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How are pointwise constraints implemented?
Posted Jun 16, 2020, 10:24 a.m. EDT General, Equation-Based Modeling Version 5.5 1 Reply
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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
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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