Skip to content

THIRD_PARTY.md

Latest commit

 

History

History
83 lines (60 loc) · 3.61 KB

THIRD_PARTY.md

File metadata and controls

83 lines (60 loc) · 3.61 KB
Raw

Third-party code in PSI

The root LICENSE (MIT) covers PSI's own source. It does not cover the components below, which are redistributed under their own terms. This file exists so a license scan, or a user shipping a product built on PSI, can see what is here and what it requires.

Required notice

include/psi/dependence/space_filling_curve/hilbert.hpp is copyrighted by Rice University. Its terms require the following to be displayed anywhere the end-user would see PSI's own copyright:

Hilbert Curve implementation copyright 1998, Rice University

The same terms ask that modifications carry the name of the person who made them, the date, and the reason. Recorded here rather than in the file, so its notice stays verbatim:

  • made inline, so two translation units can both include it and still link;
  • wrapped in namespace psi::hilbert;
  • renamed from hilbert.c to hilbert.hpp on 2026-08-17. It was never C -- the namespace and the inline see to that -- and clang-format 20 began inferring Language: C from the extension and rewriting the whole file. Its own header still names it hilbert.c, which is the upstream file.

Git submodules

Not distributed in this repository — fetched by git submodule update --init.

Path Upstream Pinned License
include/parlaylib https://github.com/cmuparlay/parlaylib 36459f4 (master) MIT
include/libmorton https://github.com/Forceflow/libmorton 7923faa (v0.2.12) MIT

Vendored copies

These ship in the repository.

include/psi/dependence/cpam/ — a permanent fork of CPAM

Derived from CPAM (https://github.com/cmuparlay/CPAM, MIT), which builds on PAM (https://github.com/cmuparlay/PAM, MIT). This is a fork, not a mirror.

Measured against the pristine copy under include/baselines/cpam_raw (whitespace-insensitive, at commit da195e9 so PSI's later renaming is excluded): it diverges by roughly 2,842 lines across the shared files, with augmented_ops.h rewritten in 481 of 562 lines, map_ops.h in 882 and map.h in 460. It also adds cpam_sample_sort.h, which applies the space-filling curve. Those changes are PSI's own work and carry PSI's copyright.

Upstream CPAM/PAM is no longer maintained, so this fork is permanent. Do not plan to re-sync it, and do not read the divergence as drift to be reconciled.

The exact upstream commit these files were taken from is not recorded anywhere in the tree and could not be recovered; if you know it, add it here.

include/baselines/cpam_raw/ — CPAM and PAM, kept pristine

A second, unmodified copy of the same upstream projects (MIT), retained as the benchmark baseline that PSI is measured against. Only two files were touched, and only so they keep compiling against PSI's renamed types: cpamtree.hpp and cpam/augmented_ops.h.

Note for anyone comparing the two copies: PSI's fork reads a node's augmented bounding box by const & in the knn descent (augmented_node.h, used from augmented_ops.h) where this pristine copy returns it by value. That difference sits on the path the SPaC-vs-CPAM figures measure. It predates the 2026 refactor and is left as-is; it is recorded here so it is not mistaken for an accident.

include/baselines/zdtree/, include/baselines/zdtree_3d/

Implementations of a competing design, used only for benchmarking. They derive from PSI's own base_tree, and no upstream source or third-party copyright notice was found in them. If any of this code came from elsewhere, it should be attributed here.

Scope note

Everything under include/baselines/ exists to compare against and is not maintained as part of the library.