private double exactIntegration(PolynomialFunction p, double a, double b) {
final double[] coeffs = p.getCoefficients();
double yb = coeffs[coeffs.length - 1] / coeffs.length;
double ya = yb;
for (int i = coeffs.length - 2; i >= 0; --i) {
yb = yb * b + coeffs[i] / (i + 1);
ya = ya * a + coeffs[i] / (i + 1);
}
return yb * b - ya * a;
}
/** {@inheritDoc} */
@Override
public double value(final double x, final double... parameters) throws NoDataException {
return PolynomialFunction.evaluate(parameters, x);
}