class FuAlgo {

    double getTristimulusValue(double[] spectrum, double[] factors) {
        if (spectrum.length != factors.length) {
            throw new IllegalArgumentException("The spectrum must have equal length as factors.");
        }
        double summation = 0;
        for (int i = 0; i < spectrum.length; i++) {
            summation = (spectrum[i] * factors[i]) + summation;
        }
        return summation;
    }

    public  FuAlgo(Instrument instrument);
      FuAlgo();

}