private void checkOrthogonality(
final PolynomialFunction p1,
final PolynomialFunction p2,
final UnivariateFunction weight,
final double a,
final double b,
final double nonZeroThreshold,
final double zeroThreshold) {
UnivariateFunction f =
new UnivariateFunction() {
public double value(double x) {
return weight.value(x) * p1.value(x) * p2.value(x);
}
};
double dotProduct =
new IterativeLegendreGaussIntegrator(5, 1.0e-9, 1.0e-8, 2, 15).integrate(1000000, f, a, b);
if (p1.degree() == p2.degree()) {
// integral should be non-zero
Assert.assertTrue(
"I(" + p1.degree() + ", " + p2.degree() + ") = " + dotProduct,
FastMath.abs(dotProduct) > nonZeroThreshold);
} else {
// integral should be zero
Assert.assertEquals(
"I(" + p1.degree() + ", " + p2.degree() + ") = " + dotProduct,
0.0,
FastMath.abs(dotProduct),
zeroThreshold);
}
}
