Chapter 11 prep

[henrydingliu]

Summary of Changes

Related GitHub Issue(s)

Additional Context for Reviewers

• I passed tests locally for both code (uv run pytest) and documentation changes (uv run jb build docs --builder=custom --custom-builder=doctest)

---

Note

Medium Risk
Changes to nan_triangle (dropping the is_pattern shortcut) and full-triangle TriangleWeight logic can alter development/LDF and weighted fits; refreshed sample CSVs will change any test or doc that depended on the old rounded values.

Overview
Prepares Friedland textbook workflows (including upcoming Chapter 11) by refreshing bundled sample data and tightening triangle/weighting behavior.

Sample data and manifest: Friedland CSVs are updated with finer paid/reported amounts and new columns (e.g. Reported Claims on friedland_gl_insurer). The standalone friedland_xyz_disp dataset is removed from the manifest and deleted; disposal-style figures remain available via friedland_xyz_auto_bi. Friedland chapters 6–7 doctest outputs are adjusted to match the new numbers.

Triangle core: nan_triangle no longer treats pattern triangles as all-valid; only ultimate triangles still get a full mask. _drop_subtriangles also clears ndarray w_ weights so copies do not keep stale weight arrays.

TriangleWeight: n_periods weighting works on full triangles (e.g. full_triangle_) via X.is_full, using origin slicing instead of valuation filtering. Typing moves to TriangleProtocol; tests cover drop_valuation exhausting the triangle and parity between standard and full-triangle fits.

Weighted regression: Standard OLS uses explicit weighted means for slope/intercept and exposes rsq_ on the fitted model.

^{Reviewed by Cursor Bugbot for commit d22d88d. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Pyright Type Completeness

View the full pyright --verifytypes output for this commit

Project (full chainladder package, at this PR's head): 14.1% of exported symbols fully typed (175 / 1242)

	Known	Ambiguous	Unknown	Total
Project (head)	175	107	960	1242

Other symbols referenced but not exported by chainladder: 13

	Known	Ambiguous	Unknown	Total
Other (head)	3	1	9	13

Symbols without documentation:

• Functions without docstring: 314
• Functions without default param: 0
• Classes without docstring: 10

Patch (exported symbols added or changed by this PR): 0.0% fully typed (0 / 3)

	Known	Ambiguous	Unknown	Total
Patch	0	0	3	3

Patch symbol details

Symbol	Status	Change
chainladder.utils.tests.test_utilities.test_triangleweight_drop_valuation_all	❌ unknown	new
chainladder.utils.tests.test_utilities.test_triangleweight_full_triangle	❌ unknown	new
chainladder.utils.weighted_regression.WeightedRegression.rsq_	❌ unknown	new

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.62%. Comparing base (921bfca) to head (d22d88d).
⚠️ Report is 3 commits behind head on experimental.

Additional details and impacted files

@@               Coverage Diff                @@
##           experimental    #1078      +/-   ##
================================================
- Coverage         89.75%   89.62%   -0.14%     
================================================
  Files                91       91              
  Lines              5408     5299     -109     
  Branches            696      673      -23     
================================================
- Hits               4854     4749     -105     
+ Misses              389      386       -3     
+ Partials            165      164       -1     

Flag	Coverage Δ
unittests	89.62% <100.00%> (-0.14%)	⬇️

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