On Sun, 15 Jan 2017, Mike Marchywka wrote:

> http://am2012.math.cas.cz/proceedings/contributions/madden.pdf

This is actually kind of dumbfounding: Fix Your Solutions With One
Weird Trick That Numerical Analysists Hate!  I wonder if there's any
extension to 2D/3D?  Any way to express the algorithm as a single weak
formulation that gives you a solution function rather than a weird two
phase solve that gives a set of solution points?

IIRC a lot of FEM stabilization methods history could be (over)
simplified as "(1) see what works for finite differences on uniform
grids, (2) figure out how to copy it in a finite element setting, (3)
figure out how to make it more sensible under some theoretical
criteria, which often makes it better or more generalizable in
practice too".  But most of the important step (1) work happened
before I was born, yet this paper (well, the 2007 paper they cite)
sounds like a real fresh entry in that vein.

> Interested if anyone cares to comment on current status and libmesh facilities
> that may be relevant or if this is just a "lmgtfy" case. I gathered the normal
> approaches were largely things that modify the apparent diffusivity
> which does not seem to be a lot different from anything else you may add to a 
> system.

Most numerical stabilization schemes do boil down into "adding
diffusivity" one way or another, but it's not as hokey as it sounds.
The trick is to do what's called "consistent stabilization": in the
finite element sense, consistent stabilization changes the weak
formulation in such a way that the exact solution to the problem is
still a solution to the stabilized weak problem.  This (as well as
making sure the effects are anisotropic in 2D/3D) is generally enough
to get you a good solution (even an exact interpolant, in 1D!) without
smearing out real features.
---
Roy

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