As mentioned earlier, ULaMDyn provides three classes of symmetry-aware descriptors (translational and rotational invariant) based on molecular geometries: the pairwise atom -atom distances (R2 family of descriptors) and the Z-Matrix representation. These descriptors are computed by processing the NAMD molecular geometries stored in the GetCoords() object. In the example provided below (Figure ), the function build_descriptor() within the R2 descriptor class is used to return a Pandas data frame object with the descriptor calculated for all geometries of each NAMD trajectory. Additional flexibility for representing molecular structures in a manner invariant to translational and rotational transformations is offered by other variants of the R2 descriptor supported by this function.