trendfollowing 1.0.4

Portfolio-level volatility targeting in the European system produced undefined
leverage on days of non-positive portfolio variance, and this release is the first
to carry the fix. np.reciprocal(..., where=portfolio_var > 0.0) was called
without out=, so the cells the mask skips were left holding whatever the freshly
allocated buffer contained rather than zero. run_european_tf_system with
portfolio_covar_span set could therefore apply arbitrary leverage on those days,
and the value was not reproducible between runs. The fix (4b6e39a, 2026-07-22)
allocates a zero array and passes it as out=, so a non-positive-variance day
gets zero leverage. Any European-system result produced with portfolio_covar_span
set on a version at or below 1.0.3 should be regenerated.

trendfollowing/systems/american.py and trendfollowing/systems/tsmom.py still
call np.reciprocal the same way. Those two lines are unchanged in this release
and are the open item behind it.

1.0.3 was published without a changelog entry; it was a version bump in
pyproject.toml and nothing else (ff28a8a).

Added

• tests/test_version_metadata.py: pyproject.toml, CITATION.cff and the
  @software BibTeX entry in README.md must carry the same version, and
  date-released must be an ISO date. The three had drifted — see below.
• A version-carrying @software BibTeX entry in README.md. The README cited the
  paper and nothing else, so a replication had no way to record which version of
  the code it ran; for a replication package that is the citation that matters.

Fixed

• CITATION.cff said 1.0.0 against a published 1.0.3, so anyone citing the package
  from that file named a release three patches behind the code that produced the
  paper's tables. It now says 1.0.4 with a current date-released, and the new test
  fails if it drifts again.

Changed

• numpy floor raised to >=2.0, matching the rest of the stack. No resolution
  changes: qis already requires it, so every install has resolved numpy 2.x
  regardless of what this file declared.
• ruff no longer selects I. Import order here groups the scientific stack before
  the project packages, which isort's ordering contradicts; the rule was selected in
  this repository and in no other of the stack.
• AGENTS.md records the top-level tests/ layout as a deliberate
  replication-package deviation rather than a drift from the in-package convention
  the siblings use.

Removed

• .coverage and example_ar1_knife_edge.png are no longer tracked. Both are
  generated: the PNG is written into the working directory by
  examples/analytic_sharpe_vs_span.py, and nothing in the README or the papers
  tree references it. .gitignore now covers .coverage* and example_*.png.