Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

- JMP User Community
- :
- Discussions
- :
- How to limit the number of ingredients in a DOE

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

How to limit the number of ingredients in a DOE

May 29, 2020 3:01 AM
(863 views)

I have a large number of ingredients, and want to constrain the number that feature in any one formulation.

So I have a Custom Design constraint ("Disallowed Combinations Script") of the form…

`((Ing1>0) + (Ing2>0) + (Ing3>0) +……+ (IngX>0)) > N`

Where IngX is the level Ingredient X. Not treating this as a Mixture.

I’m getting the attached error.

Interestingly reversing the sign, i.e. MINIMISING the number of ingredients to N doesn't appear to be a problem.

Any help welcome...

- Tags:
- constraints
- doe

3 REPLIES 3

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: How to limit the number of ingredients in a DOE

Created:
May 29, 2020 5:16 AM
| Last Modified: May 29, 2020 5:27 AM
(846 views)
| Posted in reply to message from MattRowson 05-29-2020

The expression that you are using appears to be the correct form assuming that all the factor ranges are 0 to 1. You might not be adding mixture factors (ingredients) to the design but the disallowed combination that you defined is forcing linear dependencies on the factors that produce a singularity in the model matrix that JMP uses to optimize the design.

Do you really want less than N ingredients in each mixture or you want to be sure to have exactly N ingredients in each mixture?

Learn it once, use it forever!

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: How to limit the number of ingredients in a DOE

Many thanks for this Mark.

You specify..."assuming all ranges 0 to 1". Does this matter? I had expected my constraint to limit the number of nonzero formulations to N (or fewer)

N or fewer is the objective, and I also want to vary the concentration (not just inclusion), but I can build on the suggestion in your second mail I think. Many thanks.

Highlighted
##

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Re: How to limit the number of ingredients in a DOE

Created:
May 29, 2020 6:06 AM
| Last Modified: May 29, 2020 6:50 AM
(837 views)
| Posted in reply to message from MattRowson 05-29-2020

I made some assumptions about your situation and came up with a way to accomplish this design.

Say that I have 5 candidate ingredients but I only want to include 3 of them at a time. I added 3 categorical factors with 5 levels.

Then I created the following expression for disallowed combinations.

`Ingredient 1 == Ingredient 2 | Ingredient 1 == Ingredient 3 | Ingredient 2 == Ingredient 3`

Then I assumed a main effects model and 20 runs.

Here is the complete script for this example for you to play with.

```
DOE(
Custom Design,
{Add Response( Maximize, "Y", ., ., . ),
Add Factor( Categorical, {"L1", "L2", "L3", "L4", "L5"}, "Ingredient 1", 0 ),
Add Factor( Categorical, {"L1", "L2", "L3", "L4", "L5"}, "Ingredient 2", 0 ),
Add Factor( Categorical, {"L1", "L2", "L3", "L4", "L5"}, "Ingredient 3", 0 ),
Set Random Seed( 102498840 ), Number of Starts( 10 ), Add Term( {1, 0} ),
Add Term( {1, 1} ), Add Term( {2, 1} ), Add Term( {3, 1} ),
Add Alias Term( {1, 1}, {2, 1} ), Add Alias Term( {1, 1}, {3, 1} ),
Add Alias Term( {2, 1}, {3, 1} ), Set Sample Size( 20 ),
Disallowed Combinations(
Ingredient 1 == Ingredient 2 | Ingredient 1 == Ingredient 3 | Ingredient 2
== Ingredient 3
), Simulate Responses( 0 ), Save X Matrix( 0 )}
);
```

Learn it once, use it forever!

Article Labels

There are no labels assigned to this post.