running out of memory
I have an Ubuntu partition with 20GB. I get the "new" error when running a mesh with 4 million cells. I'm not sure what my swap is.
Should I change the partition size of the ubuntu installation? or is tehre a way to change the swap file size inside Ubuntu? |
Hi,
Can you copy your error message here ? |
In my case, I have this error message :
Code:
Shell refinement iteration 9 (My configuration : 4 cores at 2,4 GHz ; 6 go of memory and 100 go of disque space) |
I tried to execute the same simulation on another computer and I had this errors message :
Code:
Shell refinement iteration 0 Code:
Shell refinement iteration 0 |
Any ideas ?
|
Hi,
when I had this error message I usually run out of RAM. As a rule of thumb one can say that you shouldn't use more than 1 M cells per 1 GB of RAM (which is the absolute maximum). In your case I see you have already 10902074 cells so way too much for your hardware (6 GB of RAM). The other messages you posted are referring to the same issue. Hint: limit the maximum number of cells in the sHMD to lets say 5M in your case or even less (entity: maxGlobalCells in sHMD). Be aware that the total number of cells might still be more then the number of cells specified here, for the refinement is aborted after sHM is hitting the boundary. E.g. maxGlobalcells set to 1M you have a background mesh of 500k and due to cutting ut a geometry 50k cells are removed and then first level of refinement starts and you end up with 950k he continues refinement and in the next step you might end up with 2 Mio which is twice the number of what you specified. But then he will stop refinement. SO: to reach the maximum number of cells your RAM can handle you watch the last refinement steps in the log of sHM and look for the refinement level which has less cells then you want to have in total and then you set maxGlobalcells to a value less than this and hope it was ok. hope that helps regards |
Thanks Colin, I figured out I had to increase the swap size and posted the solution here. I also have reduced the areas of refinement based on distance.
http://www.cfd-online.com/Forums/ope...y-crashes.html |
Hi,
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"ColinB"
What proportion have you between maxLocalCells and maxGlobalCells ? For example maxLocalCells => 1 000 000 maxGlobalCells => 2 000 000 |
As far as I understood this "ratio" is dependant on the number of processors
you are using and the number of cells specified in here (maxLocalCells) is the number of maxGlobalCells divided by the number of processors. However I'm not 100% sure. So usually for mesh generation with 1 core the number is then the same like maxGlobalCells with 2 cores it is half and so on. |
Ok, Thanks colinB.
I will try this method ;) |
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What is the way to work out this ratio? |
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