Unrecognized Dihedral Style 'fourier' in LAMMPS Versions 22Dec2022 and 2Aug2023

Hello LAMMPS Developers and Community,

I encountered an issue with the most recent versions of LAMMPS (22Dec2022 and 2Aug2023). When I tried to use the dihedral style ‘fourier’, I received the following error message:

ERROR: Unrecognized dihedral style ‘fourier’ (…/force.cpp:510)
Last command: dihedral_style fourier

For reference, here is the snippet of my input file where I define the dihedral style:

dihedral_style fourier
dihedral_coeff 1 1 0.1084102605964990 2 180.00 ##Gdm
dihedral_coeff 2 1 0.0433641042385997 2 180.00
dihedral_coeff 3 2 0.108410260596499 2 180.00 0.0867282084771994 2 0.0 ##Urea
dihedral_coeff 4 1 0.108410260596499 2 180.00
dihedral_coeff 5 1 0.455323094505297 2 180.00
dihedral_coeff 6 1 0.0433641042385997 2 180.00

I checked the LAMMPS documentation and ensured that I followed the correct syntax, but I still encountered the issue. Is there a possible bug with the recognition of the ‘fourier’ dihedral style in these versions of LAMMPS?

I would appreciate any guidance or suggestions to resolve this issue. Thank you for your continued support and development of LAMMPS.

Hi @musong_mm,

The dihedral style fourier is part of the EXTRA-MOLECULE package which needs to be included during LAMMPS compilation. You can check if this package is part of your executable by passing the -h command line argument.

If not you should either see with whoever compiled your LAMMPS executable, or follow the include package instructions of the manual before compiling.

Thank you for pointing out the error! I ignored the issue of package installation. Now the program works perfectly!

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