Follow tutorial1 up to the point where you are ready to save the sample after it has been built.  We assume that you already have the MessageServer and the jamm compute node running somewhere, either on the local machine or some remote machine.  If not, please consult the installation instructions to see how to start these programs.  Start the scheduler by typing java –jar JaSCH.jar.  You should see…

 

 

Click on the Refresh button to populate the table with nodes.  Select a node from the list and click on the Schecule button to schedule a job.  The following widget appears…

 

 

 

Click on GetSampleFile to read in the cml file you built in tutorial1 and open the file.  The Schedule button will become enabled.  Click on the Schedule button and the following widget appears…

 

 

The Node schedule widget allows you to associate specific regions in the input file to specific compute nodes.  In this version of JaMM this is not enabled, so just select OK.  NOTE: if no nodes are listed in the second column then the type of region (magnetic, dielectric/ferroelectric, or neither) does not have an associated compute node program and nothing will be computed.  In other words, the magnetic regions in your sample must be sent to a compute node running the jamm.jar executable.  After clicking on the OK button the Schedule widget appears…

 

 

You must first configure the job before submitting it.  Click on the AddConfiguration button.  The JaMES configuration widget appears.  JaMM is being added to a package that includes a numerical solution of Maxwell’s Equations which we have called JaMES for Java Maxwell Equations Solver.

 

 

For now, enter in your name as the username.  The only other parameter you may wish to change for this run is the Basename.  The Basename is the root of the generated filename when the output files are written to the remote node computer.  Let’s leave that as test in this example.  You could also change the Random seed to examine the affect of different starting random configurations. In this example we will have no applied magnetic field. Click on the OK button.  The Acquisition parameters widget appears…

 

 

The settings here are crucial for the success of the simulation.  The number of steps should be chosen to be conservatively larger than necessary to ensure convergence.  This, of course, depends on the numerical method to be chosen in the next step, as we will see.  In the next step we will choose an adaptive step size Runge-Kutta method.  We can reasonable expect the run to complete in a few hundred cycles, so set the Number of Steps to 2000.  The Timestep depends on the method and what information you are trying to glean from the simulation.  Typically you want a conservatively short timestep to ensure then method does not fail.  Let’s try a Timestep of 1x10-12 s.  The Output Frequency is how often you want intermediate results written to a file on the remote computer.  If you are planning a “movie” of a reversal you may wish to write every ten iterations.  For this example we only want to see the final result, so set the Output Frequency to 0 and set the Output on Termination to true.  This means that when the job is finished the final configuration will be written to a file.  Click on the OK button.  The Output properties widget appears…

 

 

This widget controls which properties are written to the output file.  Note that not all properties are necessarily available to be written, for example, there is not electric potential in a micromagnetics run.  Choose true for Magnetization? and then click on OK.  The LLG parameters widget appears…

 

 

This widget controls various parameters specific to the numerical solution of the LLG equation.  Various numerical methods are available and more are being added.  Let’s stick with the defaults.  The LLG decay controls the damping part of the LLG equation.  0.5 is a fairly large damping coefficient, but is reasonable for obtaining equilibrium configurations.  Simulations trying to understand magnetization reversal should use a damping coefficient appropriate to the material.  The Demag update frequency in the frequency with which the demagnetizing field is updated during the simulation.  THIS FEATURE IS CURRENTLY NOT USED. THE DEMAG FIELD IS UPDATED EVERY TIME STEP.  Finally, JaMM does do periodic boundary conditions.  For now, choose none. Click OK.

 

 

The Submit button on the Schedule widget is now active. Click on the Submit button.  The job is submitted to the remote computer.  Click on the Status button in JaSCH.  The status widget should appear…

 

 

Click on the Refresh button periodically to watch the process of the job on the remote computer.  You can suspend/resume execution by selecting the job from the list and then clicking the appropriate buttons.  You can also permanently stop (kill) the remote job.  The Clear button clears the stopped jobs from the MessageServer list and the Write button forces a writing of an intermediate result to the remote computer.  When the job is done the Status widget appears with a red background in the table.  When the job is complete click on the Done button.  Your job is now complete.  Next, you need to retrieve the files from the remote computer so that you can use a visualization tool to see the results.

 

 

To retrieve the files click on the RemoteFileIO button in the JaSCH widget.  The following widget appears…

 

 

You can retrieve (or delete) files from the remote computer by selecting the file from the table and click on the Get (or Delete) button.  Once you have retrieved the file you have completed the running of the job and you can use the visualization tool, JaSEE, to analyze the output.