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Default value of nominal attributes
Schalkekid
Member Posts: 17 
Maven
Hi there,
as I am working with nominal attributes very often, I found out that the default value of nominal attributes (also polynominal and binominal ones) is set to 0.0d in the AbstractAttribute-class.
If you are using the default-value-check in the Tools-class a nominal attribute containing the value mapped on first position in the nominal mapping will be marked as containing a default value. This might lead to the ban of the attribute in special cases (for instance in the creation of SVMExamples).
I don't think that this is a problem in everyday work but perhaps it's remarkable for some users.
Unfortunately, I don't have a really good idea how to overcome that problem!
I wrote an SVM-kernel for processing nominal values, and I had to manually check for nominal attributes to be put into the attribute map in any case, also if they are containing "default values".
Best,
Felix
as I am working with nominal attributes very often, I found out that the default value of nominal attributes (also polynominal and binominal ones) is set to 0.0d in the AbstractAttribute-class.
If you are using the default-value-check in the Tools-class a nominal attribute containing the value mapped on first position in the nominal mapping will be marked as containing a default value. This might lead to the ban of the attribute in special cases (for instance in the creation of SVMExamples).
I don't think that this is a problem in everyday work but perhaps it's remarkable for some users.
Unfortunately, I don't have a really good idea how to overcome that problem!
I wrote an SVM-kernel for processing nominal values, and I had to manually check for nominal attributes to be put into the attribute map in any case, also if they are containing "default values".
Best,
Felix
0
Answers
actually this default value is needed for sparse attributes. Otherwise they won't work. I don't think we can change that anyway in the current data core. But you might add a feature request for that. We then can take this into account when designing the new column based core.
Greetings,
Sebastian
thank you!
Best,
Felix