Re: [deal.II] Suggestions for "cheap" distributed preconditioner for transient systems?

2020-12-06 Thread Timo Heister
> The task generally contain on the order of 50M to 100M DOFs and are > transient DNS problems. With this you are likely at a point where factorizations (even ILU) not work very well. Even if you can afford a Block ILU, you likely run on 100+ cores, which means the quality of the preconditioner

Re: [deal.II] Clearing a particle properties without getting properties for each particle

2020-12-06 Thread Wolfgang Bangerth
On 12/4/20 6:18 AM, shahab.g...@gmail.com wrote: Not here, but it other functions it would be very useful to be able to map back to the owning particle. I suspect that in that case, it wouldn't be cheaper to loop over particles and map back to particles, but that you could as well loop over pa

Re: [deal.II] Suggestions for "cheap" distributed preconditioner for transient systems?

2020-12-06 Thread Wolfgang Bangerth
On 12/6/20 12:27 PM, blais...@gmail.com wrote: In this case, even using ILU(1) is extremely expensive (e.g. it takes 2X more time than to assemble the matrix and it really doubles up the iteration time). Consequently, we are using ILU(0), which in the present case is performing relatively wel

Re: [deal.II] How to report a progress of KrylovSchur solver

2020-12-06 Thread Wolfgang Bangerth
On 12/5/20 4:09 AM, Loylick wrote: I solve some eigenvalue problem with SLEPcWrappers::SolverKrylovSchur solver. I takes several hours to accomplish the task and I wonder if there is a way to report a progress back from the solver to show for example a number of iterations passed? I don't th

[deal.II] Suggestions for "cheap" distributed preconditioner for transient systems?

2020-12-06 Thread blais...@gmail.com
Hello all, I hope you are all well. This is not strictly a deal.II question, but I thought I could benefit for the huge amount of expertise present on this board. I am currently launching large (at least from my POV) tasks on our HPC cluster. The task generally contain on the order of 50M to 10