code: public double get(double x, double epsilon)
      {
          Point nearest = getNearest(x, epsilon);
          return nearest.getY();
      }
docs: Returns y for x. This is convenient method. Use getNearest to get exact
  evaluated point.
  @param x
  @param epsilon Evaluated points x cannot differ more
  @return
  @see org.vesalainen.math.CubicSplineCurve#getNearest(double, double)