Re: [deal.II] Number of DOFs after refinement depends on number of MPI processes (p:d:Triangulation)

2019-06-20 Thread Wolfgang Bangerth 
On 6/20/19 9:19 AM, Stephen DeWitt wrote:
> I'm running matrix free calculations using a 
> parallel::distributed::Triangulation (loosely based on step-48). One thing 
> that I've noticed is the the final number of DOFs at the end of a simulation 
> vary slightly depending on my number of MPI processes. For example, one run 
> on 
> 16 cores finished with 2,988,700 DOF and nominally the same run on 512 cores 
> finished with 2,988,864. Is this to be expected?

If the number of cells is also different, then yes. For the same number of 
cells, you need to get the same number of DoFs, so the number of cells is the 
normative question you need to investigate.

If you do use adaptive mesh refinement, then just as you mention there are 
heuristics that sometimes do or do not lead to certain cells to be refined. 
For example, computing the threshold for the local error indicators above 
which a cell should be refined is one algorithm that might slightly depend on 
the number of processes you use.

Best
  W.


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www: http://www.math.colostate.edu/~bangerth/

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Re: [deal.II] Re: deal.II User and Developer Workshop: August 6-9, 2019

2019-06-20 Thread Wolfgang Bangerth 
On 6/20/19 11:32 AM, Stephen DeWitt wrote:
> Would it be possible to record some or all of the presentations at the 
> workshop? Due to a conflict I won't be able to attend, but I would still be 
> very interested in hearing the talks/discussions at the workshop.

Nice idea -- let me investigate!
Best
  W.


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Re: [deal.II] Re: deal.II User and Developer Workshop: August 6-9, 2019

2019-06-20 Thread Alberto Salvadori 
> Dear Wolfgang and Timo,

I believe this is a very good idea. Since I cannot attend the workshop I do 
support Steve's request.

Cheers 
Alberto

Alberto Salvadori
Associate Professor 
DIMI, University of Brescia, Italy


> On 20 Jun 2019, at 19:32, Stephen DeWitt  wrote:
> 
> Dear Wolfgang and Timo,
> Would it be possible to record some or all of the presentations at the 
> workshop? Due to a conflict I won't be able to attend, but I would still be 
> very interested in hearing the talks/discussions at the workshop.
> 
> Best,
> Steve
> 
>> On Wednesday, April 10, 2019 at 12:18:43 AM UTC-4, Wolfgang Bangerth wrote:
>> 
>> Dear deal.II users and developers, 
>> 
>> The 
>> Seventh deal.II Users' and Developers' workshop 
>> will be held August 6-9, 2019 in Fort Collins, Colorado, USA. The 
>> intent of this workshop is to discuss applications and tools using 
>> deal.II, as well as future directions of the library itself. 
>> 
>> We invite proposals for talks and discussion topics by users and 
>> existing developers in the following areas: 
>>   - Use cases and applications of the library. 
>>   - What users think would be useful directions for the library to go into, 
>> things that are missing, and possibly getting people together who can 
>> help 
>> implement those parts. 
>>   - Newer parts of the library (e.g., geometry descriptions, large parallel 
>> computations, etc.) and how these could help in your programs. 
>> A significant part of the time will be set aside for "hackathon"- or "code 
>> jam"-style sessions where people can ask questions, work on their codes 
>> with others, and receive help from experienced users. 
>> 
>> Registration: 
>> For workshop and registration information, see 
>>https://dealii.org/workshop-2019/ 
>> 
>> Deadline for registration: May 5, 2019. Participation is capped at 
>> around 60. 
>> 
>> Travel support: 
>> A limited amount of (domestic) travel support is available courtesy of the 
>> National Science Foundation, and will be given on a first come first serve 
>> basis, with preference to undergraduate and graduate students. If you need 
>> support, please state so in your registration. 
>> 
>> The organizers 
>>Wolfgang Bangerth (Colorado State University, bang...@colostate.edu) 
>>Timo Heister (University of Utah, hei...@sci.utah.edu) 
>> 
>> -- 
>>  
>> Wolfgang Bangerth  email: bang...@colostate.edu 
>> www: http://www.math.colostate.edu/~bangerth/ 
>> 
> 
> -- 
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[deal.II] Re: deal.II User and Developer Workshop: August 6-9, 2019

2019-06-20 Thread Stephen DeWitt 
Dear Wolfgang and Timo,
Would it be possible to record some or all of the presentations at the 
workshop? Due to a conflict I won't be able to attend, but I would still be 
very interested in hearing the talks/discussions at the workshop.

Best,
Steve

On Wednesday, April 10, 2019 at 12:18:43 AM UTC-4, Wolfgang Bangerth wrote:
>
>
> Dear deal.II users and developers, 
>
> The 
> Seventh deal.II Users' and Developers' workshop 
> will be held August 6-9, 2019 in Fort Collins, Colorado, USA. The 
> intent of this workshop is to discuss applications and tools using 
> deal.II, as well as future directions of the library itself. 
>
> We invite proposals for talks and discussion topics by users and 
> existing developers in the following areas: 
>   - Use cases and applications of the library. 
>   - What users think would be useful directions for the library to go 
> into, 
> things that are missing, and possibly getting people together who can 
> help 
> implement those parts. 
>   - Newer parts of the library (e.g., geometry descriptions, large 
> parallel 
> computations, etc.) and how these could help in your programs. 
> A significant part of the time will be set aside for "hackathon"- or "code 
> jam"-style sessions where people can ask questions, work on their codes 
> with others, and receive help from experienced users. 
>
> Registration: 
> For workshop and registration information, see 
>https://dealii.org/workshop-2019/ 
>
> Deadline for registration: May 5, 2019. Participation is capped at 
> around 60. 
>
> Travel support: 
> A limited amount of (domestic) travel support is available courtesy of the 
> National Science Foundation, and will be given on a first come first serve 
> basis, with preference to undergraduate and graduate students. If you need 
> support, please state so in your registration. 
>
> The organizers 
>Wolfgang Bangerth (Colorado State University, bang...@colostate.edu 
> ) 
>Timo Heister (University of Utah, hei...@sci.utah.edu ) 
>
> -- 
>  
> Wolfgang Bangerth  email: bang...@colostate.edu 
>  
> www: http://www.math.colostate.edu/~bangerth/ 
>
>

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[deal.II] Number of DOFs after refinement depends on number of MPI processes (p:d:Triangulation)

2019-06-20 Thread Stephen DeWitt 
Hello,
I'm running matrix free calculations using a 
parallel::distributed::Triangulation (loosely based on step-48). One thing 
that I've noticed is the the final number of DOFs at the end of a 
simulation vary slightly depending on my number of MPI processes. For 
example, one run on 16 cores finished with 2,988,700 DOF and nominally the 
same run on 512 cores finished with 2,988,864. Is this to be expected? My 
working assumption has been that there are a number of heuristics that go 
into "smoothing" the refinement of the mesh and that some/all of these only 
operate on the local part of the mesh. Is that the case? Or should I be 
concerned that I have a subtle issue in my code? Nothing changes 
qualitatively between simulations with different numbers of cores, but of 
course there is a very small difference in the solutions due to the 
different meshes.

Thanks,
Steve


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Re: [deal.II] deal.II coupling using preCICE

2019-06-20 Thread Wolfgang Bangerth 


David (and all):

> Two questions:
> * We link to applications that build on deal.II under the "Applications" 
> tab
>     at the top right of https://dealii.org/ . Should we link to preCICE as
> well?
> 
> 
>   We would be very happy about a linking. Thanks in advance.

Great. Do you want me to link to https://www.precice.org or to anything more 
deal.II-related on your sub-pages? Whatever URL you give me I'll link to.


> * Are there any publications that use this coupling and that we could 
> list at
> https://dealii.org/publications.html 
> 
> 
> 
> The recent post/project origanted from a student project without a thesis. 
> But 
> there have been previous student theses at the University of Siegen, which 
> used deal.II and preCICE. Unfortunately, they are not online available. I 
> attached BibTex files of both, in case you would like to list them anyway.

Yes, we take them all. Thanks for the bib entries, I've added them to the list 
(as a pull request for now, but they will eventually show up on the website as 
well).


> The 
> current state of our project is -in terms of deal.II- very basic and there 
> might be a thesis in the future dealing with an extension. We will let you 
> know about completed thesis in this area.

Much appreciated. Keeping this list as complete as possible is important to us!

Thanks
  Wolfgang



-- 

Wolfgang Bangerth  email: bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

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[deal.II] deal.II Newsletter #84

2019-06-20 Thread Rene Gassmoeller 
Hello everyone!

This is deal.II newsletter #84.
It automatically reports recently merged features and discussions about the 
deal.II finite element library.


## Below you find a list of recently proposed or merged features:

#8322: Complex project_boundary_values_curl (proposed by dangars) 
https://github.com/dealii/dealii/pull/8322

#8320: Fix compilation on MSVS 2017 (proposed by StefanoDominici89; merged) 
https://github.com/dealii/dealii/pull/8320

#8319: step-67: explicit time integration with matrix-free implementations 
(proposed by kronbichler) https://github.com/dealii/dealii/pull/8319

#8318: Remove deprecated tria_boundary*.h (proposed by kronbichler; merged) 
https://github.com/dealii/dealii/pull/8318

#8308: Correct reading in MPIEXEC_PREFLAGS containing spaces (proposed by 
kronbichler; merged) https://github.com/dealii/dealii/pull/8308

#8305:  Unify coarsening properties for cell characteristics. (proposed by 
marcfehling; merged) https://github.com/dealii/dealii/pull/8305

#8144: update python tools scripts (proposed by tjhei; merged) 
https://github.com/dealii/dealii/pull/8144

#8058: Step-65: Handling expensive manifolds (proposed by kronbichler; merged) 
https://github.com/dealii/dealii/pull/8058


## And this is a list of recently opened or closed discussions:

#8323: Different results in the test for Nedelec and NedelecSZ (opened) 
https://github.com/dealii/dealii/issues/8323

#8321: Documentation of GridTools::extract_boundary_mesh is incorrect (opened) 
https://github.com/dealii/dealii/issues/8321

#7928: 'FEValuesViews': the symbol to the left of a '::' must be a type  (MSVC) 
(closed) https://github.com/dealii/dealii/issues/7928

#6782: Re-remove tria_boundary*.h (closed) 
https://github.com/dealii/dealii/issues/6782

#6663: Tutorial for TransfiniteInterpolationManifold (closed) 
https://github.com/dealii/dealii/issues/6663

#5506: Handling expensive manifolds (closed) 
https://github.com/dealii/dealii/issues/5506


A list of all major changes since the last release can be found at 
https://www.dealii.org/developer/doxygen/deal.II/changes_after_8_5_0.html.


Thanks for being part of the community!


Let us know about questions, problems, bugs or just share your experience by 
writing to dealii@googlegroups.com, or by opening issues or pull requests at 
https://www.github.com/dealii/dealii.
Additional information can be found at https://www.dealii.org/.

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