/// <summary>
/// Calculates $c_k(f_j)$
/// </summary>
/// <param name="i"></param>
/// <param name="k"></param>
/// <param name="fArgs"></param>
/// <returns></returns>
private double CalcCoeff(int i, int k, double[][] fArgs)
{
// qk[j] = $f_k(h t_j, \eta_0(t_j), ..., \eta_{m-1}(t_j)) * phi_k(t_j)$,
// so qk is a vector of values of function $q_k(t)=f_k(ht,\eta_0(t),...) phi(t)$ in _nodes
var qk = _nodes.Select((t, j) => _f[i].Invoke(fArgs[j]) * _phiCached[k](t));
return(Integrals.Trapezoid(qk.ToArray(), _nodes));
}
public void TrapezoidDiscreteTest()
{
RunTestCases(
testCase =>
{
var nodes = GenerateNodes(testCase.A, testCase.B, testCase.NodesCount);
var fD = nodes.Select(t => testCase.Func(t)).ToArray();
return(Integrals.Trapezoid(fD, nodes));
});
}
public void CosSytemOrthonormality()
{
var cosSystem = new CosSystem();
for (int i = 0; i < 100; i++)
{
var i1 = i;
var v = Integrals.Trapezoid(x => cosSystem.Get(i1)(x) * cosSystem.Get(i1)(x), 0, 1, 10000);
Assert.AreEqual(1, v, 0.0000001);
}
var val = Integrals.Trapezoid(x => cosSystem.Get(0)(x) * cosSystem.Get(5)(x), 0, 1, 10000);
Assert.AreEqual(0, val, 0.0000001);
val = Integrals.Trapezoid(x => cosSystem.Get(4)(x) * cosSystem.Get(5)(x), 0, 1, 10000);
Assert.AreEqual(0, val, 0.0000001);
}
public void TrapezoidTest()
{
RunTestCases(
testCase => Integrals.Trapezoid(testCase.Func, GenerateNodes(testCase.A, testCase.B, testCase.NodesCount))
);
}
public void TrapezoidEquiDistantNetTest()
{
RunTestCases(
testCase => Integrals.Trapezoid(testCase.Func, testCase.A, testCase.B, testCase.NodesCount)
);
}
private double coeffByDef(int n)
{
var w = Walsh.Get(n - 1);
return(Integrals.Trapezoid(x => df(x) * w(x), 0, 1, 10000));
}
