feat: add C implementation for `blas/ext/base/ndarray/ztril` by yb175 · Pull Request #16063 · stdlib-js/stdlib

yb175 · 2026-10-11T13:20:41Z

Related to #14819.

Description

What is the purpose of this pull request?

This pull request:

Adds a native C ndarray implementation for blas/ext/base/ndarray/ztril, using the existing strided C routine.
Adds the Node.js addon and uses the native implementation when available, with the JavaScript implementation as a fallback.
Adds native tests, benchmarks, a C example, and C API documentation.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

[RFC]: add C implementations for blas/ext/base/ndarray packages #14819

Questions

Any questions for reviewers of this pull request?

The native JS wrapper extracts k from the generic scalar ndarray and passes a float64 scalar ndarray to C, so the existing JS example works. For direct C callers, should stdlib_blas_ext_ztril require a 0-D float64 ndarray for k, or support other numeric dtypes? Since the C function returns void, how would you prefer it to handle an unsupported dtype or unreadable scalar?

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 codex for tests generation and documentation writing , all the changes made by ai are reviewed carefully

@stdlib-js/reviewers

stdlib-bot · 2026-10-11T13:32:50Z

Coverage Report

Package	Statements	Branches	Functions	Lines
blas/ext/base/ndarray/ztril	$\\color{green}227/227$ $\\color{green}+0.00\\%$	$\\color{green}7/7$ $\\color{green}+0.00\\%$	$\\color{green}2/2$ $\\color{green}+0.00\\%$	$\\color{green}227/227$ $\\color{green}+0.00\\%$

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

AryanSharma48 · 2026-10-13T21:24:01Z

+<section class="notes">
+
+-   Elements outside of the copied region are left unchanged.
+
+</section>


Suggested change

<section class="notes">

- Elements outside of the copied region are left unchanged.

</section>

<section class="notes">

### Notes

- Elements outside of the copied region are left unchanged.

</section>

Whenever <section class="notes"> in the C APIs section contains text, it must include a ### Notes heading right after opening the tag (see e.g. znancount/README.md and zany/README.md).

kgryte · 2026-10-13T21:40:30Z

+		stdlib_blas_ext_ztril( arrays );
+	}
+	elapsed = tic() - t;
+	for ( j = 0; j < len; j++ ) {
+		parts.value = dataB[ j ];
+		if ( isnan( parts.parts[ 0 ] ) || isnan( parts.parts[ 1 ] ) ) {
+			fprintf( stderr, "should not return NaN\n" );
+			break;
+		}
+	}


This is not what is desired. You a) need to retain an assertion check within the hot loop and b) should be using functional accessors, such as complex/float64/real and complex/float64/imag.

yb175 · 2026-10-14T07:50:34Z

Thanks for the feedback. I added the ### Notes heading and moved the NaN check into the benchmark’s hot loop, using the complex/float64/real and complex/float64/imag accessors. Please let me know if anything else is needed!

yb175 · 2026-10-14T11:18:08Z

while reviewing the implementation I made few changes following merged PRs convention

switched k to an int32 ndarray throughout the package. following the discussion in feat: add C implementation blas/ext/base/ndarray/dtril #14471
updated C examples to use stlib_complex128_t buffers
added browser fallback in package.json
Made the C benchmark report a TAP failure if NaN is detected
updated the native Js benchmark check both real and imaginary components

ujjwalv01 · 2026-10-14T13:39:56Z

@yb175 , Left a few suggestions, PTAL;

kgryte · 2026-10-14T13:43:52Z

@yb175 In general, you need to pay much closer attention to how other packages are structured. Only the minimal essential changes should be present among separate similar packages.

yb175 · 2026-10-14T13:56:03Z

@yb175 In general, you need to pay much closer attention to how other packages are structured. Only the minimal essential changes should be present among separate similar packages.

Thanks @kgryte for the feedback , from next time I would carefully observe the merged PRs from the similar packages before opening future PRs 😊

ujjwalv01 · 2026-10-14T14:16:45Z

 * // returns true
 */
-declare function ztril( arrays: [ complex128ndarray, complex128ndarray, typedndarray<number> ] ): complex128ndarray;
+declare function ztril( arrays: [ complex128ndarray, complex128ndarray, int32ndarray ] ): complex128ndarray;


@kgryte Is it okay for k to be int32ndarray here as well ?

yb175 · 2026-10-14T18:16:59Z

addressed all other review suggestions . leaving the int32ndarray type question open until I get @kgryte guidance , Then I will follow up with that change .

ujjwalv01 · 2026-10-15T02:08:00Z

+var bench = require( '@stdlib/bench' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var format = require( '@stdlib/string/format' );
+var Complex128Matrix = require( '@stdlib/ndarray/matrix/complex128' );
+var uniform = require( '@stdlib/random/array/uniform' );
+var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var real = require( '@stdlib/complex/float64/real' );
+var tryRequire = require( '@stdlib/utils/try-require' );


Keep the same order as benchmark.js.

Suggested change

var bench = require( '@stdlib/bench' );

var pow = require( '@stdlib/math/base/special/pow' );

var format = require( '@stdlib/string/format' );

var Complex128Matrix = require( '@stdlib/ndarray/matrix/complex128' );

var uniform = require( '@stdlib/random/array/uniform' );

var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );

var isnan = require( '@stdlib/math/base/assert/is-nan' );

var real = require( '@stdlib/complex/float64/real' );

var tryRequire = require( '@stdlib/utils/try-require' );

var bench = require( '@stdlib/bench' );

var uniform = require( '@stdlib/random/array/uniform' );

var Complex128Matrix = require( '@stdlib/ndarray/matrix/complex128' );

var isnan = require( '@stdlib/math/base/assert/is-nan' );

var real = require( '@stdlib/complex/float64/real' );

var pow = require( '@stdlib/math/base/special/pow' );

var format = require( '@stdlib/string/format' );

var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );

var tryRequire = require( '@stdlib/utils/try-require' );

ujjwalv01 · 2026-10-15T02:08:16Z

+var ztril = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( ztril instanceof Error )
+};


Suggested change

var ztril = tryRequire( resolve( __dirname, './../lib/native.js' ) );

var opts = {

'skip': ( ztril instanceof Error )

};

var ztril = tryRequire( resolve( __dirname, './../lib/native.js' ) );

var opts = {

'skip': ( ztril instanceof Error )

};

var options = {

'dtype': 'float64'

};

ujjwalv01 · 2026-10-15T02:08:21Z

+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} N - number of rows and columns


Suggested change

* @param {PositiveInteger} N - number of rows and columns

* @param {PositiveInteger} N - number of elements along each dimension

ujjwalv01 · 2026-10-15T02:09:06Z

+	abuf = uniform( N*N*2, -100.0, 100.0, {
+		'dtype': 'float64'
+	});
+	bbuf = uniform( N*N*2, -100.0, 100.0, {
+		'dtype': 'float64'
+	});
+	A = new Complex128Matrix( abuf.buffer, 0, N, N );
+	B = new Complex128Matrix( bbuf.buffer, 0, N, N );


Suggested change

abuf = uniform( N*N*2, -100.0, 100.0, {

'dtype': 'float64'

});

bbuf = uniform( N*N*2, -100.0, 100.0, {

'dtype': 'float64'

});

A = new Complex128Matrix( abuf.buffer, 0, N, N );

B = new Complex128Matrix( bbuf.buffer, 0, N, N );

abuf = uniform( N*N*2, -100.0, 100.0, options );

bbuf = uniform( N*N*2, -100.0, 100.0, options );

A = new Complex128Matrix( abuf.buffer, 0, N, N );

B = new Complex128Matrix( bbuf.buffer, 0, N, N );

ujjwalv01

Looks good to me;

cc : @kgryte

feat: add C implementation for blas/ext/base/ndarray/ztril

9db7165

yb175 requested a review from a team October 11, 2026 13:20

Merge branch 'develop' into feat/ndarray-ztril-c

d3177f2

stdlib-bot added BLAS Issue or pull request related to Basic Linear Algebra Subprograms (BLAS). Needs Review A pull request which needs code review. labels Oct 11, 2026

yb175 added 2 commits October 11, 2026 13:41

fix: address ztril CI lint failures

24c00e2

fix : add TAP plan comment

bf66638

AryanSharma48 reviewed Oct 13, 2026

View reviewed changes

kgryte reviewed Oct 13, 2026

View reviewed changes

kgryte added Needs Changes Pull request which needs changes before being merged. and removed Needs Review A pull request which needs code review. labels Oct 13, 2026

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fix: address review feedback

6159e8c

fix: align ztril native implementation with conventions

32f1bc6

yb175 added 2 commits October 14, 2026 11:21

fix : fixed the ci failure

d4fbd6f

fix: wrap ztril REPL help text to satisfy lint

1dc85ec