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Maryam H2 avatar image
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Maryam H2 asked Maryam H2 commented

Optimizer Solutions

How we can make the Optimizer test a specific solution? And maybe give the result for all other solutions between optimal/best solutions. For example, if you look at the pic below why optimizer doesn't give any output for "Room_Num" = 9?

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Thanks!


optimizeroptimalsolution
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Jordan Johnson avatar image
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Jordan Johnson answered Maryam H2 commented
You can force the optimizer to run a specific solution by adding it to the list of Scenarios (on the Scenarios tab) and then check the box that says "Use scenarios as possible solutions", on the Optimizer Run tab. It's only visible if you check the "Show advanced options" box.


If the number of possible solutions is less than the number of available CPUs on your machine, OptQuest sometimes gets stuck. To avoid this bug, be sure that the "Max Cores" field on the Advanced tab is set to a non-zero value, such as 4 or 8. A zero indicates that all available cores should be used. If you don't get a message box to appear after either the max iterations or the max wall time has been hit, then OptQuest may be stuck.

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Got it, it worked!


Thanks!
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Ryan Clark avatar image
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Ryan Clark answered Maryam H2 commented

Hello @Maryam H2,

I don't know for sure without looking at your model, but there are a couple options you can modify with the optimizer. First, you can adjust the range of your parameters. If you decrease that range, the solutions will be more densely packed within that range. Secondly, you can change the "Max Solutions" setting, which allows the Optimizer to run more iterations to try to find the optimal solution (see image below): screenshot-2021-09-10-160201.png

Does this help address your problem? Let us know if you need further assistance!


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Thanks! @Ryan Clark

So, the range of the constraints cannot be changed as it will change the way we want it to solve the optimization model. Also, is there any way to define a range for the objective?

I just tried with 100 "Max Solutions" and previously it was 40 and got the same result.

As it's a proprietary model, can you share your email then I can send you the model to take a look at it?





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I have another question about this also:

I see after some point it doesn't consider any new solution, but all of the values of the constraints remain the same. For example, even though the number of rooms has changed from16 to 21, the constraint throughput remains the same as before. Is there any explanation for this?


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Ryan Clark avatar image
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Ryan Clark answered Maryam H2 commented

Hi @Maryam H2,

Another thing you should try is changing the Wall Time to 0 seconds if it isn't already set to that value. That setting only allows the optimizer to run for a certain length of time before stopping, so that might be stopping your model short.

It doesn't appear that you can define a range for the objective, but you can definitely do that for constraints e.g. 10 < x < 20.

I'm not entirely sure about why the throughput doesn't change anymore, even though the number of rooms keeps increasing. It may be because your model has a finite input, so at some point, you reach a maximum in your throughput.

I hope this helps!

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Thanks for the answer!


So, what about if the Wall time is already set to 0?

I still don't understand why Optimizer doesn't test some of the solutions? why there is a gap between solutions?

And for my last question did you mean that I should add the objects to the model as many as I want the Optimizer to test?


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Hi @Maryam H2,

I'm not sure about the Wall Time then... And I'm not sure about your other questions about the solutions from the optimizer, either.

As for your last question, you should have the parameter linked to the number of members in the object group, so it changes the number of objects whenever the parameter changes.

To help you more, I would need to look at your model, so please send me an email with your model attached at [email protected].. Thanks!

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Maryam H2 avatar image Maryam H2 Ryan Clark ♦ ·
Great, I'll do. Thanks!
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