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Unit Tests: Interpolation I

la-knuth
Christoph Ruegg 16 years ago
parent
commit
2529512a85
  1. 75
      src/UnitTests/InterpolationTests/LinearInterpolationCase.cs
  2. 102
      src/UnitTests/InterpolationTests/NevillePolynomialTest.cs
  3. 2
      src/UnitTests/UnitTests.csproj

75
src/UnitTests/InterpolationTests/LinearInterpolationCase.cs

@ -0,0 +1,75 @@
// <copyright file="LinearInterpolationCase.cs" company="Math.NET">
// Math.NET Numerics, part of the Math.NET Project
// http://numerics.mathdotnet.com
// http://github.com/mathnet/mathnet-numerics
// http://mathnetnumerics.codeplex.com
//
// Copyright (c) 2002-2011 Math.NET
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
// </copyright>
namespace MathNet.Numerics.UnitTests.InterpolationTests
{
using Distributions;
using Numerics.Random;
internal static class LinearInterpolationCase
{
public static void Build(out double[] x, out double[] y, out double[] xtest, out double[] ytest, int samples = 3, double sampleOffset = -0.5, double slope = 2.0, double intercept = -1.0)
{
// Fixed-seed "random" distribution to ensure we always test with the same data
var uniform = new ContinuousUniform
{
RandomSource = new MersenneTwister(42)
};
// build linear samples
x = new double[samples];
y = new double[samples];
for (int i = 0; i < x.Length; i++)
{
x[i] = i + sampleOffset;
y[i] = x[i] * slope + intercept;
}
// build linear test vectors randomly between the sample points
xtest = new double[samples + 1];
ytest = new double[samples + 1];
if (samples == 1)
{
// y = const
xtest[0] = sampleOffset - uniform.Sample();
xtest[1] = sampleOffset + uniform.Sample();
ytest[0] = ytest[1] = sampleOffset * slope + intercept;
}
else
{
for (int i = 0; i < xtest.Length; i++)
{
xtest[i] = (i - 1) + sampleOffset + uniform.Sample();
ytest[i] = xtest[i] * slope + intercept;
}
}
}
}
}

102
src/UnitTests/InterpolationTests/NevillePolynomialTest.cs

@ -0,0 +1,102 @@
// <copyright file="InterpolationTest.cs" company="Math.NET">
// Math.NET Numerics, part of the Math.NET Project
// http://numerics.mathdotnet.com
// http://github.com/mathnet/mathnet-numerics
// http://mathnetnumerics.codeplex.com
//
// Copyright (c) 2002-2011 Math.NET
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
// </copyright>
namespace MathNet.Numerics.UnitTests.InterpolationTests
{
using Interpolation;
using Interpolation.Algorithms;
using NUnit.Framework;
[TestFixture]
public class NevillePolynomialTest
{
readonly double[] _t = new[] { 0.0, 1.0, 3.0, 4.0 };
readonly double[] _x = new[] { 0.0, 3.0, 1.0, 3.0 };
/// <summary>
/// Verifies that the interpolation matches the given value at all the provided sample points.
/// </summary>
[Test]
public void FitsAtSamplePoints()
{
IInterpolation interpolation = new NevillePolynomialInterpolation(_t, _x);
for (int i = 0; i < _t.Length; i++)
{
// verify the interpolated values exactly at the sample points.
Assert.AreEqual(_x[i], interpolation.Interpolate(_t[i]), "A Exact Point " + i);
double interpolatedValue;
double secondDerivative;
interpolation.Differentiate(_t[i], out interpolatedValue, out secondDerivative);
Assert.AreEqual(_x[i], interpolatedValue, "B Exact Point " + i);
}
}
/// <summary>
/// Verifies that at points other than the provided sample points, the interpolation matches the one computed by Maple as a reference.
/// </summary>
/// <remarks>
/// Maple:
/// with(CurveFitting);
/// evalf(subs({x=0.1},PolynomialInterpolation([[0,0],[1,3],[3,1],[4,3]], x)),20);
/// </remarks>
[Test, Sequential]
public void FitsAtArbitraryPointsWithMaple(
[Values(0.1, 0.4, 1.1, 3.2, 4.5, 10.0, -10.0)] double t,
[Values(.57225, 1.884, 3.0314166666666666667, 1.034666666666666667, 6.28125, 277.5, -1010.8333333333333333)] double x,
[Values(1e-15, 1e-15, 1e-15, 1e-15, 1e-15, 1e-15, 1e-12)] double maxAbsoluteError)
{
IInterpolation interpolation = new NevillePolynomialInterpolation(_t, _x);
Assert.AreEqual(x, interpolation.Interpolate(t), maxAbsoluteError, "Interpolation at {0}", t);
double interpolatedValue;
double secondDerivative;
interpolation.Differentiate(t, out interpolatedValue, out secondDerivative);
Assert.AreEqual(x, interpolatedValue, maxAbsoluteError, "Interpolation as by-product of differentiation at {0}", t);
}
/// <summary>
/// Verifies that the interpolation supports the linear case appropriately
/// </summary>
[Test]
public void SupportsLinearCase([Values(2, 4, 12)] int samples)
{
double[] x, y, xtest, ytest;
LinearInterpolationCase.Build(out x, out y, out xtest, out ytest, samples);
IInterpolation interpolation = new NevillePolynomialInterpolation(x, y);
for (int i = 0; i < xtest.Length; i++)
{
Assert.AreEqual(ytest[i], interpolation.Interpolate(xtest[i]), 1e-13, "Linear with {0} samples, sample {1}", samples, i);
}
}
}
}

2
src/UnitTests/UnitTests.csproj

@ -113,6 +113,8 @@
<Compile Include="IntegralTransformsTests\MatchingNaiveTransformTest.cs" />
<Compile Include="IntegralTransformsTests\ParsevalTheoremTest.cs" />
<Compile Include="IntegrationTests\IntegrationTest.cs" />
<Compile Include="InterpolationTests\InterpolationTest.cs" />
<Compile Include="InterpolationTests\LinearInterpolationCase.cs" />
<Compile Include="LinearAlgebraProviderTests\Double\LinearAlgebraProviderTests.cs">
<SubType>Code</SubType>
</Compile>

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