Running GPU simulations

Ansys Lumerical FDTD™ supports running FDTD simulations on GPU. After you complete configuration of GPU resources, you can follow the instructions in this article to run simulations.

Information on this page pertains to running simulations on local or remote resources you have set up yourself. For running simulations on Ansys Cloud Burst Compute™, which gives you access to the latest high-performance GPU hardware on the cloud and requires no IT or HPC experience, see the Ansys Cloud Burst Compute™ for Lumerical Knowledge Base article.

Single simulations

Running in the GUI

Prior to running simulations, click the GPU button in the Check group of the FDTD tab to ensure that your simulation meets memory requirements and that no unsupported simulation objects are present.

To run FDTD simulations using GPU, select the GPU toggle in the “Run Simulation” group under the “FDTD” tab. Then, select the desired GPU using the dropdown menu, and press run to run a single simulation on GPU. For more information on the dropdown selection, see the Knowledge Base article on the modern user interface.

Script access

You can also check and run the simulation with script.

To check the simulation, use the runsystemcheck command.

sim_req = runsystemcheck("FDTD","GPU") #Return a structure with simulation and memory requirements for GPU simulation of the current file

To run the simulation, you can use the setdevice and run commands.

setdevice("GPU");
run; #Run with the first active GPU resource

run("FDTD","GPU","Local Host"); #Run with a specific GPU resource

Sweeps and Optimizations

Running in the GUI

The type of resource to be used for a sweep or an optimization is controlled by a CPU/GPU drop-down list near the run button in the Optimization and Sweeps toolbar.

To enable the drop-down list, the selected sweep must have the solver type “FDTD”, which is available in the property window of the sweep entry.

For optimizations and Monte Carlo analysis, you can only change this option if the FDTD solver is the first enabled solver in the Object Tree.

Pressing run , with GPU selected in the drop-down list, runs the selected sweep on enabled GPU resources. You can also access in this in the context menu for each sweep.

Script access

You can run GPU sweep using a mode flag in the runsweep command, as shown below.

runsweep; #< run all sweeps in CPU mode
runsweep(“CPU”) #< run all sweeps in CPU mode
runsweep(“GPU”) #< run all sweeps in GPU mode, if there is a sweep incompatible with GPU computing (i.e., non FDTD solver), this will result in error
runsweep(“thickness sweep”, “GPU”) #< run sweep with name of “thickness sweep” using GPU

Note: When accessing sweeps using script, do not use sweep names “CPU” and “GPU”. These names are ambiguous and will therefore result in errors for the runsweep command.

See Also

Getting started with running FDTD on GPU, Resource configuration for single node GPU simulations