home Forums # Technical Support Is there support for the Singleton term?

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    Hi, I’ve just acquired a Student License for QtFuzzylite and so far I’m liking it. However, I have not found a simple way to define a Singleton term (a fuzzy set whose support is a single point in U with a membership function of ‘height’). Maybe in FuzzyLite is called differently. So far I have achieved similar results by setting a Rectangle term with the same value for ‘end’ and ‘start’. The problem is that in QtFuzzyLite the resulting graphic representation is invisible, although it works well during rule evaluation. I imagine that with a Discrete term it could also be possible. Nonetheless, I would like to know if there is a simpler way to do it.

    Thank you in advance.


    Hi Amauri,

    Thank you very much for your support purchasing a license.

    I think you are looking for the Constant term. Please check it out. Otherwise, could you please export your controller to FLL to see your configuration?



    Hi Juan,

    Thank you for the quick response. I’m sorry I didn’t respond before, I got caught up in work and school.

    I don’t think that the Constant term is what I’m looking for, as the membership value is always a constant value irrespective of the value of x, i.e., μ(x)=c.

    What I meant was a term that has a single value with membership value of 1.0, which is useful to deal with crisp values, such as mapping categorical values to numerical values that can be used in a fuzzy inference engine.

    For instance, for a hypothetical SingletonTerm Java class with the constructor

    public SingletonTerm(String name, double value)

    and the method

    public double membership(double x) { return x == this.value ? 1.0 : 0.0; }

    we could represent categorical data like this:

    SingletonTerm no = new SingletonTerm("No", 0.0)
    SingletonTerm yes = new SingletonTerm("Yes", 1.0)
    SingletonTerm unknown = new SingletonTerm("Unknown", 2.0)

    For reference, this kind of term is called singletonShape in the Fuzzy Markup Language, and SingletonFuzzySet in FuzzyJ.

    Thank you in advance.

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