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Stop condition expression

How do I set up the stop condition if I want the solver to stop when the point probe expression ppb1 is less than a value?

4 Replies Last Post Nov 2, 2012, 4:27 PM EDT
COMSOL Moderator

Hello Collin Mui

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Posted: 5 years ago Nov 2, 2012, 5:58 AM EDT
I have the same problem.

The stop condition expression that I use is

mod1.ppb1<0.1

where mod1 is the index from the model and ppb1 is the point probe.

The expression is well evaluated and the model works but the stop condition isn't.

Does anybody know why?

Paul
I have the same problem. The stop condition expression that I use is mod1.ppb1

Posted: 5 years ago Nov 2, 2012, 5:59 AM EDT
If I use

mod1.ppb1-0.1

the model stops when the point value reaches the value 0.1, therefore it works. But what about "less than" ?
If I use mod1.ppb1-0.1 the model stops when the point value reaches the value 0.1, therefore it works. But what about "less than" ?

Posted: 5 years ago Nov 2, 2012, 6:08 AM EDT
Dear Collin,

I was killing my brain with this and finally I have discovered how it works.

Just write:

0.5-(modx.ppby<value)

where x and y denote the index of model and probe evaluation and the value is the desired value. My example:

0.5-(mod1.ppb1<0.02)

Dear Collin, I was killing my brain with this and finally I have discovered how it works. Just write: 0.5-(modx.ppby

Nagi Elabbasi Certified Consultant
Posted: 5 years ago Nov 2, 2012, 4:27 PM EDT
You figured it out obviously. I just want to clarify one thing. The Stop condition terminates the analysis when the stop expression becomes negative. The Boolean operators like >, < evaluate to 0 (False) or 1 (True). That’s why they don’t work as you expected. Your modified expression takes care of that.
You figured it out obviously. I just want to clarify one thing. The Stop condition terminates the analysis when the stop expression becomes negative. The Boolean operators like >, < evaluate to 0 (False) or 1 (True). That’s why they don’t work as you expected. Your modified expression takes care of that.

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