Using more than 6 cores creates WARNING: The viscosity solver didn't converge to the chosen accuracy for HY_Domain01

Describe your realflow bugs
Bobross
Posts: 50
Joined: Wed Mar 03, 2010 8:37 pm

Using more than 6 cores creates WARNING: The viscosity solver didn't converge to the chosen accuracy for HY_Domain01

Postby Bobross » Sat Sep 09, 2017 7:43 pm

I'm running across this really frustrating bug. MY machine has 36 cores (Dual Xeon e5-2686). When I run my Hybrido sim with "use max threads" in settings, I keep getting this error every couple of frames:

WARNING: The viscosity solver didn't converge to the chosen accuracy for HY_Domain01 at frame 1. Even though a solution was found it might not fulfill your expectations. To fix this you can increase the number of iterations in the simulation options.

I did some research and according to Nextlimit Docs I need to increase the MAX iterations. I've set a HUGE number of iterations and that does not solve the problem. However if I set my SIM to use only 6 Cores, everything works fine. Even if I set it to 8 cores I still get this error. Why does that matter?


User avatar
ChristianZ
Posts: 3266
Joined: Sat Sep 09, 2006 11:37 am
Location: CH

Re: Using more than 6 cores creates WARNING: The viscosity solver didn't converge to the chosen accuracy for HY_Domain01

Postby ChristianZ » Sat Sep 09, 2017 8:47 pm

Hi

this question can be answered only by somebody familiar with the code. Nevertheless, I made similar experience with a larger number of threads (dual 8 core) in earlier versions of RF with hybrido. At the end of the day the efficacy of the use of multiple cores rapidly drops after 8 cores or so. If you have more, it does not help you much, unfortunately. But maybe there is a better solution to this problem and I am happy to learn about it.
RF10 standard, System specs: OSX 10.11, MacPro 4.1 2xXeon, GTX980Ti, 64 GB RAM

Bobross
Posts: 50
Joined: Wed Mar 03, 2010 8:37 pm

Re: Using more than 6 cores creates WARNING: The viscosity solver didn't converge to the chosen accuracy for HY_Domain01

Postby Bobross » Sun Sep 10, 2017 6:51 pm

Hi Chistian,

Thank you for the info! Is this specifically related to Hybrido? I don't recall this occurring with Dyverso or Standard particles ever.

Cheers!
Bob

User avatar
ChristianZ
Posts: 3266
Joined: Sat Sep 09, 2006 11:37 am
Location: CH

Re: Using more than 6 cores creates WARNING: The viscosity solver didn't converge to the chosen accuracy for HY_Domain01

Postby ChristianZ » Sun Sep 10, 2017 9:26 pm

Yes, this is a Hybrido issue.
Dyverso in RF10 is a very efficient GPU-enhanced engine with CUDA-cards, even on the Mac. Standard particles have no acceleration by the GPU.
RF10 standard, System specs: OSX 10.11, MacPro 4.1 2xXeon, GTX980Ti, 64 GB RAM


Return to “Realflow bug report”

Who is online

Users browsing this forum: No registered users and 1 guest