test: migrate stats/base/dists/logistic/mgf to ULP-based assertions

[kgryte]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates the tests for stats/base/dists/logistic/mgf from relative tolerance testing to ULP difference testing.

Changes are limited to the package's test files:

• test/test.mgf.js
• test/test.factory.js
• test/test.native.js

In each fixture loop, the delta/tol computation and the y === expected[i] special case are replaced with a single assertion:

t.strictEqual( isAlmostSameValue( y, expected[ i ], 3 ), true, 'returns expected value' );

The @stdlib/assert/is-almost-same-value require is added, and the now unused @stdlib/math/base/special/abs and @stdlib/constants/float64/eps requires are removed. No fixtures, implementations, or test cases were otherwise modified.

ULP bound: 3, applied uniformly across all three test files.

This is the measured minimum. Maximum observed ULP difference over the full fixture set (3 fixtures x 1000 values, evaluated against both lib/main.js and lib/factory.js):

Fixture	max ULP (JS)	max ULP (C)
positive_mean.json	2	2
negative_mean.json	2	2
large_variance.json	3	3

Tightness was confirmed by re-running the suite at lower bounds: 2 fails (1 assertion), 1 fails (156), and 0 fails (621). The suite was run twice at 3 with identical results (3011 passing assertions in test.mgf.js, 3017 in test.factory.js, 0 failures), so the bound is not sensitive to run-to-run variation.

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.

The C implementation (src/main.c) mirrors the JS implementation exactly (exp( mu*t ) / sinc( s*t )). Because the Node addon was not built in the environment used to prepare this PR, test/test.native.js skipped locally. To avoid guessing at the native bound, the C routine was compiled into a standalone harness and evaluated against the same fixtures; it agrees with the JS implementation and also peaks at 3 ULP, which is why test.native.js uses the same constant.

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

This PR was authored by Claude Code running as an unattended scheduled task. The test migration, the ULP bound measurement, and this description were produced by Claude Code; the ULP bound was determined empirically by measuring the fixture set and verifying that lower bounds fail.

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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/logistic/mgf	$\\color{green}306/306$ $\\color{green}+100.00\\%$	$\\color{green}22/22$ $\\color{green}+100.00\\%$	$\\color{green}4/4$ $\\color{green}+100.00\\%$	$\\color{green}306/306$ $\\color{green}+100.00\\%$

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