Stokes iTutorial

ddrake
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7 years 2 months ago - 7 years 2 months ago #586 by ddrake

Stokes iTutorial was created by ddrake

Hi
I was working through the Stokes iTutorial and noticed an issue.

In input blocks 9 and 10, I get an error:

Code:

V = H1(mesh, order=2, dirichlet="wall|inlet|cyl")
V.order[TRIG]=3

Code:

AttributeError: 'ngsolve.comp.H1' object has no attribute 'order'

I eliminate the AttributeError if I change this line to:

Code:

V.SetOrder(element_type=TRIG, order=3)

But instead of the expected output, I get this:

V.ndof = 1702 , Q.ndof = 2382

Code:

---------------------------------------------------------------------------
RuntimeError                              Traceback (most recent call last)
<ipython-input-20-6e302700a473> in <module>()
      5 Q = L2(mesh, order=1)
      6 X = FESpace([V,V,Q])
----> 7 gfu = SolveStokes(X)
      8 velocity = CoefficientFunction(gfu.components[0:2])
      9 Draw(velocity, mesh, "vel")

<ipython-input-6-6f8714cf1452> in SolveStokes(X)
     16     res = gfu.vec.CreateVector()
     17     res.data = -a.mat * gfu.vec
---> 18     inv = a.mat.Inverse(freedofs=X.FreeDofs(), inverse="umfpack")
     19     gfu.vec.data += inv * res
     20     return gfu

RuntimeError: UmfpackInverse: Numeric factorization failed.

Best,
Dow

Last edit: 7 years 2 months ago by ddrake. Reason: Clarification

ddrake
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7 years 1 month ago #605 by ddrake

Replied by ddrake on topic Stokes iTutorial

The current version of this tutorial is working as expected.

Thanks!
Dow

christopher
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7 years 1 month ago #609 by christopher

Replied by christopher on topic Stokes iTutorial

There is a cell where there is a note that with that choice of spaces the problem is instable. In that case the umfpack inverse fails. We correct that afterwards with the correct choice of spaces.

Best
Christopher

The following user(s) said Thank You: ddrake

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