feat: add lapack/base/dgeequ

lib/node_modules/@stdlib/lapack/base/dgeequ/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.
+
+-->
+
+# dgeequ
+
+> Compute row and column scaling factors intended to equilibrate an M-by-N real matrix `A` and reduce its condition number.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var dgeequ = require( '@stdlib/lapack/base/dgeequ' );
+```
+
+#### dgeequ( order, M, N, A, LDA, R, C )
+
+Computes row and column scaling factors intended to equilibrate an M-by-N real matrix `A` and reduce its condition number.
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+var A = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0 ] );
+var R = new Float64Array( 3 );
+var C = new Float64Array( 3 );
+
+var out = dgeequ( 'row-major', 3, 3, A, 3, R, C );
+// returns [ 0.3333333333333333, 0.7777777777777777, 9.0, 0 ]
+```
+
+The function has the following parameters:
+
+-   **order**: storage layout (either `'row-major'` or `'column-major'`).
+-   **M**: number of rows of matrix `A`.
+-   **N**: number of columns of matrix `A`.
+-   **A**: the M-by-N matrix `A` as a [`Float64Array`][mdn-float64array].
+-   **LDA**: leading dimension of matrix `A`.
+-   **R**: output row scale factors as a [`Float64Array`][mdn-float64array].
+-   **C**: output column scale factors as a [`Float64Array`][mdn-float64array].
+
+The function returns a `Collection` containing:
+
+-   **rowcnd**: ratio of the smallest `R[i]` to the largest `R[i]`.
+-   **colcnd**: ratio of the smallest `C[j]` to the largest `C[j]`.
+-   **amax**: absolute value of the largest matrix element.
+-   **info**: status code. If `0`, successful exit. If `> 0` and `<= M`, the `i`-th row is exactly zero (where `i` equals the status code); if `> M`, the `(i-M)`-th column is exactly zero. Note that the status code uses one-based indexing to match the LAPACK convention, so the corresponding zero-based JavaScript index is `info - 1`.
+
+Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
+
+#### dgeequ.ndarray( M, N, A, sa1, sa2, oa, R, sr, or, C, sc, oc )
+
+Computes row and column scaling factors intended to equilibrate an M-by-N real matrix `A` and reduce its condition number using alternative indexing semantics.
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+var A = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0 ] );
+var R = new Float64Array( 3 );
+var C = new Float64Array( 3 );
+
+var out = dgeequ.ndarray( 3, 3, A, 3, 1, 0, R, 1, 0, C, 1, 0 );
+// returns [ 0.3333333333333333, 0.7777777777777777, 9.0, 0 ]
+```
+
+The function has the following additional parameters:
+
+-   **sa1**: stride of the first dimension of `A`.
+-   **sa2**: stride of the second dimension of `A`.
+-   **oa**: starting index for `A`.
+-   **sr**: stride length for `R`.
+-   **or**: starting index for `R`.
+-   **sc**: stride length for `C`.
+-   **oc**: starting index for `C`.
+
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameters support indexing semantics based on starting indices.
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   Both functions mutate the output arrays `R` and `C`.
+-   `dgeequ()` corresponds to the [LAPACK][LAPACK] routine [`dgeequ`][lapack-dgeequ].
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var dgeequ = require( '@stdlib/lapack/base/dgeequ' );
+
+var A = new Float64Array( [ 1.0, 10.0, 100.0, 1000.0 ] );
+var R = new Float64Array( 2 );
+var C = new Float64Array( 2 );
+
+var out = dgeequ( 'row-major', 2, 2, A, 2, R, C );
+console.log( R );
+// => <Float64Array>[ 0.1, 0.001 ]
+
+console.log( C );
+// => <Float64Array>[ 10.0, 1.0 ]
+
+console.log( out );
+// => [ 0.01, 0.1, 1000.0, 0 ]
+```
+
+</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-dgeequ]: https://netlib.org/lapack/explore-html/d5/d8a/group__geequ_ga7238812c5c26fc2fbe8bbbc22b6ee885.html#ga7238812c5c26fc2fbe8bbbc22b6ee885
+
+[mdn-float64array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array
+
+[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
+
+</section>
+
+<!-- /.links -->

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

@@ -0,0 +1,121 @@
+/**
+* @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 uniform = require( '@stdlib/random/array/uniform' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var floor = require( '@stdlib/math/base/special/floor' );
+var format = require( '@stdlib/string/format' );
+var Float64Array = require( '@stdlib/array/float64' );
+var pkg = require( './../package.json' ).name;
+var dgeequ = require( './../lib/dgeequ.js' );
+
+
+// VARIABLES //
+
+var LAYOUTS = [
+	'row-major',
+	'column-major'
+];
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {string} order - storage layout
+* @param {PositiveInteger} N - number of elements along each dimension
+* @returns {Function} benchmark function
+*/
+function createBenchmark( order, N ) {
+	var A;
+	var R;
+	var C;
+
+	A = uniform( N*N, -10.0, 10.0, {
+		'dtype': 'float64'
+	});
+	R = new Float64Array( N );
+	C = new Float64Array( N );
+
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var out;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			out = dgeequ( order, N, N, A, N, R, C );
+			if ( isnan( out[ 0 ] ) ) {
+				b.fail( 'should not return NaN' );
+			}
+		}
+		b.toc();
+		if ( isnan( out[ 0 ] ) ) {
+			b.fail( 'should not return NaN' );
+		}
+		b.pass( 'benchmark finished' );
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+	var min;
+	var max;
+	var ord;
+	var N;
+	var f;
+	var i;
+	var k;
+
+	min = 1; // 10^min
+	max = 6; // 10^max
+
+	for ( k = 0; k < LAYOUTS.length; k++ ) {
+		ord = LAYOUTS[ k ];
+		for ( i = min; i <= max; i++ ) {
+			N = floor( pow( pow( 10, i ), 1.0/2.0 ) );
+			f = createBenchmark( ord, N );
+			bench( format( '%s::equidimensional:order=%s,size=%d', pkg, ord, N*N ), f );
+		}
+	}
+}
+
+main();