SHEET-AD: A Fixed-Graph Symplectic and Differentiable Phase-Sheet Discretization for the Cosmological Vlasov–Poisson System

This archive provides the reproducibility package associated with the manuscript “SHEET-AD: A Fixed-Graph Symplectic and Differentiable Phase-Sheet Discretization for the Cosmological Vlasov–Poisson System.” SHEET-AD is a computational framework for the cold cosmological Vlasov–Poisson system. The method combines a high-order Lagrangian phase-sheet representation, conservative partition-of-unity sheet-to-grid mass projection, an energy-consistent variational gravitational force, fixed-graph symplectic kick–drift–kick time integration, caustic-aware adaptive indicators, recorded remeshing transfers, and fixed-graph reverse-mode adjoints of the accepted discrete operators. The archive contains the scripts, numerical data, figure-generation workflow, diagnostic checks, dependency files, container recipes, random-seed manifest, tolerance configuration, and checksum records needed to reproduce the computational evidence reported in the manuscript. It includes validation of conservative projection, Poisson sign and residual conventions, high-order remeshing-transfer adjoints, folded-sheet projection, compact adaptive three-dimensional particle-mesh comparisons, metric-sensitivity studies, fixed-graph adjoint tests, and figure generation. The archive intentionally excludes LaTeX manuscript source files. It includes the compiled manuscript PDF only for reference. The workflow is designed around a deterministic reference implementation and can be executed using the included Makefile, dependency lock files, and container recipes.