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Logarithm on Attributes

norita
norita Member Posts: 29 image Learner III
edited June 2021 in Help
Hi!

I wanted to obtain logarithm on my attributes. I used the operator logarithm. I was missing the ability of the operator to handle 0 values within attributes. That's a problem for the logarithm function. I thought it might could handle this but I am not sure if the operator can?
Maybe I have to use than a macro right to type in this formula: log(x + 1) because with this formula it could handle 0.



Best

Nora


Best Answer

  • jwpfau
    jwpfau Employee-RapidMiner, Member Posts: 303 image RM Engineering
    Solution Accepted
    Hi Nora,

    There is probably a better way to do it, but you could wrap the Generate Attributes in a Loop Attributes with reuse results enabled.

    Greetings,
    Jonas

Answers

  • jwpfau
    jwpfau Employee-RapidMiner, Member Posts: 303 image RM Engineering
    edited June 2021
    Hi Nora,

    i know it's not mathematically correct, but i think the operator follows IEEE 754 and does return -Infinity for +/-0.
    But anything below will be converted into a missing value.

    Greetings,
    Jonas
  • norita
    norita Member Posts: 29 image Learner III
    Yes that is true but unfortunate for good predictiors I think.
    Thats why I will do it manually by generating the logarithm by this formula log(x + 1). Do you know how I can perform this for a subset of attributs to generate such logarithmic attributes?

  • norita
    norita Member Posts: 29 image Learner III

    So I am able to do it for one attribute. But how about doing this on a subset of attributes? Is there a quick way to do it?

  • MartinLiebig
    MartinLiebig Administrator, Moderator, Employee-RapidMiner, RapidMiner Certified Analyst, RapidMiner Certified Expert, University Professor Posts: 3,533 image RM Data Scientist
    Hi there,
    you need to combine it with Loop Attributes to get it going.
    Best,
    Martin
    - Sr. Director Data Solutions, Altair RapidMiner -
    Dortmund, Germany

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