Is there support for the Singleton term?

[Unknown]

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.

[Juan Rada-Vilela (admin)]

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?

Cheers.

[Unknown]

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.

[Author]

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