[kgryte]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates the test suite for stats/base/dists/frechet/logcdf from relative tolerance (EPS/delta/tol) assertions to ULP difference assertions using @stdlib/assert/is-almost-same-value.
• updates test/test.logcdf.js, test/test.factory.js, and test/test.native.js. No other files are changed.

The ULP bound was tightened agentically: starting from a high bound and lowering to the minimum integer which still passes over the full fixture set (large_shape, large_scale, both_large; 1000 cases each, 3000 total per file).

Measured minimum ULP bounds:

File	Fixture	ULP
test/test.logcdf.js	large_shape	24
test/test.logcdf.js	large_scale	2
test/test.logcdf.js	both_large	20
test/test.factory.js	large_shape	24
test/test.factory.js	large_scale	2
test/test.factory.js	both_large	20
test/test.native.js	large_shape	24
test/test.native.js	large_scale	2
test/test.native.js	both_large	20

Each bound is the exact maximum observed ULP difference over its fixture: lowering 24 to 23 fails one assertion, 20 to 19 fails one assertion, and 2 to 1 fails twenty-nine assertions. The JavaScript and C implementations returned bit-identical results for every fixture value, so the same bounds apply in test/test.native.js as in the JavaScript tests.

For reference, the previous relative tolerances were 20.0 * EPS (large_shape, both_large) and 10.0 * EPS (large_scale), which correspond to looser accuracy budgets than the ULP bounds above, so this is a tightening rather than a relaxation.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

• Verification: test/test.js (3 assertions), test/test.logcdf.js (3025 assertions), test/test.factory.js (3022 assertions), and test/test.native.js (3025 assertions) all pass. The native add-on was built locally so that test/test.native.js was actually exercised rather than skipped.
• The full suite was run twice at the final bounds to confirm determinism (no FMA/architecture-dependent variation).
• ESLint (tests configuration, etc/eslint/.eslintrc.tests.js) is clean for all changed files.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

AI Assistance

When authoring the changes proposed in this PR, did you use any kind of AI assistance?

• Yes
• No

If you answered "yes" above, how did you use AI assistance?

• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
• Documentation (including examples)
• Research and understanding

Disclosure

If you answered "yes" to using AI assistance, please provide a short disclosure indicating how you used AI assistance. This helps reviewers determine how much scrutiny to apply when reviewing your contribution.

This PR was authored by Claude Code as part of an automated, mechanical migration of existing test assertions to ULP-based assertions, following the idiom established in previously merged PRs referencing #11352. The ULP bounds were determined empirically by running the fixtures and minimizing the accepted bound.

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@stdlib-js/reviewers

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/frechet/logcdf	$\\color{green}324/324$ $\\color{green}+100.00\\%$	$\\color{green}27/27$ $\\color{green}+100.00\\%$	$\\color{green}4/4$ $\\color{green}+100.00\\%$	$\\color{green}324/324$ $\\color{green}+100.00\\%$

The above coverage report was generated for the changes in this PR.