/// <summary>Initializes a new instance of the <see cref="Algorithm"/> class.
/// </summary>
/// <param name="gaussLaguerreConstantAbscissasIntegrator">The <see cref="GaussLaguerreConstAbscissaIntegrator"/> object which serves as factory for the current object.</param>
internal Algorithm(GaussLaguerreConstAbscissaIntegrator gaussLaguerreConstantAbscissasIntegrator)
{
m_IntegratorFactory = gaussLaguerreConstantAbscissasIntegrator;
if (m_IntegratorFactory.m_AlphaIsZero == true)
{
WeightFunction = OneDimNumericalIntegrator.WeightFunction.Create(x => Math.Exp(-x));
}
else
{
WeightFunction = OneDimNumericalIntegrator.WeightFunction.Create(x => Math.Exp(-x) * Math.Pow(x, m_IntegratorFactory.Alpha));
}
}
public void GetValue_ZeroAlphaExpOfMinusX_BenchmarkResult(
[Values(100, 125)]
int order)
{
var gaussLaguerreConstantAbscissasIntegrator = new GaussLaguerreConstAbscissaIntegrator(order);
var numericalIntegrator = gaussLaguerreConstantAbscissasIntegrator.Create();
numericalIntegrator.FunctionToIntegrate = (x, k) => Math.Exp(-x); // i.e. \int_0^\infty e^{-2*x} = 1/2
double expected = 0.5;
double actual = numericalIntegrator.GetValue();
Assert.That(actual, Is.EqualTo(expected).Within(1E-6), String.Format("1-dimensional integrator {0}.", numericalIntegrator.Factory.Name));
}
public void GetValue_One_BenchmarkResult(
[Values(5, 10, 22)]
int alpha,
[Values(100, 125)]
int order)
{
var gaussLaguerreConstantAbscissasIntegrator = new GaussLaguerreConstAbscissaIntegrator(alpha, order);
var numericalIntegrator = gaussLaguerreConstantAbscissasIntegrator.Create();
numericalIntegrator.FunctionToIntegrate = (x, k) => 1.0;
double expected = GetFaculty(alpha); // see for example § 21.6.2 "Taschenbuch der Mathematik", Bronstein, Semendjajew, Musiol, Mühlig, 1995
double actual = numericalIntegrator.GetValue();
Assert.That(actual, Is.EqualTo(expected).Within(1E-7).Percent, String.Format("1-dimensional integrator {0}.", numericalIntegrator.Factory.Name));
}