Multigrid Preconditioner Crashes

Hello,

I am using adaptive refinement with the multigrid preconditioner and I have found that after each iteration, the program will stop without giving any indication of an error. I save the mesh after each iteration, so I can rerun the program and improve the mesh manually one iteration at a time, but I would like to know how to fix this issue. When running the program, I can see that the bilinear and linear forms are being assembled, but the program crashes when it gets to building the preconditioner. I have not had this problem with any other preconditioners. If could you help me figure this out, I would be appreciative.

Thanks

Hi,
can you send a minimal example reproducing that behaviour? In the example from the itutorials the multigrid preconditioner is working.
ngsolve.org/docu/latest/i-tutorials/unit...vity/adaptivity.html
Best
Christopher

I have attached an example. I find that it will successfully complete one iteration, but will unexpectedly stop as soon as assembly is completed during the second iteration.

Thanks

I see, thanks for reporting this, there seems to be some needed functionality for complex geometric multigrid missing for the HCurl space. We will investigate this. For the time being you could use the bddcc preconditioner, it needs more iterations but every iteration is faster, so for me it's about the same speed as the multigrid.
I'll let you know when the multigrid is fixed.
Best
Christopher