Restart

How can the job be restarted or continued?

There are two different ways to restart your job.

If you want to stop the job during the computation and later continue the computation after that stopping point, create a control file.
For example: Your model named TEST_0000.rad for Starter and TEST_0001.rad for Engine.

Then create TEST_0001.ctl in the current folder. In this file, assign the following keyword:

/STOP

Then, Radioss will read this control file, will stop the job and also writes a restart file.

Now to continue the job, create the second Engine file TEST_0002.rad. Simply copy the first Engine file and that is all. Launch this second Engine file and then Radioss will continue the job after your stopping point.
You could also define the frequency restart files in your Engine file beforehand, so that you can later restart your job with any of your restart files.
For example: Your model named TEST_0000.rad for Starter and TEST_0001.rad for Engine.
First, in your Engine file TEST_0001.rad you should define /RFILE/n. For example if you want to create a restart file for each 100 cycles, then do the following:
```
/RFILE/100
100 1 1
```
Then in your current folder, you may have the following restart file depending on your model:
```
TEST_0001_0001_I.rst
TEST_0001_0001_J.rst
TEST_0001_0001_K.rst
TEST_0001_0001_L.rst
TEST_0001_0001_M.rst
TEST_0001_0001_N.rst
…
```
Note: The file name always begins with Restart Letter=I. So, here it begins with TEST_0001_0001_I.rst.

Now to continue your job, the second Engine file TEST_0002.rad should be created. In this Engine file, you could just assign the keyword /RUN.
For example:
```
/RUN/TEST_0001_0001_K/3/K
 100
```

Now launch this second Engine file, Radioss will continue the job after the point of TEST_0001_0001_K.rst.

Note: Run Numbers are defined below:

TEST_0001_0001_I.rst     Run Number = 1
TEST_0001_0001_J.rst     Run Number = 2
TEST_0001_0001_K.rst     Run Number = 3
TEST_0001_0001_L.rst     Run Number = 4
TEST_0001_0001_M.rst     Run Number = 5
TEST_0001_0001_N.rst     Run Number = 6
…

To continue the run:

If you need to continue the calculation without modify any definitions in Starter, run the (i+1)th Engine file (Runname_000(i+1).rad).
For Example:
- run Starter: TEST_0000.rad
- run the first Engine: TEST_0001.rad
- run the second Engine: TEST_0002.rad > to continue the run after TEST_0001.rad
  Radioss could restart the calculation from the last Restart file which was created by running TEST_0001.rad.

Is it possible to stop a computation that is running after writing a RESTART file?

It is possible to do this by writing a control file in the same directory as the run data.

In case of a run number nnnn (/RUN/Runname/nnn in the Radioss Engine input file), you have to create a file called Runname_nnnn.ctl and write the following line in it:

/STOP

Radioss Engine ends and a RESTART file is written.

The others options available with control files are described in the Control File (C-File) section.

What should I do if Radioss Engine does not start; it seems there is a problem with the RESTART file (Runname_0000_0000.rst)?

Check that the RESTART file Runname_0000_0000.rst (written by Starter) that appears in the directory where Radioss Engine has been run.

Is it possible to write several RESTART files during the same run, without over-writing them each time?

You have to write the option /RFILE/n in the Radioss Engine input file Runname_run#.rad:

n refers to the number of different RESTART files that will be kept. The n RESTART files will get different names Runname_0001_0000_[C].rst1 with an extension using a letter: for example, the first RESTART file will be called Runname_0001_0000_I.rst; the second RESTART file will be called Runname_0001_0000_J.rst and so on. The n+1th file will also be called Runname_0001_0000_I.rst and will overwrite the first file. This sequence is repeated.

It is possible to write up to 18 different RESTART files within the same run.

In order to restart from a file in the next run, you will have to specify in the Runname_run#.rad input file the next run, the letter defining the RESTART file into option /RUN.

For instance, for restarting with file Runname_0001_0000_J.rst:/RUN/Runname/2/J.

Reference

Let Runname_0001_cpu#_[C].rst for SPMD version, with cpu# varying from one to the number of processors which are used.