public void TestInterpolationMethod_CubicSpline_BoundaryNatural()
{
double[] t = new double[] { -2.0, -1.0, 0.0, 1.0, 2.0 };
double[] x = new double[] { 1.0, 2.0, -1.0, 0.0, 1.0 };
IInterpolationMethod method = Interpolation.CreateNaturalCubicSpline(t, x);
Assert.IsInstanceOfType(typeof(CubicSplineInterpolation), method, "Type");
for (int i = 0; i < t.Length; i++)
{
// verify the interpolated values exactly at the sample points.
Assert.AreEqual(x[i], method.Interpolate(t[i]), "A Exact Point " + i.ToString());
}
// Maple: "with(CurveFitting);"
// Maple: "evalf(subs({x=-2.4},Spline([[-2,1],[-1,2],[0,-1],[1,0],[2,1]], x, degree=3, endpoints='natural')),20);"
NumericAssert.AreAlmostEqual(.144000000000000000, method.Interpolate(-2.4), 1e-15, "A -2.4");
NumericAssert.AreAlmostEqual(1.7906428571428571429, method.Interpolate(-0.9), 1e-15, "A -0.9");
NumericAssert.AreAlmostEqual(.47321428571428571431, method.Interpolate(-0.5), 1e-15, "A -0.5");
NumericAssert.AreAlmostEqual(-.80992857142857142857, method.Interpolate(-0.1), 1e-15, "A -0.1");
NumericAssert.AreAlmostEqual(-1.1089285714285714286, method.Interpolate(0.1), 1e-15, "A 0.1");
NumericAssert.AreAlmostEqual(-1.0285714285714285714, method.Interpolate(0.4), 1e-15, "A 0.4");
NumericAssert.AreAlmostEqual(.30285714285714285716, method.Interpolate(1.2), 1e-15, "A 1.2");
NumericAssert.AreAlmostEqual(189, method.Interpolate(10.0), 1e-15, "A 10.0");
NumericAssert.AreAlmostEqual(677, method.Interpolate(-10.0), 1e-15, "A -10.0");
}
private List <Position> GetPoints(List <Position> points, int type)
{
try
{
List <Position> result = new List <Position>();
IInterpolationMethod method = null;
List <double> xs = new List <double>();
List <double> ys = new List <double>();
if (type > 0)
{
for (int i = 0; i < points.Count; i++)
{
xs.Add(points[i].X);
ys.Add(points[i].Z);
}
}
if (type == 0)
{
result.AddRange(points);
}
else if (type == 1)
{
method = Interpolation.CreateNaturalCubicSpline(xs, ys);
}
else if (type == 2)
{
method = Interpolation.CreateAkimaCubicSpline(xs, ys);
}
if (method != null)
{
for (int i = 0; i < points.Count; i++)
{
Position p1 = points[i];
Position p2 = points[i + 1];
double x = (p1.X + p2.X) / 2;
}
}
return(result);
}
catch (System.Exception ex)
{
Log.Error(hisTag, "GetPoints", "Exception:" + ex);
return(null);
}
}
public void TestInterpolationMethod_CubicSpline_BoundaryNatural()
{
double[] t = new double[] { -2.0, -1.0, 0.0, 1.0, 2.0 };
double[] x = new double[] { 1.0, 2.0, -1.0, 0.0, 1.0 };
IInterpolationMethod method = Interpolation.CreateNaturalCubicSpline(t, x);
Assert.That(method, Is.TypeOf(typeof(CubicSplineInterpolation)), "Type");
for (int i = 0; i < t.Length; i++)
{
// verify the interpolated values exactly at the sample points.
Assert.That(method.Interpolate(t[i]), Is.EqualTo(x[i]), "A Exact Point " + i.ToString());
}
// Maple: "with(CurveFitting);"
// Maple: "evalf(subs({x=-2.4},Spline([[-2,1],[-1,2],[0,-1],[1,0],[2,1]], x, degree=3, endpoints='natural')),20);"
Assert.That(method.Interpolate(-2.4), NumericIs.AlmostEqualTo(.144000000000000000, 1e-15), "A -2.4");
Assert.That(method.Interpolate(-0.9), NumericIs.AlmostEqualTo(1.7906428571428571429, 1e-15), "A -0.9");
Assert.That(method.Interpolate(-0.5), NumericIs.AlmostEqualTo(.47321428571428571431, 1e-15), "A -0.5");
Assert.That(method.Interpolate(-0.1), NumericIs.AlmostEqualTo(-.80992857142857142857, 1e-15), "A -0.1");
Assert.That(method.Interpolate(0.1), NumericIs.AlmostEqualTo(-1.1089285714285714286, 1e-15), "A 0.1");
Assert.That(method.Interpolate(0.4), NumericIs.AlmostEqualTo(-1.0285714285714285714, 1e-15), "A 0.4");
Assert.That(method.Interpolate(1.2), NumericIs.AlmostEqualTo(.30285714285714285716, 1e-15), "A 1.2");
Assert.That(method.Interpolate(10.0), NumericIs.AlmostEqualTo((double)189, 1e-15), "A 10.0");
Assert.That(method.Interpolate(-10.0), NumericIs.AlmostEqualTo((double)677, 1e-15), "A -10.0");
// Test Linear Case
for (int k = 2; k < 6; k++)
{
double[] linx, liny, linxtest, linytest;
BuildLinearCase(2, k + 1, out linx, out liny, out linxtest, out linytest);
IInterpolationMethod linearMethod = Interpolation.CreateNaturalCubicSpline(linx, liny);
for (int i = 0; i < linxtest.Length; i++)
{
Assert.That(linearMethod.Interpolate(linxtest[i]), NumericIs.AlmostEqualTo(linytest[i], 1e-12), String.Format("Linear k={0} i={1}", k, i));
}
}
}
