[DFTB-Plus-User] Correct Way to Run MPI-enabled DFTB+ (Conda Installation)

[Ankur Gupta]

Hi all,

I have installed the DFTB+ (MPI version) program through Anaconda. The
program seems to be working fine on a single processor. For example, for a
periodic structure containing 64 atoms, the DFTB+ program completed around
130 optimization steps at GFN2-xTB theory on a single processor (MPI
processes: 1, OpenMP threads: 1).

However, when I use multiple processors using the command "mpirun -np 12
dftb+ > DFTB_output'' (MPI processes: 12, OpenMP threads: 1), the
calculation becomes extremely slow. For the same molecule, it takes around
half an hour for one optimization step. I also set up the following
environment variables,
export OMP_NUM_THREADS=1
export OMP_PLACES=threads
export OMP_PROC_BIND=spread

Another thing I noticed is that if I don't set up these environment
variables, I get the following error,
libgomp: Thread creation failed: Resource temporarily unavailable

Therefore, I would like to know the correct way to run DFTB+ with MPI so
that I could make the computations faster.

Best,
Ankur

Best,
Ankur
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