Running FDTD simulations from the design environment

Check simulation memory requirements

The simulation and memory requirements utility provide an overview of the size and key properties of your simulation. It breaks down the amount of system memory (RAM) required to run a given simulation, the system memory required to collect all results from different MPI ranks, and the amount of disk space needed to save the results.

Notes 

• The memory estimate should only be considered while running a simulation on CPU. The memory report generated for a GPU simulation may greatly underestimate the requirements at the current stage. The user will be prompted by a warning message while checking the memory report when the simulation is set to be run on GPU.
• Check GPU simulation and memory requirements, also checks if the simulation has "express mode" enabled. It will not check if the machine has the hardware required to run on GPU. See this KB,  FDTD on GPU, for more information. 

CPU check memory requirements

GPU check memory requirements

Simulation passed (express mode is enabled) and can run on GPU.
Warning: memory estimates are for running on CPU.

Error: Simulation does not met requirements to run on GPU.
Enable 'express mode' in the simulation's advanced options.

Automatic memory check feature in FDTD 

• When running your simulation job from the Finite Difference IDE (CAD/GUI) on your local computer, by default FDTD will check your simulation to verify if you have enough system memory to run the job. If there is not enough memory you will be prompted with a warning: "Warning: Insufficient Memory" and "There is not enough system memory to run the simulation". From here you can choose to try and run the simulation anyways, or to abort the run.
• You can disable the automatic memory check either through the warning window or by opening "Check memory requirements", and unchecking "Auto check simulation memory".

Resolving insufficient memory issue

1. Run the simulation job on a machine with a sufficient amount of RAM. 
2. Run distributed computing using multiple machines/nodes in your network/cluster
   (note: MPI Rank 0 will need enough memory to collect the results from all the other nodes/ranks).

Simulation checkpoint 

1. Enable the simulation checkpoint feature in the "Advanced Options" of the FDTD Solver object. 
2. You can use the script commands, pause, resume, or resumejobs to stop/pause and resume your simulation job. 

Note: The option of resuming the simulation job when running from Terminal in Linux is available. Please refer to this KB guide for more information. 

Running simulation with MPI on Linux

• See this KB guide for more information. 

See also

Compute resource configuration use cases 

Resource configuration elements and controls 

RCWA Resource Configuration 

Resource configuration for Lumerical solvers running with a single process