People skip from "I have a GPU partition" to "I built the full application" and then spend a day debugging a solver that never saw a device.
Get an allocation that includes a GPU#
If this fails, stop. Compiling will not fix the scheduler.
Run a kernel that is not your code#
A 20-line vector add, built with the site CUDA/HIP module, launched with
srun. Confirm the device name matches the partition you requested.Then load the application#
Now
module load gromacs-gpu (or whatever you actually wanted). Check that the binary is the GPU build. Run one timestep. Watch nvidia-smi in a second SSH inside the allocation if the site allows srun --overlap, or dump utilisation at the end of the job.Only then scale#
Multi-GPU and multi-node GPU-aware MPI are where site stacks differ. They are not the first experiment.