On 9/27/21 1:43 PM, Kyle Schwiebert wrote:
I'm trying to replicate the simulation described in this paper
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwias-berlin.de%2Fpeople%2Fjohn%2FELECTRONIC_PAPERS%2FJoh04.IJNMF.pdf&data=04%7C01%7CWolfgang.Bangerth%40colostate.edu%7Ce97881b432a742a2b53008d981ef1a37%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637683686653742835%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=dDqBEMcMDHgOSMr4G2McKiWUmifKo5sSZpc3ReFfUQ8%3D&reserved=0>.
How could I compute the integrals in equations 4 and 5? I'm sure it's
covered in the tutorial, but I couldn't find it after searching in
several different steps in the tutorial. Could someone please point me
to an example in the tutorials where this type of computation with a
computed solution? The only examples I could find seem to only discuss
computing L2, or H1 errors with a special function that avoid manually
computing the integral. Is the easiest thing to do as is done in the
matrix assembly?
Kyle,
in essence you just have to loop over all cells and integrate up the
quantity you have in the formula for a given choice of v_l and v_d. This
works in a similar way to this example here where we compute the angular
momentum:
https://github.com/geodynamics/aspect/blob/master/source/simulator/nullspace.cc#L357-L459
Finally, how would one initialize the vectors v_l and v_d? Could it be
done easily with an appropriate AffineConstraints object?
As long as you satisfy the boundary conditions, it's your choice. So you
could, for example, start with a zero vector, evaluate boundary values
as indicated on the boundary in question, and then just go through the
constraints you get as a result and apply them to your zero vector (via
AffineConstraints::distribute(), applied to the zero vector). That would
probably be what I'd do.
Or you just take v_l/v_d as functions that are analytically described
(i.e., that are not finite element functions to begin with).
Best
W.
--
------------------------------------------------------------------------
Wolfgang Bangerth email: [email protected]
www: http://www.math.colostate.edu/~bangerth/
--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see
https://groups.google.com/d/forum/dealii?hl=en
---
You received this message because you are subscribed to the Google Groups "deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/dealii/96b0b904-d281-8241-0777-2fdbfdc28fca%40colostate.edu.
