feat: add `ml/strided/dkmeans-compute-inertia` by nakul-krishnakumar · Pull Request #13004 · stdlib-js/stdlib

nakul-krishnakumar · 2026-06-20T21:41:38Z

type: pre_commit_static_analysis_report
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task: lint_filenames status: passed
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Resolves a part of #12875.

Description

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This pull request:

Adds ml/strided/dkmeans-compute-inertia.

Related Issues

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This pull request has the following related issues:

[RFC]: Add batch machine learning algorithms in Javascript and C (tracking issue) #12875

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No.

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Read, understood, and followed the contributing guidelines.

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stdlib-bot · 2026-06-20T21:50:32Z

Coverage Report

Package	Statements	Branches	Functions	Lines
ml/strided/dkmeans-compute-inertia	$\\color{red}596/604$ $\\color{green}+98.68\\%$	$\\color{red}58/62$ $\\color{green}+93.55\\%$	$\\color{green}5/5$ $\\color{green}+100.00\\%$	$\\color{red}596/604$ $\\color{green}+98.68\\%$

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

kgryte · 2026-06-20T22:28:09Z

+* Compute inertia between double-precision floating-point centroids and data points.
+*
+* @private
+* @param {PositiveInteger} M - number of samples.


Suggested change

* @param {PositiveInteger} M - number of samples.

* @param {PositiveInteger} M - number of samples

Parameter descriptions should not end in periods. This is project convention. You should update all similar descriptions accordingly. This likely applies to your other PRs, as well.

kgryte · 2026-06-20T22:29:16Z

+* @param {Float64Array} C - strided array centroid locations.
+* @param {integer} sc1 - stride length of first dimension of c.
+* @param {integer} sc2 - stride length of second dimension of c.
+* @param {integer} oc - initial index of centroids.


Suggested change

* @param {integer} oc - initial index of centroids.

* @param {integer} oc - starting index of `C`

Use consistent descriptions.

kgryte · 2026-06-20T22:29:48Z

+* @param {integer} oc - initial index of centroids.
+* @param {Int32Array} labels - labels array containing cluster index of each data point.
+* @param {integer} sl - stride length of labels.
+* @param {integer} ol - initial index of labels.


Suggested change

* @param {integer} ol - initial index of labels.

* @param {integer} ol - starting index of `labels`

In JS parameter descriptions, we place references to other parameter names in backticks.

kgryte · 2026-06-20T22:39:58Z

+	if ( metric === 'sqeuclidean' ) {
+		dist = dsquaredEuclidean;
+	} else if ( metric === 'correlation' ) {
+		dist = dcorrelation;
+	} else if ( metric === 'cityblock' ) {
+		dist = dcityblock;
+	} else {
+		dist = dcosine;
+	}


IIRC, this sort of nested conditional occurs elsewhere. In which case, I am wondering if it would be better to create a package ml/strided/dkmeans-metric2strided (different name?). We kind of have precedent elsewhere (see https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/ctors). The API would be

var TABLE = { 'sqeuclidean': dsquaredEuclidean, 'correlation': dcorrelation, 'cityblock': dcityblock, 'cosine': dcosine }; function metric2strided( metric ) { return TABLE[ metric ] || null; }

Then, in this implementation, the conditional becomes

// ... dist = metric2strided( metric ); // ...

where we assume that metric is a recognized metric.

kgryte · 2026-06-20T22:41:43Z

I think this package needs to be renamed: dkmeans-inertia. The use of compute in the name is redundant, IMO. Your API alias then becomes dkmeansInertia.

kgryte · 2026-06-20T22:46:58Z

+	CBLAS_INT i;
+	double d;
+
+	if ( metric == STDLIB_ML_KMEANS_SQEUCLIDEAN ) {


In contrast to JS, I don't think there is a "nice" way of abstracting this logic out into a separate function/macro, as then we'd need to make the func_type public, etc. So, I believe we are left with inlining, as done here.

kgryte · 2026-06-20T22:47:21Z

+}
+
+/**
+* Compute inertia between double-precision floating-point centroids and data points using alternative indexing semantics.


Suggested change

* Compute inertia between double-precision floating-point centroids and data points using alternative indexing semantics.

* Computes the inertia between double-precision floating-point centroids and data points using alternative indexing semantics.

kgryte · 2026-06-20T22:47:31Z

+typedef double func_type( const CBLAS_INT N, const double *X, const CBLAS_INT sx, const CBLAS_INT ox, const double *Y, const CBLAS_INT strideY, const CBLAS_INT offsetY );
+
+/**
+* Compute inertia between double-precision floating-point centroids and data points.


Suggested change

* Compute inertia between double-precision floating-point centroids and data points.

* Computes the inertia between double-precision floating-point centroids and data points.

kgryte · 2026-06-20T22:48:45Z

+#include <stdint.h>
+
+/**
+* Data type to store distance metric function.


Suggested change

* Data type to store distance metric function.

* Type definition for a function which computes a distance metric for an input strided array.

kgryte

Left initial comments.

nakul-krishnakumar requested a review from a team June 20, 2026 21:41

stdlib-bot added the Needs Review A pull request which needs code review. label Jun 20, 2026

nakul-krishnakumar added Machine Learning Issue or pull request specific to machine learning functionality. GSoC Google Summer of Code. gsoc: 2026 Google Summer of Code (2026). labels Jun 20, 2026

kgryte reviewed Jun 20, 2026

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kgryte added Needs Changes Pull request which needs changes before being merged. and removed Needs Review A pull request which needs code review. labels Jun 20, 2026

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feat: add `ml/strided/dkmeans-compute-inertia`#13004

feat: add `ml/strided/dkmeans-compute-inertia`#13004
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nakul-krishnakumar:compute-inertia

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	* @param {PositiveInteger} M - number of samples.
	* @param {PositiveInteger} M - number of samples

	* @param {integer} oc - initial index of centroids.
	* @param {integer} oc - starting index of `C`

	* @param {integer} ol - initial index of labels.
	* @param {integer} ol - starting index of `labels`

	* Compute inertia between double-precision floating-point centroids and data points using alternative indexing semantics.
	* Computes the inertia between double-precision floating-point centroids and data points using alternative indexing semantics.

	* Data type to store distance metric function.
	* Type definition for a function which computes a distance metric for an input strided array.

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nakul-krishnakumar commented Jun 20, 2026

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kgryte Jun 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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