Hi Ronghong, I have a version of the MsFEM for systems but this project is not published yet so I hesitate to share code at this stage (also the code is not very clean yet). I will be happy though to guide you with the code design and even with some helpful code snippets. If you are interested let's get in touch by email. This is my homepage with contact info <https://www.clisap.de/research/a:-climate-dynamics-and-variability/crg-numerical-methods-in-geosciences/team-members/konrad-simon> .
Best, Konrad On Monday, November 19, 2018 at 2:33:39 PM UTC+1, Ronghong Fan wrote: > > Dear Konrad, > > Thanks for your reply. Now I just want to solve two separate scales, which > is just a start. > I read the book "Multiscale Finite Element Methods. Theory and > Applications by Thomas Hou" written by Yalchin Efendiev and Thomas Y. Hou. > Maybe you have read it. > I know this multiscale finite element method is different with variational > multiscale finite element method. > So if there is no problem, could you please send me a demo about > multiscale FEM? > > Thank you in advance. > > Cheers, > Ronghong > > On Sat, Nov 17, 2018 at 5:21 AM Konrad <ksimo...@gmail.com <javascript:>> > wrote: > >> Dear Ronghong Fan, >> >> Yes, I implemented several versions. The question I asked above got >> resolved as explained above. If you have a specific question feel free to >> ask, I will help if I can. Keep in mind that Multiscale FEMs are not >> generic, only work in certain (scaling) scenarios and do not work so well >> if you do not have scale separation (at least not in their standard >> version). >> >> Let me know about questions. >> >> Cheers, >> Konrad >> >> On Wednesday, November 14, 2018 at 3:50:27 AM UTC+1, Ronghong Fan wrote: >>> >>> Dear Konrad, >>> Do you have some progress about Multiscale Finite Element Method with >>> dealii? >>> I am very interested in mfem too and want to use dealii to implement. >>> >>> >>> On Thursday, August 30, 2018 at 7:27:21 PM UTC+8, Konrad wrote: >>>> >>>> On Wednesday, August 29, 2018 at 5:25:29 PM UTC+2, Wolfgang Bangerth >>>> wrote: >>>>> >>>>> >>>>> I think that's actually an important point you are making here, maybe >>>>> inadvertently: You have as many *meshes* as there are coarse cells. >>>>> >>>>> Now, just refining the global mesh a number of more times gives you >>>>> another global mesh, but it does not give you a mesh for each coarse >>>>> cell. >>>>> >>>>> In my deal.II classes, I've had students solve problems like yours and >>>>> they typically just build one new triangulation for each coarse mesh >>>>> cell, then attach a DoFHandler to it, and solve problems on them. That >>>>> is likely not very efficient if you want to solve real problems, but >>>>> it's good enough for small testcases and it allows for easy >>>>> parallelization using threads. >>>>> >>>>> On the other hand, if you were to build a global DoFHandler on the >>>>> refined mesh, you'd have to define what to do with those DoFs that lie >>>>> outside the patch (that results from a single coarse mesh) you are >>>>> currently considering. You'd likely want to set these to zero, but >>>>> they're still there, and the resulting patch problem will be large. >>>>> It's >>>>> also much more difficult to do things in parallel because now you have >>>>> one global (fine) mesh that you want to use for multiple things at the >>>>> same time. >>>>> >>>> >>>> This is exactly the way I decided to do it. As you say, it is probably >>>> not the most efficient way but easy to thread (and maybe even easy to >>>> bring >>>> on different nodes on a cluster). Thanks again for your comments. >>>> >>>> Cheers, >>>> Konrad >>>> >>> -- >> 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 dealii+un...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > -- 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 dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
