Calculate A Derivation

[oso91]

Dear KNIME Forum,

I´m currently working with Timeseries and I´m trying to find a comfortable Way to Calculate the derivation of my timeseries.(Means I only want to know the difference from row to row)

I Created the following workflow(see picture). My Idea was to create a LagColumn and substract it from my actual column and it works. The only problem I have is that I have to change it quite frequently and there are a lot of Math Nodes to configure this way.
The Lag Column Part is nicely looped but I have to manually configure each Math node, which is uncomfortable.

If anyone can think of a good way to further automate it or maybe there is a Node I havent found yet, I would be really thankful. I already tried using flow-variables on the math nodes with little success.

Thank you a lot for your help.

Oso

Knime_Forum_Question.knwf (25.8 KB)

[ScottF]

Hi @oso91 -

Have you tried out the Math Formula (Multi Column) node? Sometimes you can use it to replace a whole series of Math Formula nodes. I don’t know if this would work for your use case or not but it might be worth a try.

For example, here’s a configuration screenshot of performing the same operation on a number of columns, which are explicitly defined in the Exclude/Include dialog.

[oso91]

I don´t have it. Is it part of a new Update?

[ScottF]

UPDATE: The Math Formula (Multi Column) node is newly available to version 3.5. So you’ll need to update your version of KNIME Analytics Platform to use it. Sorry for the confusion!

[oso91]

Ah ok, thanks for the info Scott!

[oso91]

Solution found without updates/new nodes:

R-Snippet Code:

input <- knime.in
knime.out <- data.frame(c(0,diff(input[,1])))

-> the Column Rename Node gets the column name as a flow variable. If you don´t do this, every column will be named “output”