search

ExpHP / rsp2

phonons in rust
Apache License 2.0
2 stars 1 forks source link

MoS2/react giving 'Multiple shortest images found for a vector' #121

Open ExpHP opened 3 years ago

ExpHP commented 3 years ago 
Multiple shortest images found for a vector in the force constants! This could mean that your supercell is not large enough
Lattice: Lattice { matrix: [[37.74281158030467, 0.0, 0.0], [-18.871405790152334, 32.68623363879334, 0.0], [0.0, 0.0, 16.150331148353676]], inverse: [[0.026495111469698508, 0.0, 0.0], [0.015296959739239575, 0.03059391947847915, 0.0], [0.0, 0.0, 0.06191823503891048]] }
                 | Vectors: [[9.435702895076169, -16.34311681939667, -6.150331148353676], [-9.435702895076165, 16.34311681939667, -6.150331148353676]]
                 | Force: [[0.1463739778609533, 0.1623450387351549, 0.002471237898721504], [0.16234503873515482, -0.04108592576973051, 0.00142676986605846], [0.0005489544799001378, 0.00031693901674321567, 0.04909904604951542]

Probably due to nondeterministic forces (might need to set a cutoff) but not sure yet

ExpHP commented 3 years ago

Brandon's FORCE_SETS

https://gist.github.com/ExpHP/fbb28fd8c38e94a9a1f0c6af117d6429

Largest values are around 1e-1, not very large compared to most values around 1e-5. These don't look like rounding error.