chore: use FLOAT64_MAX_SAFE_NTH_DOUBLE_FACTORIAL

[anandkaranubc]

Resolves None

Description

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This pull request:

• Completes the TODO on replacing the magic number with FLOAT64_MAX_SAFE_NTH_DOUBLE_FACTORIAL

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This pull request:

• resolves None

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---

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[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/factorial2	$194/194$ $+100.00\mathrm{\%}$	$19/19$ $+100.00\mathrm{\%}$	$2/2$ $+100.00\mathrm{\%}$	$194/194$ $+100.00\mathrm{\%}$

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

[Planeshifter]

Thanks, @anandkaranubc!

[stdlib-bot]

PR Commit Message

chore: use `FLOAT64_MAX_SAFE_NTH_DOUBLE_FACTORIAL`

PR-URL: https://github.com/stdlib-js/stdlib/pull/6363

Co-authored-by: Karan Anand <anandkarancompsci@gmail.com>
Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>

Please review the above commit message and make any necessary adjustments.

[anandkaranubc]

Thanks, @anandkaranubc!

Thanks for the review, @Planeshifter!

One quick question, I think we need to change the value of FLOAT64_MAX_SAFE_NTH_DOUBLE_FACTORIAL from 301 to 300..?

In [18]: base.factorial2(301) <= FLOAT64_MAX
Out[18]: false

In [19]: base.factorial2(300) <= FLOAT64_MAX
Out[19]: true

stdlib/lib/node_modules/@stdlib/constants/float64/max-safe-nth-double-factorial/lib/index.js

Line 44 in a77fb9e

var FLOAT64_MAX_SAFE_NTH_DOUBLE_FACTORIAL = 301|0; // eslint-disable-line id-length

Reference: factorial2(301) ≈ 1.13 × 10^309

In [34]: FLOAT64_MAX
Out[34]: 1.7976931348623157e+308

[Planeshifter]

@anandkaranubc I believe you are correct.

cc @gunjjoshi @kgryte, as this constant was added in https://github.com/stdlib-js/stdlib/pull/2966/files. Maybe the inlined definition of MAX_FACTORIAL2 here was the source of the value of 301, or how was the maximum double factorial safely representable within IEEE-754 double-precision floating-point limits determined?

[anandkaranubc]

The changes have been made according to the discussion in the OH.

cc: @Planeshifter @kgryte