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This is the second in a series of two articles introducing the Gravitascomputational general relativity framework, in which we now focus upon thedesign and capabilities of Gravitas's numerical subsystem, including itsability to perform general 3+1 decompositions of spacetime via the ADMformalism, its support for the definition and construction of arbitrary Cauchysurfaces as initial data, its support for the definition and enforcement ofarbitrary gauge and coordinate conditions, its various algorithms for ensuringthe satisfaction of the ADM Hamiltonian and momentum constraints, and itsunique adaptive refinement algorithms based on hypergraph rewriting via Wolframmodel evolution. Particular attention is paid to the seamless integrationbetween Gravitas's symbolic and numerical subsystems, its ability to configure,run, analyze and visualize complex numerical relativity simulations and theiroutputs within a single notebook environment, and its capabilities for handlinggeneric curvilinear coordinate systems and spacetimes with general (and oftenhighly non-trivial) topologies using its specialized and highly efficienthypergraph-based numerical algorithms. We also provide illustrations ofGravitas's functionality for the visualization of hypergraph geometries andspacetime embedding diagrams, the ability for Gravitas's symbolic and numericalsubsystems to be used in concert for the extraction of gravitational wavesignals and other crucial simulation data, and Gravitas's in-built library ofstandard initial data, matter distributions and gauge conditions. We concludeby demonstrating how the numerical subsystem can be used to set up, run,visualize and analyze a standard yet nevertheless reasonably challengingnumerical relativity test case: a binary black hole collision and merger withina vacuum spacetime (including the extraction of its outgoing gravitational waveprofile).

Computational General Relativity in the Wolfram Language using Gravitas II: ADM Formalism and Numerical Relativity