Using the Package

There is a specific workflow which must be adhered to in order to use the package.

  1. First, you must specify the cpw geometry parameters. I have specified a text file called cpw_parameters.txt where I update the values, and in a preprocessing script I simply read the parameters in from that file. The text file which specifies the parameters looks something like

    w = 10e-06
t = 50e-09
l = 8.194e-03
pen = 200e-09
omega = 7.3e09
Z = 50

  2. Next, you must define a preprocessing script which sets the cpw geometry parameters, and determines the current density of the structure based on those parameters. See the example current_density.py to get a better idea on how to achieve this.

  3. With the current density calculated and stored in a parameter file, you can now remoteley connect to a host computer and run COMSOL. One way to achieve this is to define a python script such as the example remote_interface.py, and run that script from the terminal window with the command python remote_interface.py.

    There are a number of host computers available at ucl. Two common ones are vienna and monaco, found in the EEE department. To ssh directly into these machines, in a terminal window you would type the command::

    ssh <USERNAME>@ee.ucl.ac.uk

There is also gade.phys. However, this is my personal machine, and is often in use.

This would remoteley give you access to the machine from your own computer. This package does all of this for you. When you first use the package, you will need to specify your username annd the host network (ee.ucl.ac.uk), and the ssh_command library includes functionality to gennerate a secure ssh key and upload this to the host computer.

Bear in mind, if you want to ssh into a ucl machine when you are outside UCL, you will be blocked by the firewall. To get round this, you need to install the ucl vpn. This can be found on the UCL Software Database. When outside UCL, first login to the vpn, and then procedd as normal.

  1. You may find it useful to add a remote machine to your ssh config file. This makes life a lot easier when transferring the files and interfacing with a remote machine. An example of how to do this is given in the example “Adding a remote machine”
  2. The remote_interface script will copy the parameter list to the remote machine, update a predefined COMSOL script with the new parameters, remotely run COMSOL, and retrieve the data back to your computer.
  3. With the data now retrieved, you can post-process the data to determine certain figures of merit. See the post-processing examples.