feat: add `lapack/base/dlaisnan` by iampratik13 · Pull Request #12183 · stdlib-js/stdlib

iampratik13 · 2026-05-17T19:03:23Z

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task: lint_filenames status: passed
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Resolves none.

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feat: add lapack/base/dlaisnan

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--- 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: passed - task: lint_repl_help status: passed - task: lint_javascript_src status: passed - task: lint_javascript_cli status: na - task: lint_javascript_examples status: passed - 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: 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: passed - task: lint_license_headers status: passed ---

stdlib-bot · 2026-05-17T19:06:16Z

Coverage Report

Package	Statements	Branches	Functions	Lines
lapack/base/dlaisnan	$\color{green}96/96$ $\color{green}+0.00%$	$\color{green}3/3$ $\color{green}+0.00%$	$\color{green}1/1$ $\color{green}+0.00%$	$\color{green}96/96$ $\color{green}+0.00%$

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

iampratik13 · 2026-05-17T19:08:59Z

/stdlib update-copyright-years

anandkaranubc · 2026-05-17T19:35:30Z

-		if ( typeof out !== 'number' ) {
-			b.fail( 'should return a number' );
+		z = dlaisnan( x[ i % len ], y[ i % len ] );
+		if ( isnan( z ) ) {


dlaisnan returns a boolean, but this benchmark uses @stdlib/math/base/assert/is-nan on the result. isnan(true) / isnan(false) are always false, so this guard never fails and doesn’t validate the return type.

Please follow the pattern in @stdlib/math/base/assert/is-nan/benchmark/benchmark.js

anandkaranubc · 2026-05-17T19:42:34Z

 /**
-* Reinterpret a `Float16Array` as a `Uint16Array`.
+* Tests whether two double-precision floating-point arguments are unequal and thus at least one is NaN.


The summary says the function tests inequality “and thus at least one is NaN.” That’s only true when both arguments are the same value

For dlaisnan(1.0, 2.0) the result is true with no NaN involved.

anandkaranubc · 2026-05-17T19:44:37Z

 /**
-* Reinterpret a `Float16Array` as a `Uint16Array`.
+* Tests whether two double-precision floating-point arguments are unequal and thus at least one is NaN.


Suggested change

* Tests whether two double-precision floating-point arguments are unequal and thus at least one is NaN.

* Tests input for NaN by comparing two double-precision floating-point arguments for inequality.

I think leaving it as this, is better. Thoughts?

+This change applies throughout the PR

anandkaranubc · 2026-05-17T19:50:33Z

-* @example
-* var Float16Array = require( '@stdlib/array/float16' );
-* var reinterpret = require( '@stdlib/strided/base/reinterpret-float16' );
+* -   This routine exists solely to avoid over-optimization in DISNAN.


Suggested change

* - This routine exists solely to avoid over-optimization in DISNAN.

* - This routine exists solely to avoid over-optimization in `disnan`.

anandkaranubc · 2026-05-17T19:53:51Z

+## Notes
+
+-   `dlaisnan()` corresponds to the [LAPACK][LAPACK] auxiliary routine [`dlaisnan`][lapack-dlaisnan].
+-   This routine is not for general use. It exists solely to avoid over-optimization in `disnan`.


Let's add a link to lapack isnan too

[lapack-disnan]: https://www.netlib.org/lapack/explore-html/d0/d4c/group__isnan_ga7aa3164d5df8d883754b0a70e9c7209c.html

anandkaranubc · 2026-05-17T19:56:36Z

 <section class="notes">

+## Notes
+
+-   `dlaisnan()` corresponds to the [LAPACK][LAPACK] auxiliary routine [`dlaisnan`][lapack-dlaisnan].


Suggested change

- `dlaisnan()` corresponds to the [LAPACK][LAPACK] auxiliary routine [`dlaisnan`][lapack-dlaisnan].

- `dlaisnan()` corresponds to the [LAPACK][lapack] auxiliary routine [`dlaisnan`][lapack-dlaisnan].

anandkaranubc · 2026-05-17T19:58:32Z

+
+-   `dlaisnan()` corresponds to the [LAPACK][LAPACK] auxiliary routine [`dlaisnan`][lapack-dlaisnan].
+-   This routine is not for general use. It exists solely to avoid over-optimization in `disnan`.
+-   `dlaisnan` checks for NaNs by comparing its two arguments for inequality. `NaN` is the only floating-point value where `NaN != NaN` returns `true`. To check for NaNs, pass the same variable as both arguments (i.e., `dlaisnan( x, x )`).


Suggested change

- `dlaisnan` checks for NaNs by comparing its two arguments for inequality. `NaN` is the only floating-point value where `NaN != NaN` returns `true`. To check for NaNs, pass the same variable as both arguments (i.e., `dlaisnan( x, x )`).

- `dlaisnan` checks for NaNs by comparing its two arguments for inequality. `NaN` is the only floating-point value where `NaN !== NaN` returns `true`. To check for NaNs, pass the same variable as both arguments (i.e., `dlaisnan( x, x )`).

anandkaranubc · 2026-05-17T19:58:40Z

+-   `dlaisnan()` corresponds to the [LAPACK][LAPACK] auxiliary routine [`dlaisnan`][lapack-dlaisnan].
+-   This routine is not for general use. It exists solely to avoid over-optimization in `disnan`.
+-   `dlaisnan` checks for NaNs by comparing its two arguments for inequality. `NaN` is the only floating-point value where `NaN != NaN` returns `true`. To check for NaNs, pass the same variable as both arguments (i.e., `dlaisnan( x, x )`).
+-   The function returns `true` whenever the two arguments are unequal, not only when one is NaN. This matches the Fortran reference implementation which simply returns `DIN1.NE.DIN2`.


Suggested change

- The function returns `true` whenever the two arguments are unequal, not only when one is NaN. This matches the Fortran reference implementation which simply returns `DIN1.NE.DIN2`.

- The function returns `true` whenever the two arguments are unequal, not only when one is `NaN`. This matches the Fortran reference implementation which simply returns `DIN1.NE.DIN2`.

anandkaranubc · 2026-05-17T20:01:40Z

I think we can also include

tape( 'the function returns expected values when passed the same variable as both arguments', function test( t ) { var x; var bool; x = NaN; bool = dlaisnan( x, x ); t.strictEqual( bool, true, 'returns expected value' ); x = 5.0; bool = dlaisnan( x, x ); t.strictEqual( bool, false, 'returns expected value' ); x = 0.0; bool = dlaisnan( x, x ); t.strictEqual( bool, false, 'returns expected value' ); x = -0.0; bool = dlaisnan( x, x ); t.strictEqual( bool, false, 'returns expected value' ); x = PINF; bool = dlaisnan( x, x ); t.strictEqual( bool, false, 'returns expected value' ); t.end(); });

LAPACK documents NaN detection as passing the same variable twice: dlaisnan(x, x). The current tests use literals (e.g. dlaisnan(NaN, NaN) and dlaisnan(5.0, 5.0)), which don’t exercise that pattern or guard against an engine folding x === x.

anandkaranubc · 2026-05-17T20:07:21Z

+* @param {number} DIN1 - first number to compare
+* @param {number} DIN2 - second number to compare


Suggested change

* @param {number} DIN1 - first number to compare

* @param {number} DIN2 - second number to compare

* @param {number} DIN1 - first input number

* @param {number} DIN2 - second input number

Applies to other related files too.

iampratik13 requested a review from a team May 17, 2026 19:03

stdlib-bot added LAPACK Issue or pull request related to the Linear Algebra Package (LAPACK). Needs Review A pull request which needs code review. labels May 17, 2026

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chore: update copyright years

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	* Tests whether two double-precision floating-point arguments are unequal and thus at least one is NaN.
	* Tests input for NaN by comparing two double-precision floating-point arguments for inequality.

	* - This routine exists solely to avoid over-optimization in DISNAN.
	* - This routine exists solely to avoid over-optimization in `disnan`.

	- `dlaisnan()` corresponds to the [LAPACK][LAPACK] auxiliary routine [`dlaisnan`][lapack-dlaisnan].
	- `dlaisnan()` corresponds to the [LAPACK][lapack] auxiliary routine [`dlaisnan`][lapack-dlaisnan].

	- `dlaisnan` checks for NaNs by comparing its two arguments for inequality. `NaN` is the only floating-point value where `NaN != NaN` returns `true`. To check for NaNs, pass the same variable as both arguments (i.e., `dlaisnan( x, x )`).
	- `dlaisnan` checks for NaNs by comparing its two arguments for inequality. `NaN` is the only floating-point value where `NaN !== NaN` returns `true`. To check for NaNs, pass the same variable as both arguments (i.e., `dlaisnan( x, x )`).

	- The function returns `true` whenever the two arguments are unequal, not only when one is NaN. This matches the Fortran reference implementation which simply returns `DIN1.NE.DIN2`.
	- The function returns `true` whenever the two arguments are unequal, not only when one is `NaN`. This matches the Fortran reference implementation which simply returns `DIN1.NE.DIN2`.

		* @param {number} DIN1 - first number to compare
		* @param {number} DIN2 - second number to compare

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