Comments which code to choose for your calculation
- looper: models with inversion symmetry in spin space
- sse: models with anisotropy that breaks inversion symmetry in spin space, e.g. Heisenberg models in a magnetic field
Simple Heisenberg models can be simulated with either of these. Looper has the smaller range of applicability, but if applicable, it shows the best performance (shortest autocorrelation time).