private static ISpectralOdeOperator <double[][]> CreateOperator(int quadratureNodesCount)
{
// Used to calculate coeffs that are represented as integrals
var quadratureNodes = new Segment(0, 1).GetUniformPartition(quadratureNodesCount);
var cosSystem = new CosSystem();
var sobCosSystem = new SobolevCosSystem();
var op = new CosSpectralOdeOperator(Natural.NumbersWithZero.Select(k => cosSystem.Get(k)),
Natural.NumbersWithZero.Select(k => sobCosSystem.Get(k)), quadratureNodes);
return(op);
}
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);
}