Parallel chunk loop


While building a component to apply a parallel loop on a column list, I figured out that the parallel chunk start and end nodes must be at the same level in the workflow. Since I was going to build “Parallel column list loop start” and “Parallel column list loop end” components, I had to put the parallel chunk start and end nodes in two separate components but it doesn’t work that way.
I have the workflow in which I have implemented the idea but unfortunately, I cannot share it as a component.

Is it something that can be fixed?


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Hi @armingrudd , my understanding of Components is that, unlike Metanodes, they are completely independent from the workflow. They’re kind of stand-alone if you will, a bit like a function. So, having loop start in one component and loop end in another is most likely not to work, same as starting a loop in a function and closing the loop (or add loop condition) in another function would not work.

The proper design would be to start the loop, then call the component, and loop end.

Any reason why you are separating the loop start and loop end in 2 separate components?


Hey @bruno29a,

I wish we could pass the required parameters from the start component to the end component and have the loop work fine.
I was working on the idea of having parallel column list loop . I have built the workflow but wanted to share the functionality as two components: “Parallel column list loop start” and “Parallel column list loop end”, so users could use them just like a typical loop construct.

The workflow I’m talking about has a special loop start and loop end construct. The main process goes in the middle. So if I want to share them, I have to split them into two components, so everyone can easily drag and drop them into their workflows. I can argue that starting a loop and ending a loop -just like the nodes- are functions in KNIME. So I should be able to build some special or customized loop and share it as components, right?

I will share the whole workflow with a sample data set for now. Hope we can have loop constructs split into different levels in the future. Why not?


Here is the workflow I promised:
Parallel Column List Loop

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