maxwell

A 2D FDTD solver for Maxwell's equations

Features

Maxwell is a work in progress. Currently, it offers:

• GPU acceleration via OpenCL, with CPU fallback
• User-specified boundary conditions
  • Natural - No enforced BCs, just allow the effects of the discretization to act
  • PEC - Perfect electric conductor, roughly analogous to the simulation space being within a metal box
  • PML - Perfectly matched layers, roughly analgous to the simulation space being surrounded to infinity by free space
• User-defined sources coupled to arbitrary field components
  • Sinusoids with linear frequency as argument
• User-defined regions of arbitrary DC material properties (permittivity and permeability)
  • Triangle
  • Circle
• Live simulation rendering
• User-interactivity
• Multiple visualization functions

Usage

To use Maxwell, you must call it with a single argument:

./maxwell [sim_file]

Where sim_file is a user-created configuration file specifying a simulation to run. See Simulation Files for more details. While the simulation is running, there are a variety of options for user-interactivity:

• [Space] - Pause/resume the simulation
• [Ctrl]+[C] - Exit the program
• [B] - Toggle rendering of material boundaries
• [F] - Report current average framerate
• [R] - Reset the simulation to its initial state
• [V] - Cycle between visualization functions

Simulation Files

A simulation file consists of multiple sections: [Simulation], [Sources], and [Materials]. To begin a section, simply specify its complete name (including square brackets) on a line of its own. Options for the section follow on their own lines. Here are the currently available options:

[Simulation]
Width [Width]
Height [Height]
Boundary {Natural, PEC, PML [layers] [max_conductivity] [poly_order]}
ComputeOn {CPU, GPU}

[Sources]
SineLinFreq [FieldComponent] [x] [y] [LinearFrequency] [Phase]

[Materials]
Triangle [RelativePermittivity] [RelativePermeability] [Conductivity] [x1] [y1] [x2] [y2] [x3] [y3]
Circle [RelativePermittivity] [RelativePermeability] [Conductivity] [x] [y] [R]

For PML boundaries, [layers] is the number of additional grid-point layers to surround the main simulation space with. [max_conductivity] is the maximum conductivity value the PML region will reach, at the farthest point from the simulation region. [poly_order] is the order of the polynomial used to fit between the minimum conductivity of 0 at the border with the simulation region, and the maximum value.

For material properties, permittivities and permeabilities are multiplicative, while conductivities are additive.

See the examples folder for example simulation files.

Building

If you want to use GPU acceleration, you'll need OpenCL. Regardless, you will also need OpenGL and GLFW. Installation will depend on your distribution. Simply run make to compile the binary. For a fun demo:

./maxwell examples/phased_array_prisms.sim