How to make sure that sequences created by optquest are not repetitive in my sequence optimization sample model?

Question

question

asb.p asked Jul 07 2016 at 3:22 PM Jordan Johnson commented Jul 28 2016 at 6:59 PM

How to make sure that sequences created by optquest are not repetitive in my sequence optimization sample model?

Hello All,

I want to customize optQuest in flexsim to give me best sequence of parts I need to load on to the main line. I have used cells in the "Seq" column of global table "LineUp" as variables in optquest. This is made automated by using on model start trigger and on model trigger.

Optimizer is working fine giving results to my performance measure "SimulationEndTime".

How to modify this / how to make sure that optimizer will not create repeatitive sequences.

Example:

Case 1: Seq no Part

1 A

2 B

3 B

Case 2: Seq no Part

1 A

3 B

2 B

In actual Case1 & Case2 are same. Sequence created by optquest in the model i have attached will some iterations repeated how to eliminate them?

Thanks & Regards,

Praneeth Akondi

1157-seqopt-final1.fsm

Software Version:

FlexSim 16.1.0

optquest sequence optimization

1157-seqopt-final1.fsm (24.3 KiB)

______

Cookie preferences

Your privacy is important to us and so is an optimal experience. To help us customize information and build applications, we collect data about your use of this site.

May we collect and use your data?

Learn more about the Third Party Services we use and our Privacy Statement.

Strictly necessary – required for our site to work and to provide services to you

These cookies allow us to record your preferences or login information, respond to your requests or fulfill items in your shopping cart.

YES

Improve your experience – allows us to show you what is relevant to you

These cookies enable us to provide enhanced functionality and personalization. They may be set by us or by third party providers whose services we use to deliver information and experiences tailored to you. If you do not allow these cookies, some or all of these services may not be available for you.

YES

NO

Customize your advertising – permits us to offer targeted advertising to you

These cookies collect data about you based on your activities and interests in order to show you relevant ads and to track effectiveness. By collecting this data, the ads you see will be more tailored to your interests. If you do not allow these cookies, you will experience less targeted advertising.

YES

NO

Are you sure you want a less customized experience?

We can access your data only if you select "yes" for the categories on the previous screen. This lets us tailor our marketing so that it's more relevant for you. You can change your settings at any time by visiting our privacy statement

Your experience. Your choice.

We care about your privacy. The data we collect helps us understand how you use our products, what information you might be interested in, and what we can improve to make your engagement with Autodesk more rewarding.

May we collect and use your data to tailor your experience?

Explore the benefits of a customized experience by managing your privacy settings for this site or visit our Privacy Statement to learn more about your options.

Answer 1 · 2016-07-07T18:02:11Z

Jordan Johnson answered Jul 07 2016 at 6:02 PM Jordan Johnson commented Jul 28 2016 at 6:59 PM

In this situation, you can't use permutation variables. As you have correctly noticed, the Optimizer considers "1-2-3" to be different from "1-3-2". You will probably need to define all the unique sequences in a table in the model, like this:

	Step 1	Step 2	Step 3
Sequence 1	A	B	B
Sequence 2	B	B	A
Sequence 3	B	A	B

Then, change your model to use a sequence based on the row number. Replace the permutation variables in your optimization with a single Design variable. Design variables are just like Integer variables, except that they represent options, rather than values. The Design variable should control which row number your model uses for a particular run.

· 3

asb.p commented · Jul 08 2016 at 2:02 AM

Hello Jordan,

Thanks for the reply,

But creating unique sequences for list of lets say 100 part types in a 1000 sequences demand is almost impossible. so is there any way in optquest to consider part types also while creating sequences? So that there is no need to create unique sequences. @jordan.johnson

0 ·

asb.p commented · Jul 26 2016 at 4:54 AM

@jordan.johnson

Latest model with simplified On model reset & On model open codes.seqopt-final1.fsm

But at the end of the optimizer run I can see optimizer evaluating same scequences multiple times.

Please let me know if there is a way to include Part types also in optimization.

0 ·

seqopt-final1.fsm (25.3 KiB)

Jordan Johnson ♦♦ asb.p commented · Jul 28 2016 at 6:59 PM

OptQuest assumes that every permutation of a sequence is possible and unique. If that is not true, you have a few options.

Reduce the number of permutation variables, until each possible permutation represents a unique sequence. You might have to ignore some sequences, but you won't have duplicates, either.
You can let OptQuest simulate duplicate sequences. With that many permutations, OptQuest is unlikely to do an exhaustive search of the design space, and even more unlikely to run duplicate sequences. Depending on which permutations it chooses to try, it may run many duplicates, or it may run very few. The time wasted will depend on how many permutations result in a duplicate sequence.
You can enumerate all possible unique sequences. This will be tedious, and may take significant time for the user.

Each of these three options represents a trade off between user time and computation time. You should analyze your situation and determine which method will get you the best results the fastest. Remember that the optimizer, unless it searches all possible solutions (impossible with 100 permutation variables), will give you the best answer it finds before you stop it.

0 ·

question