Logarithm on Attributes

norita

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

jwpfau

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

jwpfau

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

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

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

Hi there,

you need to combine it with Loop Attributes to get it going.

Best,

Martin