  Perturbative treatments of the lattice dynamics are widely successful for
many crystalline materials, their applicability is, however, limited for
strongly anharmonic systems, metastable crystal structures and liquids. The
full dynamics of these systems can, however, be accessed via molecular dynamics
(MD) simulations using correlation functions, which includes dynamical
structure factors providing a direct bridge to experiment. To simplify the
analysis of correlation functions, here the dynasor package is presented as a
flexible and efficient tool that enables the calculation of static and
dynamical structure factors, current correlation functions as well as their
partial counterparts from MD trajectories. The dynasor code can handle input
from several major open source MD packages and thanks to its C/Python structure
can be readily extended to support additional codes. The utility of dynasor is
demonstrated via examples for both solid and liquid single and multi-component
systems. In particular, the possibility to extract the full temperature
dependence of phonon frequencies and lifetimes is emphasized.
