Running OpenFAST simulations in parallel using WEIS executes on the same input #414
Description
I am currently using the WEIS framework for wind turbine optimization. During my recent runs using OpenFAST and ROSCO inside a WEIS optimization loop, I encountered the following fatal error, which causes the simulations to be terminated:
Fortran runtime error: File already opened in another unit
...
= EXIT CODE: 9
= YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Killed (signal 9)
The full log excerpt is as follows (only relevant part shown):
Running ElastoDyn.
Nodal outputs section of ElastoDyn input file not found or improperly formatted.
...
Warning: Turning off Unsteady Aerodynamics because polar has constant data.
...
Running ROSCO-v2.9.0
...
ROSCO Warning: Did not find correct size F_NotchFreqs in input file. Using default value...
...
Fortran runtime error: File already opened in another unit
...
= EXIT CODE: 9
= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
It appears that the crash is related to ROSCO's file handling in a parallel simulation context. I am using WEIS to run a design optimization where multiple design points are evaluated, and OpenFAST is invoked in parallel. I suspect the issue may be caused by file I/O conflicts when multiple OpenFAST instances are trying to access or write to the same control or output files.
My questions:
Could you please help confirm whether this error is caused by ROSCO’s Fortran file units being accessed simultaneously from multiple processes?
What is the recommended way to run WEIS with parallel OpenFAST evaluations using ROSCO safely?
Are there specific changes I should make to DISCON.IN files or ROSCO logging parameters to avoid such file conflicts?
Could this crash also be triggered by memory exhaustion (SIGKILL), or is it purely related to Fortran I/O?
Any guidance or recommendations for resolving this would be greatly appreciated.
Thank you very much for your time and support.
Best regards,