The point here is that V is an unknown quantity, which must be solved for using the Integral constraint involving the gamma term.

OK, I didn’t get that from reading the text the first time. I don’t have specific experience for this kind of constraint, but you may want to start by searching the forum with “nullspace” as keyword, and start reading recent posts about that.

I found the following post that seems to solve a similar type of problem https://fenicsproject.org/olddocs/dolfin/2018.1.0/python/demos/singular-poisson/demo_singular-poisson.py.html Unfortunately, the solution is in fenics instead of fenicsx, so I don’t know how to convert it. (I am a complete be…

Having seen your recent posts in Issues Solving Pure Neumann Problems in dolfinx - #7 by Daniel.Baker , I’d like to remark that one difference between the problem here and the one in the other post is that here you actually have two constraints: the integral constraint on Gamma_2 the fact that the …

I agree entirely with your observation. Having said that, it is perhaps worth being more explicit about the second constraint. Let’s choose an arbitrary point x_0 in Gamma_2. Then the second constraint says that the difference u(x)-u(x_0)=0 for every point x in Gamma_2. Thus, if there are N DOFs for…

I will try to reply to comments from @dokken that seem to be relevant to the problem I posed at the top of this thread. I have looked through his suggestions, and I think that, in principle, the information he provided could be used to solve the above problem, if I only understood how to implement i…

This was my bad. Full documentation of the equations is cited in the demo_stokes in the link https://arxiv.org/pdf/2001.10639.pdf It might help to put this reference at the top of the demo. The following reference is also helpful https://hal.science/hal-04077986/document

A presentation of DOLFINx_mpc as a framework was done at FEniCS 21: https://fenics2021.com/slides/dokken.pdf and at Sorbonne/D’Alembert institute fall of 2023: https://www.youtube.com/watch?v=4LSWOdyiGH8&ab_channel=InstitutJeanLeRondd’Alembert

I have dolfinx up and running. How do I find dolfinx_mpc so I can install it? Sorry to have to keep asking these questions. I should be starting to know this stuff by now. Got it! I’m up and running.

Implementing a potential problem with a current condition

variational formulation

francesco-ballarin May 1, 2024, 4:19pm 8

@Daniel.Baker and @dokken may want to continue here the discussion from Issues Solving Pure Neumann Problems in dolfinx - #8 by dokken

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Implementing a potential problem with a current condition

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