine status with non-matching residual vector throws <c>ArgumentException</c>.
        /// </summary>
        [Test]
        public void DetermineStatusWithNonMatchingResidualVectorThrowsArgumentException()
        {
            var criterium = new ResidualStopCriterium(1e-6f, 50);
            Assert.IsNotNull(criterium, "There should be a criterium");

            Assert.Throws<ArgumentException>(() => criterium.DetermineStatus(
                1,
                DenseVector.Create(3, i => 4),
                DenseVector.Create(3, i => 4),
                DenseVector.Create(4, i => 4)));
        }

        /// <summary>
        /// Can determine status with source NaN.
        /// </summary>
        [Test]
        public void DetermineStatusWithSourceNaN()
        {
            var criterium = new ResidualStopCriterium(1e-3f, 10);
            Assert.IsNotNull(criterium, "There should be a criterium");

            var solution = new DenseVector(new[] {1.0f, 1.0f, 2.0f});
            var source = new DenseVector(new[] {1.0f, 1.0f, float.NaN});
            var residual = new DenseVector(new[] {1000.0f, 1000.0f, 2001.0f});

            var status = criterium.DetermineStatus(5, solution, source, residual);
            Assert.AreEqual(IterationStatus.Diverged, status, "Should be diverged");
        }

        /// <summary>
        /// Can determine status with residual NaN.
        /// </summary>
        [Test]
        public void DetermineStatusWithResidualNaN()
        {
            var criterium = new ResidualStopCriterium(1e-3f, 10);
            Assert.IsNotNull(criterium, "There should be a criterium");

            var solution = new DenseVector(new[] {1.0f, 1.0f, 2.0f});
            var source = new DenseVector(new[] {1.0f, 1.0f, 2.0f});
            var residual = new DenseVector(new[] {1000.0f, float.NaN, 2001.0f});

            var status = criterium.DetermineStatus(5, solution, source, residual);
            Assert.AreEqual(IterationStatus.Diverged, status, "Should be diverged");
        }

        /// <summary>
        /// Can determine status with convergence at first iteration.
        /// </summary>
        [Test]
        public void DetermineStatusWithConvergenceAtFirstIteration()
        {
            var criterium = new ResidualStopCriterium();
            Assert.IsNotNull(criterium, "There should be a criterium");

            var solution = new DenseVector(new[] {1.0f, 1.0f, 1.0f});
            var source = new DenseVector(new[] {1.0f, 1.0f, 1.0f});
            var residual = new DenseVector(new[] {0.0f, 0.0f, 0.0f});

            var status = criterium.DetermineStatus(0, solution, source, residual);
            Assert.AreEqual(IterationStatus.Converged, status, "Should be done");
        }

        /// <summary>
        /// Can determine status.
        /// </summary>
        [Test]
        public void DetermineStatus()
        {
            var criterium = new ResidualStopCriterium(1e-3f, 10);
            Assert.IsNotNull(criterium, "There should be a criterium");

            // the solution vector isn't actually being used so ...
            var solution = new DenseVector(new[] {float.NaN, float.NaN, float.NaN});

            // Set the source values
            var source = new DenseVector(new[] {1.000f, 1.000f, 2.001f});

            // Set the residual values
            var residual = new DenseVector(new[] {0.001f, 0.001f, 0.002f});

            var status = criterium.DetermineStatus(5, solution, source, residual);
            Assert.AreEqual(IterationStatus.Continue, status, "Should still be running");

            var status2 = criterium.DetermineStatus(16, solution, source, residual);
            Assert.AreEqual(IterationStatus.Converged, status2, "Should be done");
        }

        /// <summary>
        /// Can reset calculation state.
        /// </summary>
        [Test]
        public void ResetCalculationState()
        {
            var criterium = new ResidualStopCriterium(1e-3f, 10);
            Assert.IsNotNull(criterium, "There should be a criterium");

            var solution = new DenseVector(new[] {0.001f, 0.001f, 0.002f});
            var source = new DenseVector(new[] {0.001f, 0.001f, 0.002f});
            var residual = new DenseVector(new[] {1.000f, 1.000f, 2.001f});

            var status = criterium.DetermineStatus(5, solution, source, residual);
            Assert.AreEqual(IterationStatus.Continue, status, "Should be running");

            criterium.Reset();
            Assert.AreEqual(IterationStatus.Continue, criterium.Status, "Should not have started");
        }

        /// <summary>
        /// Can clone stop criterium.
        /// </summary>
        [Test]
        public void Clone()
        {
            var criterium = new ResidualStopCriterium(1e-3f, 10);
            Assert.IsNotNull(criterium, "There should be a criterium");

            var clone = criterium.Clone();
            Assert.IsInstanceOf(typeof (ResidualStopCriterium), clone, "Wrong criterium type");

            var clonedCriterium = clone as ResidualStopCriterium;
            Assert.IsNotNull(clonedCriterium);

            // ReSharper disable PossibleNullReferenceException
            Assert.AreEqual(criterium.Maximum, clonedCriterium.Maximum, "Clone failed");
            Assert.AreEqual(criterium.MinimumIterationsBelowMaximum, clonedCriterium.MinimumIterationsBelowMaximum, "Clone failed");

            // ReSharper restore PossibleNullReferenceException
        }
    }
}