feat: add C ndarray interface and refactor implementation for stats/base/svariancepn

[0PrashantYadav0]

---

type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes. report:

• task: lint_filenames status: passed
• task: lint_editorconfig status: passed
• task: lint_markdown status: passed
• task: lint_package_json status: na
• task: lint_repl_help status: passed
• task: lint_javascript_src status: passed
• task: lint_javascript_cli status: na
• task: lint_javascript_examples status: na
• task: lint_javascript_tests status: passed
• task: lint_javascript_benchmarks status: passed
• task: lint_python status: na
• task: lint_r status: na
• task: lint_c_src status: passed
• task: lint_c_examples status: passed
• task: lint_c_benchmarks status: passed
• task: lint_c_tests_fixtures status: na
• task: lint_shell status: na
• task: lint_typescript_declarations status: passed
• task: lint_typescript_tests status: na
• task: lint_license_headers status: passed ---

---

type: pre_push_report
description: Results of running various checks prior to pushing changes. report:

• task: run_javascript_examples status: na
• task: run_c_examples status: na
• task: run_cpp_examples status: na
• task: run_javascript_readme_examples status: na
• task: run_c_benchmarks status: na
• task: run_cpp_benchmarks status: na
• task: run_fortran_benchmarks status: na
• task: run_javascript_benchmarks status: na
• task: run_julia_benchmarks status: na
• task: run_python_benchmarks status: na
• task: run_r_benchmarks status: na
• task: run_javascript_tests status: na ---

Resolves None.

Description

What is the purpose of this pull request?

This pull request:

• adds C ndarray interface for stats/base/svariancepn
• refactors JavaScript implementation
• updates tests, docs, examples and benchmarks

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves None.

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.

No.

Checklist

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

• Read, understood, and followed the contributing guidelines.

---

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/svariancepn	$\color{green}396/396$ $\color{green}+100.00\%$	$\color{green}21/21$ $\color{green}+100.00\%$	$\color{green}4/4$ $\color{green}+100.00\%$	$\color{green}396/396$ $\color{green}+100.00\%$

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

[0PrashantYadav0]

@Planeshifter Please review and merge

[0PrashantYadav0]

@kgryte Made all the changes you asked for. please review and merge.