feat: add `ml/strided/dkmeans-init-plus-plus` by nakul-krishnakumar · Pull Request #12312 · stdlib-js/stdlib

nakul-krishnakumar · 2026-05-27T07:35:32Z

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_pkg_readmes status: na
task: lint_markdown_docs status: na
task: lint_markdown status: na
task: lint_package_json status: na
task: lint_repl_help status: na
task: lint_javascript_src status: passed
task: lint_javascript_cli status: na
task: lint_javascript_examples status: na
task: lint_javascript_tests status: na
task: lint_javascript_benchmarks status: na
task: lint_python status: na
task: lint_r status: na
task: lint_c_src status: na
task: lint_c_examples status: na
task: lint_c_benchmarks status: na
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 ---

Resolves None.

Description

What is the purpose of this pull request?

This pull request:

Adds ml/strided/dkmeans-init-plus-plus.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

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.

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

If you answered "yes" to using AI assistance, please provide a short disclosure indicating how you used AI assistance. This helps reviewers determine how much scrutiny to apply when reviewing your contribution. Example disclosures: "This PR was written primarily by Claude Code." or "I consulted ChatGPT to understand the codebase, but the proposed changes were fully authored manually by myself.".

I used Claude Code to compare the implementation with ml/incr/kmeans/lib/init_kmeansplusplus and existing strided blas implementations, but the proposed changes were fully authored manually by myself.

@stdlib-js/reviewers

--- 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_pkg_readmes status: na - task: lint_markdown_docs status: na - task: lint_markdown status: na - task: lint_package_json status: na - task: lint_repl_help status: na - task: lint_javascript_src status: passed - task: lint_javascript_cli status: na - task: lint_javascript_examples status: na - task: lint_javascript_tests status: na - task: lint_javascript_benchmarks status: na - task: lint_python status: na - task: lint_r status: na - task: lint_c_src status: na - task: lint_c_examples status: na - task: lint_c_benchmarks status: na - 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 ---

nakul-krishnakumar · 2026-05-27T07:36:48Z

+* Initializes centroids by performing the k-means++ initialization procedure.
+*
+* ## Method
+*
+* The k-means++ algorithm for choosing initial centroids is as follows:
+*
+* 1.  Select a data point uniformly at random from a data set \\( X \\). This data point is first centroid and denoted \\( c_0 \\).
+*
+* 2.  Compute the distance from each data point to \\( c_0 \\). Denote the distance between \\( c_j \\) and data point \\( m \\) as \\( d(x_m, c_j) \\).
+*
+* 3.  Select the next centroid, \\( c_1 \\), at random from \\( X \\) with probability
+*
+*     ```tex
+*     \frac{d^2(x_m, c_0)}{\sum_{j=0}^{n-1} d^2(x_j, c_0)}
+*     ```
+*
+*     where \\( n \\) is the number of data points.
+*
+* 4.  To choose centroid \\( j \\),
+*
+*     a.   Compute the distances from each data point to each centroid and assign each data point to its closest centroid.
+*
+*     b.   For \\( i = 0,\ldots,n-1 \\) and \\( p = 0,\ldots,j-2 \\), select centroid \\( j \\) at random from \\( X \\) with probability
+*
+*          ```tex
+*          \frac{d^2(x_i, c_p)}{\sum_{\{h; x_h \exits C_p\}} d^2(x_h, c_p)}
+*          ```
+*
+*          where \\( C_p \\) is the set of all data points closest to centroid \\( c_p \\) and \\( x_i \\) belongs to \\( c_p \\).
+*
+*          Stated more plainly, select each subsequent centroid with a probability proportional to the distance from the centroid to the closest centroid already chosen.
+*
+* 5.  Repeat step `4` until \\( k \\) centroids have been chosen.
+*
+* ## References
+*
+* -   Arthur, David, and Sergei Vassilvitskii. 2007. "K-means++: The Advantages of Careful Seeding." In _Proceedings of the Eighteenth Annual Acm-Siam Symposium on Discrete Algorithms_, 1027–35. SODA '07. Philadelphia, PA, USA: Society for Industrial and Applied Mathematics. <http://dl.acm.org/citation.cfm?id=1283383.1283494>.
+*


I am not sure on which all files I should write this description, please guide me on this.

nakul-krishnakumar · 2026-05-27T07:38:15Z

+* ]);
+*
+* var v = dkmeansInitPlusPlus( 'row-major', k, M, N, out, 2, xbuf, 2, 'sqeuclidean', 3, 44 );
+* // returns <Float64Array>[0,0,1,-1,1,1]


I hope this return value makes sense. As the user already has the strides it should be easy for them to access it, also the user is expected to pass in an empty initialized out array which will be filled with the flat centroids array.

nakul-krishnakumar · 2026-05-27T07:40:33Z

+	// Create a scratch array for storing cumulative probabilities:
+	probs = new Float64Array( M );
+
+	// 2-5. For each data point, compute the distances to each centroid, find the closest centroid, and, based on the distance to the closest centroid, assign a probability to the data point to be chosen as centroid `c_j`...


Please note that all these comments in this implementation is directly referenced from ml/incr/kmeans/lib/init_kmeansplusplus

--- 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_pkg_readmes status: na - task: lint_markdown_docs status: na - task: lint_markdown status: na - task: lint_package_json status: na - task: lint_repl_help status: na - task: lint_javascript_src status: passed - task: lint_javascript_cli status: na - task: lint_javascript_examples status: na - task: lint_javascript_tests status: na - task: lint_javascript_benchmarks status: na - task: lint_python status: na - task: lint_r status: na - task: lint_c_src status: na - task: lint_c_examples status: na - task: lint_c_benchmarks status: na - 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_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_pkg_readmes status: na - task: lint_markdown_docs status: na - task: lint_markdown status: na - task: lint_package_json status: na - task: lint_repl_help status: na - task: lint_javascript_src status: na - task: lint_javascript_cli status: na - task: lint_javascript_examples status: na - task: lint_javascript_tests status: passed - task: lint_javascript_benchmarks status: na - task: lint_python status: na - task: lint_r status: na - task: lint_c_src status: na - task: lint_c_examples status: na - task: lint_c_benchmarks status: na - 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_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_pkg_readmes status: na - task: lint_markdown_docs status: na - task: lint_markdown status: na - task: lint_package_json status: na - task: lint_repl_help status: na - task: lint_javascript_src status: na - task: lint_javascript_cli status: na - task: lint_javascript_examples status: na - task: lint_javascript_tests status: na - task: lint_javascript_benchmarks status: passed - task: lint_python status: na - task: lint_r status: na - task: lint_c_src status: na - task: lint_c_examples status: na - task: lint_c_benchmarks status: na - 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 ---

nakul-krishnakumar · 2026-05-27T17:11:20Z

/stdlib merge

…nspp

--- 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_pkg_readmes status: na - task: lint_markdown_docs status: na - task: lint_markdown status: na - task: lint_package_json status: na - task: lint_repl_help status: na - task: lint_javascript_src status: passed - task: lint_javascript_cli status: na - task: lint_javascript_examples status: na - task: lint_javascript_tests status: na - task: lint_javascript_benchmarks status: na - task: lint_python status: na - task: lint_r status: na - task: lint_c_src status: na - task: lint_c_examples status: na - task: lint_c_benchmarks status: na - 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 ---

nakul-krishnakumar · 2026-05-27T17:45:56Z

+	if ( trials < 1 ) {
+		throw new TypeError( format( 'invalid argument. Thirteenth argument must be a valid trials (>=1). Value: `%s`.', trials ) );
+	}


Would it be better to just return NaN?

stdlib-bot · 2026-05-27T17:46:28Z

Coverage Report

Package	Statements	Branches	Functions	Lines
ml/strided/dkmeans-init-plus-plus	$\color{red}519/537$ $\color{green}+96.65%$	$\color{red}38/44$ $\color{green}+86.36%$	$\color{green}2/2$ $\color{green}+100.00%$	$\color{red}519/537$ $\color{green}+96.65%$

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

nakul-krishnakumar · 2026-05-27T17:48:07Z

+	if ( k < 1 || M < 1 || N < 1) {
+		return NaN;
+	}


Is this necessary?

As it is a low-level kernel, we can expect user to pass in valid parameters.

But if this check is not kept, for invalid params the API return <Float64Array>[ NaN, NaN, NaN, ..., NaN ].

nakul-krishnakumar requested a review from a team May 27, 2026 07:35

nakul-krishnakumar marked this pull request as draft May 27, 2026 07:35

stdlib-bot added Needs Review A pull request which needs code review. and removed Needs Review A pull request which needs code review. labels May 27, 2026

nakul-krishnakumar commented May 27, 2026

View reviewed changes

nakul-krishnakumar added 3 commits May 27, 2026 13:15

nakul-krishnakumar mentioned this pull request May 27, 2026

Weekly Standup (2026-05-25) stdlib-js/meetings#127

Open

stdlib-bot added the bot: In Progress Pull request is currently awaiting automation. label May 27, 2026

Merge remote-tracking branch 'upstream/develop' into ml-strided-dkmea…

b75757a

…nspp

stdlib-bot removed the bot: In Progress Pull request is currently awaiting automation. label May 27, 2026

nakul-krishnakumar commented May 27, 2026

View reviewed changes

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

feat: add `ml/strided/dkmeans-init-plus-plus`#12312

feat: add `ml/strided/dkmeans-init-plus-plus`#12312
nakul-krishnakumar wants to merge 6 commits into
stdlib-js:developfrom
nakul-krishnakumar:ml-strided-dkmeanspp

nakul-krishnakumar commented May 27, 2026

Uh oh!

nakul-krishnakumar May 27, 2026

Uh oh!

nakul-krishnakumar May 27, 2026

Uh oh!

nakul-krishnakumar May 27, 2026

Uh oh!

nakul-krishnakumar commented May 27, 2026

Uh oh!

nakul-krishnakumar May 27, 2026

Uh oh!

stdlib-bot commented May 27, 2026

Uh oh!

nakul-krishnakumar May 27, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Uh oh!

Conversation

nakul-krishnakumar commented May 27, 2026

Description

Related Issues

Questions

Other

Checklist

AI Assistance

Disclosure

Uh oh!

nakul-krishnakumar May 27, 2026

Choose a reason for hiding this comment

Uh oh!

nakul-krishnakumar May 27, 2026

Choose a reason for hiding this comment

Uh oh!

nakul-krishnakumar May 27, 2026

Choose a reason for hiding this comment

Uh oh!

nakul-krishnakumar commented May 27, 2026

Uh oh!

nakul-krishnakumar May 27, 2026

Choose a reason for hiding this comment

Uh oh!

stdlib-bot commented May 27, 2026

Coverage Report

Uh oh!

nakul-krishnakumar May 27, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants