Example 01_Methane Dreiding Forcefield

[GustavoG9]

For some reason whenever I try to run the first example it throws the following error: PysimmError: A pair_style must be defined during initialization

from pysimm import system, lmps, forcefield

s = system.System()

m = s.molecules.add(system.Molecule())

f = forcefield.Dreiding()
#f = forcefield.Gaff2()

dreiding_C_ = s.particle_types.add(f.particle_types.get('C_3')[0].copy())
dreiding_H_ = s.particle_types.add(f.particle_types.get('H_')[0].copy())

#gaff_c3 = s.particle_types.add(f.particle_types.get('c3')[0].copy())
#gaff_hc = s.particle_types.add(f.particle_types.get('hc')[0].copy())

#c1 = s.particles.add(system.Particle(type=gaff_c3, x=0, y=0, z=0, charge=0, molecule=m))
c1 = s.particles.add(system.Particle(type=dreiding_C_, x=0, y=0, z=0, charge=0, molecule=m))

#h1 = s.add_particle_bonded_to(system.Particle(type=gaff_hc, charge=0, molecule=m), c1, f)
#h2 = s.add_particle_bonded_to(system.Particle(type=gaff_hc, charge=0, molecule=m), c1, f)
#h3 = s.add_particle_bonded_to(system.Particle(type=gaff_hc, charge=0, molecule=m), c1, f)
#h4 = s.add_particle_bonded_to(system.Particle(type=gaff_hc, charge=0, molecule=m), c1, f)

h1 = s.add_particle_bonded_to(system.Particle(type=dreiding_H_, charge=0, molecule=m), c1, f)
h2 = s.add_particle_bonded_to(system.Particle(type=dreiding_H_, charge=0, molecule=m), c1, f)
h3 = s.add_particle_bonded_to(system.Particle(type=dreiding_H_, charge=0, molecule=m), c1, f)
h4 = s.add_particle_bonded_to(system.Particle(type=dreiding_H_, charge=0, molecule=m), c1, f)

s.apply_charges(f, charges='gasteiger')

s.set_box(padding=10)

s.bond_style='lj'
s.pair_style='harmonic'
s.angle_style='harmonic'

lmps.quick_min(s, min_style='fire', name='fire_min')

#lmps.quick_min(s, min_style='sd', name='min_sd')
#lmps.quick_min(s, min_style='cg', name='min_cg')

s.write_pdb('methane.pdb')

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Do you have any idea what could be wrong?
Thanks in advance!

[saabirpetker]

Line 15 s.forcefield=f.name in create.py is missing in the README