PIGLE (Particles Interacting in Generalized Langevin Equation simulator) is a fast simulator for the dynamics of multi species interacting particles responding to a 4D potential energy surface (3 spatial dimensions and one dimension for rigid body rotations), obeying the generalized Langevin Equation,

$$m\ddot{\mathbf{x}}_i = -\nabla V[\mathbf{x}_i(t)] – m\int_{-\infty}^t \gamma_i(t – t^\prime)\dot{\mathbf{x}}_i(t^\prime) \mathrm{d}t^\prime + \zeta(t) + \sum_{j\neq i}F_{ij},$$

which represents the classical thermal motion of particles.

PIGLE was written by N Avidor et al. and an up to date version of the code is maintained by the Cambridge Atom Scattering Facility. See the following resources for PIGLE

- The publication introducing PIGLE
- The permanent record of the code is kept at Zenodo
- Up to date code (currently the “sam” branch is recommended) is kept on the Atom Scattering Centre github page
- A getting started with PIGLE guide is available (currently incomplete)

Note that PIGLE is written in Matlab+Simulink so a license for both will be needed to run PIGLE.

### Additional support

The package provide means to compute statistics on the simulated trajectories – in the form of computing the Intermediate Scattering Function (both coherent and Incoherent). Furthermore, the package provides the means to expand the trajectories of the simulated point particles, to trajectories of configuration of scattering centers – allowing to calculate the ISF of a more realistic representation of the particle. Visualization means are provided as well.

If you want support using PIGLE contact the facility development scientist in the first instance (atomscattering@phy.cam.ac.uk).

### Acknowledgements

The development of the package was financially supported by the Blavatnik Foundation and the Herchel Smith fund.