SpECTRE

SpECTRE: Discontinuous Galerkin Numerical Relativity

Added to the survey on 2026-10-06 by the Research Toolkit's research pass. The scores below are that pass's assessment from the evidence cited under References, on the survey's four axes and scale; they are not the original survey's (2026-09-26), and no rule of the Principia Machina reads them. See the additions on the front page.

Overview & Architectural Fit

SpECTRE evolves the equations of relativistic astrophysics (mergers of black holes and neutron stars, supernovae) with a task-based discontinuous Galerkin and spectral-element method, written in C++ on Charm++. It solves systems in the conservation form ${\partial }_{t}u+{\partial }_i{F}^i(u)=S(u)$ to high order on many processors.

Mathematical Evaluation for TPM

• Lagrangian / Action (1.5/10): Evolves fixed formulations and takes no action as input.
• Field / PDE (8.5/10): High-order and massively parallel.
• Relativity (9/10): A strong-field relativity code.
• Quantum / Data (1.5/10): Little quantum or data focus.

Integration Pipeline

1. Reduce the container's action-derived gravity to general relativity in the limit of interest.
2. Take SpECTRE's (and the Einstein Toolkit's) solutions and waveforms as the trusted benchmark for that limit, compared only after the derivation (quarantine).
3. For a new theory, a well-posed hyperbolic formulation must exist first, then be implemented in C++.

Status, Licence and Limits

• Status: Very active, releases about monthly; the latest, v2026.09.05 of 6 September 2026, has a Zenodo DOI.
• Licence: MIT.
• Home: https://spectre-code.org
• Limits: The Charm++ build and its high-performance computing needs are heavy. It consumes action-derived equations; it never produces them.

On the Principia Machina

A tool runs only where the sponsor installed and bound it, and what it returns is untrusted input, vetted before use; its numbers are never values of the site's calculator, TPC. A value it computes lands as a RESULT with QUANTITY, VALUE, UNIT and AT, its initial and boundary values as SITUATION records; the regime of a numerical result, and whether such a value may be presented, are open questions of the specification. See Agent/Tools and the operator's guide.

References

• SPECTRE2017 – Kidder L.E., Field S.E., Foucart F., Schnetter E., Teukolsky S.A., Bohn A., Deppe N., Diener P., Hébert F., Lippuner J., Miller J., Ott C.D., Scheel M.A., Vincent T. (2017). SpECTRE: A task-based discontinuous Galerkin code for relativistic astrophysics. J. Comput. Phys. 335, 84–114. doi:10.1016/j.jcp.2016.12.059.
• SPECTRE-SITE – SXS Collaboration / SpECTRE developers (2026). SpECTRE v2026.09.05. Zenodo. doi:10.5281/zenodo.22433001.