feat: add math/base/special/round10f

[aryan7071]

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Resolves none

Description

What is the purpose of this pull request?

This pull request:

• Adds the complete implementation for math/base/special/round10f.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

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

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No.

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Checklist

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• Read, understood, and followed the contributing guidelines.

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/round10f	$\\color{green}192/192$ $\\color{green}+0.00\\%$	$\\color{green}15/15$ $\\color{green}+0.00\\%$	$\\color{green}2/2$ $\\color{green}+0.00\\%$	$\\color{green}192/192$ $\\color{green}+0.00\\%$

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

[Planeshifter]

PR is mmissing binding.gyp, include.gypi, manifest.json, src/Makefile, and other required build configuration.

[aryan7071]

@Planeshifter Yes sir I was working on that but I stepped on some error, so I'm just fixing that.

[Planeshifter]

Still mismatch for parameters in

• lib/node_modules/@stdlib/math/base/special/round10f/lib/main.js
• lib/node_modules/@stdlib/math/base/special/round10f/docs/types/index.d.ts
• lib/node_modules/@stdlib/math/base/special/round10f/docs/types/test.ts
• lib/node_modules/@stdlib/math/base/special/round10f/docs/repl.txt

[anandkaranubc]

Will come back to the PR once @stdlib/math/base/special/log10 is merged via #8873

[kgryte]

@anandkaranubc This is now unblocked.

[anandkaranubc]

We (Claude & I) intentionally compute the powers of ten in double-precision and round the result to single-precision, rather than using powf directly.

The reason: powf( 10.0f, e ) does not always return the closest single-precision float to the exact power of ten. It is off by 1 ULP for e = -36, -22, -18, 11 (found by brute-force comparison against exact arbitrary-precision values).

For example, for e = -22, the two candidate floats around the exact value 1e-22 are:

9.999999682655225e-23   <- powf( 10.0f, -22.0f ) returns this
1.000000031374395e-22   <- but this one is closer to the exact 1e-22

Since this function's return values are powers of ten, using powf would make every input in those four decades return a value which is not the closest single-precision representation of a power of ten (and would also shift the rounding boundary at the midpoints). Computing in double-precision first is exact for all bits a float can hold, so (float)stdlib_base_pow( 10.0, e ) yields the correctly rounded power of ten for every exponent in the single-precision range (verified exhaustively for e in [-45, 38]).

Note this does not make the implementation "double-precision": the exponent search (log10f, floorf) is single-precision; pow is only used to generate the constants 10^e.

[anandkaranubc]

Ready to land in! Thanks @aryan7071 for working on it! 🚀

[kgryte]

LGTM