Workflow loading error (Feature Selection Loop)

Platform: 3.5.3

I have a workflow that has a backwards feature elimination routine which leverages a gradient boosted tree regression model. This feature selection loop is in a metanode and used in a higher level workflow, inside of a loop. The workflow executes as expected, nothing wrong there. However, when I restart KNIME and attempt to load the workflow, I am presented with an error that points to the predictor node of the feature selection loop, stating that the string for key "predictionColumnName" was not found. I am not using any flow variables for the feature selection nodes. This error occurs regardless of whether the prediction column name is set or left alone via the “Change prediction column name” checkbox.

A possible side-effect of this error might be causing KNIME to incorrectly load some parts of the UI, which causes a lot of confusion for me when I try to reconfigure nodes.
For instance:
The feature selection end node is normally set to minimize the selection metric; however - after restarting KNIME, and possibly due to the error in loading the predictor within the feature selection loop - the minimize check box is not checked “on”, as intended and saved in the workflow. The workflow executes as expected. Therefore, the issue is likely the UI not loading the settings properly.

I am only speculating that these two issues might be related. They may be entirely separate issues.


thanks for your report, we’ll have a look at it.


As I experiment further with my workflow, I am no longer receiving the load error. I don’t know what caused the error to subside, but the load error is no longer happening.
However, there remains an issue with proper UI loading. The “Minimize score” checkbox refuses to remain checked after KNIME is restarted. The workflow still executes as intended, with the score being minimized - even though the UI does not indicate it properly.

Hi @davekalpak,

its good to hear when problems solve themselves :wink: Thanks to your detailed description, we were able to reproduce the UI-issue. We are working on a fix there!

Best, Lukas


That’s good to hear!

The least any user of open-source software can do is provide feedback on issues that arise. I appreciate the amount of effort and ingenuity that has gone into the creation of such a powerful tool which is available to the masses. Keep up the great work!

Thank you,