The parameters file allows the user to set the parameters of the finite-difference time-domain simulation.
Creating the parameters file
The parameters file can be created using any text editor, and can be named by any name. In the FDTD wiki, this file will be assumed to have the name
param. This file should be placed in the work directory.
Flags are true/false values that control an aspect of the simulation. By default, all flags are false. In order to invoke a flag, a simple line is written to the parameters file as follows:
flag is the name of the parameter, which sets the flag to true.
An example of a flag is xperiodic, which turns on periodicity along the $x$-direction. In this case, the following would be added to the parameters file:
Settings set the value of a given parameter. In order to set a setting, the following line is written to the parameters file:
setting is the setting that you wish to set, and
value is the corresponding value. Note that in the FDTD wiki,
value will often be replaced with
str, depending on whether a number or string is expected, respectively.
As an example, to change the grid size in all directions ($x$, $y$, and $z$) to 0.5 nm, the following would be added to the parameters file:
dx 0.5e-9 dy 0.5e-9 dz 0.5e-9
Example parameters files can be found accompanying the tutorials section.