feat: add lapack/base/dgetrf

lib/node_modules/@stdlib/lapack/base/dgetrf/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.
+
+-->
+
+# dgetrf
+
+> Compute an `LU` factorization of a real general matrix `A` using elimination with partial pivoting and row interchanges.
+
+<section class="intro">
+
+The `dgetrf` routine computes an LU factorization of a real `M`-by-`N` matrix `A`. The factorization has the form
+
+```math
+A = P * L * U
+```
+
+where `P` is a permutation matrix, `L` is lower triangular or trapezoidal with unit diagonal elements, and `U` is upper triangular or trapezoidal. The routine supports square, tall, and wide matrices.
+
+The factors are stored in-place in `A`: the strictly lower triangular part contains the multipliers defining `L`, and the upper triangular part contains `U`. The unit diagonal elements of `L` are not stored. The vector `IPIV` records the row interchanges used during factorization.
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var dgetrf = require( '@stdlib/lapack/base/dgetrf' );
+```
+
+#### dgetrf( M, N, A, LDA, IPIV )
+
+Computes an LU factorization of a real general `M`-by-`N` matrix `A` using partial pivoting.
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var Int32Array = require( '@stdlib/array/int32' );
+
+var A = new Float64Array( [
+    1.0, 3.0, 2.0,
+    2.0, 4.0, 1.0,
+    1.0, 2.0, 3.0
+] );
+var IPIV = new Int32Array( 3 );
+
+var info = dgetrf( 3, 3, A, 3, IPIV );
+// info => 0
+// IPIV => <Int32Array>[ 1, 2, 2 ]
+```
+
+The function has the following parameters:
+
+-   **M**: number of rows in `A`.
+-   **N**: number of columns in `A`.
+-   **A**: input matrix as a [`Float64Array`][mdn-float64array], stored in column-major order. `A` is overwritten by the factors.
+-   **LDA**: stride between successive columns of `A`. `LDA` must be at least `max(1,M)`.
+-   **IPIV**: pivot indices as an [`Int32Array`][mdn-int32array]. For each `i` in `0 <= i < min(M,N)`, row `i` is interchanged with row `IPIV(i)`.
+
+Indexing is relative to the first element. To introduce a byte offset for the public API, use typed array views.
+
+#### dgetrf.ndarray
+
+`dgetrf.ndarray( M, N, A, strideA1, strideA2, offsetA, IPIV, strideIPIV, offsetIPIV )`
+
+Computes an LU factorization using alternative indexing semantics.
+
+```javascript
+var A = new Float64Array( [
+    1.0, 3.0, 2.0,
+    2.0, 4.0, 1.0,
+    1.0, 2.0, 3.0
+] );
+var IPIV = new Int32Array( 3 );
+
+var info = dgetrf.ndarray( 3, 3, A, 1, 3, 0, IPIV, 1, 0 );
+// info => 0
+```
+
+The function has the following additional parameters:
+
+-   **strideA1**: stride of the first dimension of `A`.
+-   **strideA2**: stride of the second dimension of `A`.
+-   **offsetA**: starting index for `A`.
+-   **strideIPIV**: stride length for `IPIV`.
+-   **offsetIPIV**: starting index for `IPIV`.
+
+While typed array views mandate a view offset based on the underlying buffer, ndarray offsets support indexing semantics based on starting indices. Strides may be positive or negative.
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   Both functions mutate `A` and `IPIV`.
+-   If `INFO` is zero, the factorization was successful. If `INFO` is greater than zero, `U(INFO,INFO)` is exactly zero; the factorization has been completed, but `U` is singular.
+-   The pivot indices use zero-based JavaScript indexing. This differs from the one-based pivot indices in the original Fortran LAPACK interface.
+-   The routine computes the factorization in-place and returns the status code rather than separate `L` and `U` matrices.
+-   `dgetrf()` corresponds to the [LAPACK][lapack] routine [`DGETRF`][lapack-dgetrf].
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+```javascript
+var dgetrf = require( '@stdlib/lapack/base/dgetrf' );
+var Float64Array = require( '@stdlib/array/float64' );
+var Int32Array = require( '@stdlib/array/int32' );
+
+var A = new Float64Array( [
+    4.0, 2.0, 1.0,
+    1.0, 3.0, 2.0
+] );
+var IPIV = new Int32Array( 2 );
+
+// Factor a 3-by-2 matrix stored in column-major order:
+var info = dgetrf( 3, 2, A, 3, IPIV );
+console.log( A );
+console.log( IPIV );
+console.log( info );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<section class="links">
+
+[lapack]: https://www.netlib.org/lapack/explore-html/
+
+[lapack-dgetrf]: https://www.netlib.org/lapack/double/dgetrf.f
+
+[mdn-float64array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Float64Array
+
+[mdn-int32array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Int32Array
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/lapack/base/dgetrf/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 uniform = require( '@stdlib/random/array/uniform' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var Int32Array = require( '@stdlib/array/int32' );
+var Float64Array = require( '@stdlib/array/float64' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var dgetrf = require( './../lib/dgetrf.js' );
+
+
+// VARIABLES //
+
+var options = {
+	'dtype': 'float64'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - matrix dimension
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var A = uniform( len*len, -1.0, 1.0, options );
+	var IPIV = new Int32Array( len );
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var info;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			info = dgetrf( len, len, A, len, IPIV );
+			if ( info < 0 ) {
+				b.fail( 'should return a valid status code' );
+			}
+		}
+		b.toc();
+		if ( info < 0 ) {
+			b.fail( 'should return a valid status code' );
+		}
+		b.pass( 'benchmark finished' );
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+function main() {
+	var len;
+	var min;
+	var max;
+	var f;
+	var i;
+
+	min = 1;
+	max = 3;
+	for ( i = min; i <= max; i++ ) {
+		len = pow( 10, i );
+		f = createBenchmark( len );
+		bench( format( '%s:len=%d', pkg, len ), f );
+	}
+}
+
+main();

lib/node_modules/@stdlib/lapack/base/dgetrf/benchmark/benchmark.ndarray.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 uniform = require( '@stdlib/random/array/uniform' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var Int32Array = require( '@stdlib/array/int32' );
+var Float64Array = require( '@stdlib/array/float64' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var dgetrf = require( './../lib/ndarray.js' );
+
+
+// VARIABLES //
+
+var options = {
+	'dtype': 'float64'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - matrix dimension
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var A = uniform( len*len, -1.0, 1.0, options );
+	var IPIV = new Int32Array( len );
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var info;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			info = dgetrf( len, len, A, 1, len, 0, IPIV, 1, 0 );
+			if ( info < 0 ) {
+				b.fail( 'should return a valid status code' );
+			}
+		}
+		b.toc();
+		if ( info < 0 ) {
+			b.fail( 'should return a valid status code' );
+		}
+		b.pass( 'benchmark finished' );
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+function main() {
+	var len;
+	var min;
+	var max;
+	var f;
+	var i;
+
+	min = 1;
+	max = 3;
+	for ( i = min; i <= max; i++ ) {
+		len = pow( 10, i );
+		f = createBenchmark( len );
+		bench( format( '%s:ndarray:len=%d', pkg, len ), f );
+	}
+}
+
+main();