Octopus Multi-Objective Optimization Stops and Doesn’t Continue


I am currently working on multi-objective daylight and thermal optimization on Octopus. The definition is written correctly and simulations perform very well. But the problem is that after approximately 2-3 hours, the optimization stops and does not continiue. Therefore, I get a little amount of results.
Here is the results image:

I tried to run the optimization in several computers, and it performed almost the same. I have a doubt that it may be related to population size and max generations settings, but I am not very sure of it.
By the way I get no errors before or during the optimization.

I would really appreciate it if you suggest any solution or idea regarding that.

Below, I attach the gh file.
28.03.Combined_Optimization_2_Multiple_Results_7.gh (362.5 KB)

Thank you,

I don’t know explicitly about octopus but I’ve never had issues with wallacei MOEO and the LBT/pollination toolkit.

Maybe as a ‘control’ to see if octopus MOO is the issue; re-create the study with Wallacei?
Ive done a pretty egregious number of runs with wallacei, on 48gb RAM with no-issues; as a ‘wallacei should work… theoretically’.

Not sure about octopus but wallacei is NSGA-II

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Is Wallacei a plug-in of GH? I’ve never heard of it but I can surely try.
Octopus can also give non-dominated results as pareto front, but it doesn’t give me enough solutions at the moment.
Thank you for your suggestion. I would surely keep working with Octopus, but I may try Wallacei as well. I hope it works.

yeah Wallacei is a grasshopper plugin, they have a youtube channel that will help get set up, shouldn’t be a hard transition from octopus MOO I’d think!
no problem! I really like this kind of stuff

Yes I enjoy a lot too, until I face a problem:)
Thank you once again, I’ll check their videos.

feel free to message me if you run into any issues with wallacei, I’m pretty free this week and would be happy to share any experience/knowledge on the matter that may aide

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I am very grateful for your help. I will contact if any problem occurs, thank you.

I have used Octopus before, and from your definition nothing seems to be wrong. I think the reason for Octopus to stop (not to crash) is waiting for objective function values, and my guess here is that you should not use the “explode tree” component. I have not run your simulation but I believe the order of the zones’ values might change each run, and when it comes to the point where it retrieves a values from an empty output, it halts. Try replacing the “explode tree” and also remove the other Octopus component.


I understand what you suggest but if I do not use “explode data” and “explode tree” components, I cannot see the numerical value in the RoomEnergyResult component. Therefore, I cannot connect it to the Octopus’ objective function.
Do you have any suggestions for that?

My point is are you sure the 29 outputs will be the same every time it runs? Otherwise there might be some outputs of empty/null where the algorithm will stop. If you’re only retrieving the output of the same room (or some specific index) each time, try using “tree branch” component instead of “explode tree”, and see what happens.


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It took a while, but finally, it worked. I’ve tried many options together with what you have mentioned. I finally got the proper results.

Thank you all for your suggestions.


:metal: :metal: :metal: :metal: :metal: :metal: :metal: :metal:
Looks like a fun study!!

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Thank you!!
It is going to be submitted to a journal very soon. I will provide the link to the article once it is published.
Thank you once again for your support.

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Awesome! please do, I look forward to reading about your work!

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Hey Aybuketaser! :cherry_blossom:

I hope you’re doing well! I wanted to reach out and kindly ask if you could share the link to your amazing paper. I’m really excited to read it and learn from your research. I’m sure it’s going to be an insightful and valuable contribution to the field.

Additionally, if possible, could you please share the .3dm file that’s required to use in the .gh file? It would be incredibly helpful for those of us who are eager to explore and apply your findings practically. Having access to the complete set of resources would allow us to fully understand and implement your work.

Thank you so much in advance for your generosity! I greatly appreciate your willingness to share your expertise and make your work accessible to others. Looking forward to diving into your paper and exploring the accompanying files.

Wishing you continued success and inspiration in all your future endeavors! :star2:

Warm regards,

Could you please send me an e-mail and I can provide the files with you.
Thank you for your interest!