Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
How are pointwise constraints implemented?
Posted 16.06.2020, 10:24 GMT-4 General, Equation-Based Modeling Version 5.5 1 Reply
Please login with a confirmed email address before reporting spam
Hello,
I understand how we can add weak constraints by explicitly adding Lagrange multipliers and multiplying by the constraint expression. I also understand how mathematically we can constrain a degree of freedom by modifying the matrix column attached to it, but I do not think that is what Comsol is doing.
In the Comsol documentation, it states that in the pointwise constraint, the Lagrange multipliers are implicitly defined and eliminated with the degrees of freedom. What is meant by implicitly defined and eliminated?
Thank you,
Alex
Please login with a confirmed email address before reporting spam
Just found a very interesting Comsol blog explaining the difference between pointwise and weak constraints:
https://www.comsol.com/blogs/implementing-the-weak-form-with-a-comsol-app/#equation1
Cheers,
Alex