Hi Julian, Glad that you are able to move on to doing co-simulations.
If you use a tracker to add acceleration to some owners, then it affects only the next time step. This is to be consistent with other tracker Set methods (such as SetPos) because, well, they technically only affect the simulation once, too. This is also because setting acceleration with trackers is assumed to be used in a co-simulation, and in this case, the acceleration probably changes at each step. If the acceleration modification was to affect indefinitely then it would be the user's responsibility to deactivate it once it is not needed. Of course, this is not necessarily the best or most intuitive design choice and I am open to suggestions. The acceleration prescription can only be added before initialization because it is just-in-time compiled into the CUDA kernels to make it more efficient. They are expected to be non-changing during the simulation and, although fixed prescribed motions are very common in DEM simulation, they are perhaps not suitable to be used in co-simulations. If in your test case the added acceleration seems to have no effect, then it's likely that it is too small, or the DoDynamics is called with a time length that is significantly larger than the time step size. If this is not the case and you suspect it is due to a bug, please provide a minimal reproducible example so I can look into it. Thank you, Ruochun On Monday, May 13, 2024 at 9:05:34 PM UTC+8 [email protected] wrote: > Hi Ruochun, > I've upgraded my hardware and now everything is working fine. > > I'm trying to run a co-simulation with the DEM-Engine where it would be > necessary to pass the acceleration for each particle to the simulation. > From the code, I've seen that there are two options, either by adding an > acceleration or using a prescribed force/acceleration. > > If I read the comments from the code correctly, the acceleration is only > added for the next time step but not constant over the DoDynamics call? > From my tests it looks like the acceleration has no effect on the > trajectory of my particle. > On the other hand, the prescribed acceleration can only be added during > the initialisation, and not between DoDynamics calls. > > Is there an option to add an acceleration to a particle that affects the > particle over the whole DoDynamics call? > > Thank you for help > Julian > On Friday, March 29, 2024 at 9:23:29 PM UTC+1 Ruochun Zhang wrote: > >> Hi Julian, >> >> I see. The minimum CC tested was 6.1 (10 series). 9 and 10 series are a >> big jump and DEME is a new package that uses newer CUDA features a lot. >> Most likely GTX 970 is not going to support them. Quite a good reason to >> get an upgrade I would say, no? >> >> Thank you, >> Ruochun >> On Saturday, March 30, 2024 at 3:38:40 AM UTC+8 [email protected] wrote: >> >>> Hi Ruochun, >>> Thank you for your answer and trying to help me. >>> I have been able to run a simulation in the container using the same >>> image on another GPU machine (a cluster with several NVIDIA RTX 2080Ti w/ >>> 12GB). >>> When I'm trying to run a simulation on my local machine, that I'm using >>> for development purposes with a (NVIDIA GTX 970 w/ 4GB) the simulation >>> crashes. >>> I also tried to run the simulation outside of a container, and the >>> simulation still crashes with the same error. Also other projects using >>> CUDA do run on my local machine. >>> Both machines the cluster and local machine run the exact same CUDA and >>> NVIDIA drivers, so I'm assuming running the simulation inside the Docker >>> Container is not the issue. >>> >>> I'm assuming that there is an issue with the compute capabilities of my >>> local GPU, is there any kind of minimum hardware requirements? >>> >>> Julian >>> >>> On Friday, March 29, 2024 at 7:57:49 PM UTC+1 Ruochun Zhang wrote: >>> >>>> Just to be clear, DEM-Engine runs on a single GPU as well and there is >>>> no difference other than being (around) half as fast. >>>> >>>> Ruochun >>>> >>>> On Friday, March 29, 2024 at 10:58:18 PM UTC+8 [email protected] >>>> wrote: >>>> >>>>> I was able to run a simulation on a different GPU setup, using 2 GPUS. >>>>> Is it not possible to run the DEM-Engine on a single GPU? >>>>> >>>>> On Thursday, March 28, 2024 at 4:55:44 PM UTC+1 Julian Reis wrote: >>>>> >>>>>> Hello, >>>>>> >>>>>> I've tried to setup a Docker Container for the DEM-Engine using the >>>>>> nvidia/cuda-12.0.1-devel-ubuntu22.04 as a base image. >>>>>> I followed the compile instructions from the github-repo and the code >>>>>> compiles fine. >>>>>> When I'm trying to run any of the test-cases tough, the simulation >>>>>> crashes with the following error: >>>>>> Bus error (core dumped) >>>>>> Right after the following outputs for the demo file >>>>>> SingleSphereCollide: >>>>>> These owners are tracked: 0, >>>>>> Meshes' owner--offset pairs: {1, 0}, {2, 1}, >>>>>> kT received a velocity update: 1 >>>>>> >>>>>> Are you aware of any problems like this? >>>>>> >>>>>> Julian >>>>>> >>>>> -- You received this message because you are subscribed to the Google Groups "ProjectChrono" group. 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