Hello everyone!
I consider myself as a beginner KNIME user, my question might be a bit trivial.
I have a workflow (image attached) that seems to be working fine. However, instead of the first Column Filter node, which selects a specific column containing an element of interest for my model, I believe I need to perform the Parameter Optimization Loop for all other available columns/elements. These elements would be assigned as Target Columns.
My initial idea was to replace the Column Filter node with a Column List Loop Start node, thus creating another loop. Unfortunately, this approach isn’t working: the H2O Cross Validation Loop Start shows the error “Can’t merge FlowVariable Stacks! (likely a loop problem.)”. Even when I add a Loop End (Column Append) node at the end of the workflow, the problem persists.
I suspect the error occurs because both the Column List Loop Start and the H2O Cross Validation Loop Start nodes automatically create a “currentIteration” Flow Variable upon execution, but I’m not certain.
I would really appreciate any guidance on how to resolve this issue.
Thanks in advance!
