feat: add C implementation for math/base/special/betainc

[Neerajpathak07]

Progresses #649
Resolves #3423

Description

What is the purpose of this pull request?

This pull request:

• adds C implementation for math/base/special/betainc

Related Issues

Does this pull request have any related issues?

This pull request:

• progresses [RFC]: Add C implementations to base special math functions (tracking issue) #649

• resolves [RFC]: Add C implementation for @stdlib/stats/base/dists/beta/cdf #3423

Questions

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No.

Other

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No.

Checklist

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

• Read, understood, and followed the contributing guidelines

---

@stdlib-js/reviewers

[Neerajpathak07]

This PR will need the C implementation for math/base/special/kernel-betainc to be merged to develop.

[Neerajpathak07]

Reference:-

[rautelaKamal]

Hey @Neerajpathak07, was reviewing this since it depends on kernel-betainc which I've been following closely. Found a few things in src/main.c that might block compilation:

Line 52 uses double out = [ 0.0, 0.0 ] which is JS syntax - in C this would need to be separate variable declarations like double out; double deriv;

Lines 53-54 redeclare regularized and upper, which are already function parameters - compiler will error there.

Line 55 calls stdlib_base_kernelBetainc but the actual C function in #10279 is stdlib_base_kernel_betainc (snake_case), and it expects pointer arguments (&out, &deriv) rather than array and stride.

The header include on line 27 should be kernel_betainc.h instead of kernelbetainc.h.

Also minor - the @returns JSDoc says "natural logarithm of beta function" but the function returns the incomplete beta value, worth updating to avoid confusion.

Hope this helps move things forward!

[github-actions]

⚠️ Issue Reference Review

An automated check found a potentially unrelated issue/PR reference in this PR:

Reference	Assessment	Reasoning
#3423	suspicious	PR adds math/base/special/betainc (the regularized incomplete beta function), but #3423 is an RFC specifically requesting a C implementation for the stats/base/dists/beta/cdf package (different directory, different RFC requirements). While betainc is the underlying mathematical implementation of the beta CDF, the RFC requires adding C source, native addon, tests, benchmarks, and examples to the stats/base/dists/beta/cdf package itself — which this PR does not appear to do.

Why this matters: GitHub automatically closes issues referenced with closing keywords (Resolves, Closes, Fixes) when the PR is merged. If Resolves #3423 is merged, the stats/base/dists/beta/cdf RFC would be automatically closed even though that package's C implementation hasn't been added yet.

What to do:

• If this PR truly resolves the stats/base/dists/beta/cdf RFC in full (i.e., it also adds C implementation, native addon, benchmarks, and examples to that package), then no action is needed.
• If this PR only adds math/base/special/betainc (a prerequisite/dependency of stats/base/dists/beta/cdf), consider changing Resolves #3423 to Progresses #3423 or Related to #3423 to avoid accidentally closing the RFC.

This assessment was generated by an AI model and is informational only.

Generated by Check PR Issue References · ◷

[Neerajpathak07]

@rautelaKamal why do we have multiple duplicate comments here correct me if I am mistaken here but are you using any LLM's to perform code reviews?

[Neerajpathak07]

Suggested change

	#include "stdlib/math/base/special/kernelbetainc.h"
	#include "stdlib/math/base/special/kernel_betainc.h"

Awaiting the necessary C implementation for the dependent package.