Cc: error: unrecognized command line option ‘-qopenmp’ while compiling dftd4-python with meson about dftd4

[ghifi37]

I found gcc works well by the definition: FC=ifort CC=icc CXX=icpc. Does it mean that gcc can not compile the project?

If I install dftd4-python in /home/gp/anaconda3, "from dftd4.ase import DFTD4" will cause:

Traceback (most recent call last):
File "/home/gp/anaconda3/lib/python3.7/site-packages/dftd4/libdftd4.py", line 32, in
from ._libdftd4 import ffi, lib
ImportError: /home/gp/anaconda3/lib/python3.7/site-packages/dftd4/libdftd4.cpython-37m-x86_64-linux-gnu.so: undefined symbol: iso_c_binding_mp_c_null_ptr

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "", line 1, in
File "/home/gp/anaconda3/lib/python3.7/site-packages/dftd4/ase.py", line 86, in
from .interface import DispersionModel, DampingParam
File "/home/gp/anaconda3/lib/python3.7/site-packages/dftd4/interface.py", line 22, in
from .libdftd4 import (
File "/home/gp/anaconda3/lib/python3.7/site-packages/dftd4/libdftd4.py", line 34, in
raise ImportError("dftd4 C extension unimportable, cannot use C-API")
ImportError: dftd4 C extension unimportable, cannot use C-API

If I install dftd4-python in other paths, "from dftd4.ase import DFTD4" will cause:

Traceback (most recent call last):
File "", line 1, in
ModuleNotFoundError: No module named 'dftd4'

Conda does not finish install because of the inconsistent libs, pip has compilation errors.
How could I install dftd4-python correctly?

[awvwgk]

meson setup _build -Dpython_version=3 -Dfortran_link_args=-qopenmp

The option -qopenmp is specific to Intel Fortran compilers, especially adding the option -Dfortran_link_args=-qopenmp to the configuration step is only required when building against the MKL with Intel 2021. Note that you must build against the MKL-RT library to build a Python extension module, therefore this option is not needed here.

ImportError: /home/gp/anaconda3/lib/python3.7/site-packages/dftd4/libdftd4.cpython-37m-x86_64-linux-gnu.so: undefined symbol: iso_c_binding_mp_c_null_ptr

It looks like you are mixing up an Intel compiled binary with a GCC compiled binary, the Fortran runtime will mismatch and therefore you can't find the required symbols. It is important to use the matching C compiler to compile the Python extension module you used for compiling the Fortran library.

[ghifi37]

Thank you, Sebastian. It should be because that my compiler configuration was confused as you wrote. I am trying to correct it.

[awvwgk]

The build system from DFT-D4 got several improvements since this issue was opened. Feel free to open a new issue if this is still relevant.