feat: add lapack/base/dlaisnan

lib/node_modules/@stdlib/lapack/base/dlaisnan/README.md

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+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2026 The Stdlib Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+-->
+
+# dlaisnan
+
+> LAPACK auxiliary routine to test input for NaN by comparing two double-precision floating-point arguments for inequality.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var dlaisnan = require( '@stdlib/lapack/base/dlaisnan' );
+```
+
+#### dlaisnan( DIN1, DIN2 )
+
+Tests whether two double-precision floating-point arguments are unequal and thus at least one is NaN.
+
+```javascript
+var bool = dlaisnan( NaN, NaN );
+// returns true
+
+bool = dlaisnan( NaN, 5.0 );
+// returns true
+
+bool = dlaisnan( 5.0, 5.0 );
+// returns false
+```
+
+The function has the following parameters:
+
+-   **DIN1**: first number to compare.
+-   **DIN2**: second number to compare.
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## 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`.
+-   `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`.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
+var logEachMap = require( '@stdlib/console/log-each-map' );
+var dlaisnan = require( '@stdlib/lapack/base/dlaisnan' );
+
+var opts = {
+    'dtype': 'float64'
+};
+var x = discreteUniform( 100, -50, 50, opts );
+var y = discreteUniform( 100, -50, 50, opts );
+
+logEachMap( 'dlaisnan( %d, %d ) = %s', x, y, dlaisnan );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- C usage documentation. -->
+
+<section class="usage">
+
+### Usage
+
+```c
+TODO
+```
+
+#### TODO
+
+TODO.
+
+```c
+TODO
+```
+
+TODO
+
+```c
+TODO
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- C API usage examples. -->
+
+<section class="examples">
+
+### Examples
+
+```c
+TODO
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="links">
+
+[lapack]: https://www.netlib.org/lapack/explore-html/
+
+[lapack-dlaisnan]: https://www.netlib.org/lapack/explore-html/d3/d22/group__laisnan_gad49d1fe3d6890e9c4f60e0429abab3c9.html
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/lapack/base/dlaisnan/benchmark/benchmark.js

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+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+'use strict';
+
+// MODULES //
+
+var bench = require( '@stdlib/bench' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var uniform = require( '@stdlib/random/array/uniform' );
+var pkg = require( './../package.json' ).name;
+var dlaisnan = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var len;
+	var x;
+	var y;
+	var z;
+	var i;
+
+	len = 100;
+	x = uniform( len, -50, 50 );
+	y = uniform( len, -50, 50 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		z = dlaisnan( x[ i % len ], y[ i % len ] );
+		if ( isnan( z ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnan( z ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/lapack/base/dlaisnan/docs/repl.txt

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+
+{{alias}}( DIN1, DIN2 )
+    Tests whether two double-precision floating-point arguments are unequal
+    and thus at least one is NaN.
+
+    Parameters
+    ----------
+    DIN1: number
+        First number to compare.
+
+    DIN2: number
+        Second number to compare.
+
+    Returns
+    -------
+    bool: boolean
+        Boolean indicating whether the arguments are unequal.
+
+    Examples
+    --------
+    > var bool = {{alias}}( NaN, NaN )
+    true
+    > bool = {{alias}}( NaN, 5.0 )
+    true
+    > bool = {{alias}}( 5.0, 5.0 )
+    false
+
+    See Also
+    --------

lib/node_modules/@stdlib/lapack/base/dlaisnan/docs/types/index.d.ts

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+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+// TypeScript Version: 4.1
+
+/**
+* LAPACK auxiliary routine to test input for NaN by comparing two double-precision floating-point arguments for inequality.
+*
+* @param DIN1 - first number to compare
+* @param DIN2 - second number to compare
+* @returns boolean indicating whether the arguments are unequal
+*
+* @example
+* var bool = dlaisnan( NaN, NaN );
+* // returns true
+*
+* @example
+* var bool = dlaisnan( 5.0, 5.0 );
+* // returns false
+*/
+declare function dlaisnan( DIN1: number, DIN2: number ): boolean;
+
+
+// EXPORTS //
+
+export = dlaisnan;

lib/node_modules/@stdlib/lapack/base/dlaisnan/docs/types/test.ts

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+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2026 The Stdlib Authors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+import dlaisnan = require( './index' );
+
+
+// TESTS //
+
+// The function returns a boolean...
+{
+	dlaisnan( 8, 2 ); // $ExpectType boolean
+}
+
+// The compiler throws an error if the function is provided values other than two numbers...
+{
+	dlaisnan( true, 3 ); // $ExpectError
+	dlaisnan( false, 2 ); // $ExpectError
+	dlaisnan( '5', 1 ); // $ExpectError
+	dlaisnan( [], 1 ); // $ExpectError
+	dlaisnan( {}, 2 ); // $ExpectError
+	dlaisnan( ( x: number ): number => x, 2 ); // $ExpectError
+
+	dlaisnan( 9, true ); // $ExpectError
+	dlaisnan( 9, false ); // $ExpectError
+	dlaisnan( 5, '5' ); // $ExpectError
+	dlaisnan( 8, [] ); // $ExpectError
+	dlaisnan( 9, {} ); // $ExpectError
+	dlaisnan( 8, ( x: number ): number => x ); // $ExpectError
+
+	dlaisnan( [], true ); // $ExpectError
+	dlaisnan( {}, false ); // $ExpectError
+	dlaisnan( false, '5' ); // $ExpectError
+	dlaisnan( {}, [] ); // $ExpectError
+	dlaisnan( '5', ( x: number ): number => x ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided insufficient arguments...
+{
+	dlaisnan(); // $ExpectError
+	dlaisnan( 3 ); // $ExpectError
+}