EBWeyl: A code to invariantly characterize numerical spacetimes

Abstract Relativistic cosmology can be formulated covariantly, but in dealing with numerical relativity simulations a gauge choice is necessary. Although observables should gauge-invariant, do not necessarily focus on their computations, while it useful to extract results invariantly. To this end, order invariantly characterize spacetimes resulting from cosmological simulations, we present two different methodologies compute the electric and magnetic parts of Weyl tensor, E α β $B_{\alpha\beta}$?> B , which construct scalar invariants scalars. The first method geometrical, computing these tensors full metric, second uses 3 + 1 slicing formulation. We developed code for each tested them five analytic metrics, derived various scalars constructed computer algebra software. find excellent agreement between results. outperforms geometrical computational convenience accuracy; basis make publicly available github name EBWeyl. emphasize that post-processing applicable any spacetime gauge.