On 6/2/21 8:26 AM, Simon wrote:
-My second question is why for my dim=3 case the function call takes much
longer as in the dim=2 case? In the latter I have much more DoFs.
My guess was that the number of DoFs is the essential quantity but this is
obviously not the case.
Sparse direct solvers need to form an elimination tree, and the work
associated with that is crucially determined by (i) the breadth of that tree ,
(ii) the number of entries per row. In 3d, you have substantially more entries
per row, and the breadth of the tree is larger. As a consequence, the
complexity of solving a linear system with a sparse direct solver is different
in 2d and 3d. See also the notes here:
https://www.math.colostate.edu/~bangerth/videos.676.34.html
In other words, sparse direct solvers are not nearly as attractive in 3d as
they are in 2d.
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/5de35767-2709-272a-ad31-64f25ec6dc44%40colostate.edu.
