Learning Forum

[edith.hartmann]

Hello, 

I am trying to run simulations on linux (ubuntu 20.04.6 LTS), but I have issues when launching the GUI interface of Lumerical. Below is the error message I get after trying to open a simulation file with the GUI:

e_hartmann@speckle:~$ ./tools/v242/bin/fdtd-solutions
Messages file /ansys_inc/shared_files/licensing/language/en-us/ansysli_msgs.xml does not exist.
./tools/v242/bin/fdtd-solutions: line 8: 1980362 Segmentation fault (core dumped) $FDTD_BIN_DIR/fdtd-solutions-app "$@" 

 

I also tried to open and launch a simulation using the terminal only: ./tools/v242/bin/fdtd-solutions -nw -run simulations/FDTD_run.lsf simulations/nanofin_test_FDTD_2.fsp

By doing that I don't get any error message but the simulation doesn't seem to run (no log file created).

Thank you for your help!

Edith Hartmann

[Lito]

Hi Edith, 

We have the following:

(1) Messages file /ansys_inc/shared_files/licensing/language/en-us/ansysli_msgs.xml does not exist.

You can ignore this message – this will not prevent opening or running the application. To remove this notice, create a blank XML (ansysli_msgs.xml) file in the said folder. 

(2) ./tools/v242/bin/fdtd-solutions: line 8: 1980362 Segmentation fault (core dumped) $FDTD_BIN_DIR/fdtd-solutions-app "$@"

This segmentation fault / core dump error is typically due to missing or incompatible system/graphics/OpenGL libraries. Make sure that you are connecting to the Ubuntu machine via a GUI connection e.g. VNC, X11forwarding and the Ubuntu machine has a /Desktop environment, e.g. Gnome or Mate. We have the following KB for more information. 

• Ubuntu Linux installation guide – Ansys Optics (option to downgrade cpio) 
• Required libraries for Ansys Lumerical on Linux – Ansys Optics 
• How to resolve system and OpenGL graphics related issues – Ansys Optics 

(3) ./tools/v242/bin/fdtd-solutions -nw -run simulations/FDTD_run.lsf simulations/nanofin_test_FDTD_2.fsp

The above command runs the FDTD_run.lsf and opens/uses the nanofin_test_FDTD_2.fsp indicated in the command. If you do not have the required libraries and support for OpenGL 3.2 and higher, this will result in the same segmentation fault / core dump error. Its the same as running the Lumerical FDTD CAD/IDE.   

/tools/v242/bin/fdtd-solutions &

Run FDTD simulation files directly from the command prompt using the engine/solver executable/binary not the CAD/IDE. This process does not require a GUI connection to the Linux machine (headless systems). Starting with 2024 R1, we do not bundle any MPI in Linux. See the KB and examples below for more information: 

• Running simulations using terminal on Linux – Ansys Optics  
• Running simulations with MPI on Linux – Ansys Optics 

## example below runs the simulation.fsp file without MPI using 32 threads/logical processer on the local machine
/tools/v242/bin/fdtd-engine -t 32 /pathto/simulationfile.fsp 
## example running OpenMPI with 32 processes, 1 process on 1 thread/logical processor  on the local machine
/pathto/openmpi/bin/mpiexec -n 32 /tools/v242/bin/fdtd-engine-ompi-lcl -t 1 -logall /pathto/simulationfile.fsp

Let me know if you have any questions or concerns. 

[edith.hartmann]

Hi Lito, 

Thank your for your response, it was very usefull!

Is there a way to run a parameter sweep or a script directly from the command prompt, without requiring a GUI connection ? I was only able to run a simple simulation file .fsp with the "fdtd-engine" command but I would be interested by running parameter sweeps.

Thank you for your help!

Edith Hartmann

[Lito]

@edith.hartmann,

You are welcome. 

(1) Please see the KB >> Running parameter sweeps without the CAD – Ansys Optics 

• Where save the parameter sweeps and run them outside the GUI using the “fdtd-engine” directly from the terminal. 

(2) You can either run them sequentially or concurrently – see KB below for more information. 

• Run FDTD simulations sequentially on the command prompt – Ansys Optics 
• Run simulations in parallel on local or remote machines – Ansys Optics 
• Standard license sharing for FDTD simulations on the command prompt – Ansys Optics

Let us know if you have any questions or other concerns.