CubicInterpolation f = new CubicInterpolation(
x, y,
CubicInterpolation.DerivativeApprox.Spline, false,
CubicInterpolation.BoundaryCondition.NotAKnot, Constants.NULL_REAL,
CubicInterpolation.BoundaryCondition.NotAKnot, Constants.NULL_REAL);
f.update();
checkValues("Not-a-knot spline", f, x, y);
check1stDerivativeValue("Not-a-knot spline", f, x.get(0), 4.0);
check1stDerivativeValue("Not-a-knot spline", f, x.get(n-1), -4.0);
check2ndDerivativeValue("Not-a-knot spline", f, x.get(0), -2.0);
check2ndDerivativeValue("Not-a-knot spline", f, x.get(n-1), -2.0);