Method for calculating the global structure of (singular) spacetimes

A formalism and its numerical implementation is presented which allows one to calculate quantities determining the spacetime structure in the large directly. This. is achieved by conformal techniques by which null infinity (I+) and future timelike infinity (i(+)) are mapped to grid points on the numerical grid. The determination of the causal structure of singularities, the localization of event horizons, the extraction of radiation, and the avoidance of unphysical reflections at the outer boundary of the grid, are demonstrated with calculations of spherically symmetric models with a scalar field as matter and radiation model.