Restarting Simulations

Altair Forum User

Firstly I apologies for what is probably a really simple question but the solution is eluding me.

I am running some impact simulations in Radioss after pre processing in hypermesh and setting the conditions in hypercrash. The simulations work fine, but they take rather a long time so I was wondering if I could pause them and restart later?

I see that the solver writes a .rst file every so often but nothing I do seems to get it to continue. I am using radioss block 100 if that makes any difference.

Thanks for any help

Andy_20955

Hi,

To stop and start simulation you have to create a control file. See this section of Radioss help,

Home topic Reference Guide > Block Format > Other Files: Control File (C-File)

The control file has the .ctl extension with the same prefix as you engine file.

So if your engine file is name, mymodel_0001.rad, then you control file would be mymodel_0001.ctl.

Create the *.ctl file and put the word /STOP on the first line and save file. Radioss looks for the *.clt file while running and will then stop. When it stops RAdioss will create a *.rst which is restart file.

Then if you need to start you simulation again, create a new engine file increasing the number by 1. Easiest thing is to,

copy your mymodel_0001.rad file to the name mymodel_0002.rad.

Then edit the mymodel_0002.rad file and change the line,

/RUN/mymodel/1/ to /RUN/mymodel/2/

Last, to restart your run use the -engine option and give your new engine file like this,

radioss -engine mymodel_0002.rad

Andy_20955

I forgot to mention if you are using Radioss 11 you can launch jobs through the new solver GUI and there are options to create the control file and /STOP from within the GUI. On Linux you start the GUI using, radios -gui. On windows you start the GUI from using the start menu shortcuts. You have to check the box that is marked solver control.

Altair Forum User

That's awesome, thanks a lot.

Altair Forum User

you could also use 'RERUN' option in the engine deck. just change the 'RUN' to 'RERUN' and then solve it. it uses the final restart file(s) and goes on from there.