feat: add C and Fortran implementation of blas/base/drotg

lib/node_modules/@stdlib/blas/base/drotg/README.md

@@ -2,7 +2,7 @@
 
 @license Apache-2.0
 
-Copyright (c) 2023 The Stdlib Authors.
+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.
@@ -76,6 +76,8 @@ var bool = ( y === out );
 
 <section class="examples">
 
+## Examples
+
 ```javascript
 var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
 var drotg = require( '@stdlib/blas/base/drotg' );
@@ -93,6 +95,135 @@ for ( i = 0; i < 100; i++ ) {
 
 <!-- /.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
+#include "stdlib/blas/base/drotg.h"
+```
+
+#### c_drotg( a, b, \*Out, strideOut )
+
+Constructs a Givens plane rotation provided two double-precision floating-point values `a` and `b`.
+
+```c
+double Out[ 4 ];
+c_drotg( 0.0, 2.0, Out, 1 );
+// Out => [ 2.0, 1.0, 0.0, 1.0 ]
+```
+
+The function accepts the following arguments:
+
+-   **a**: `[in] double` rotational elimination parameter.
+-   **b**: `[in] double` rotational elimination parameter.
+-   **Out**: `[out] double*` output array.
+-   **strideOut**: `[in] CBLAS_INT` stride length for `Out`.
+
+```c
+void c_drotg( const double a, const double b, double *Out, const CBLAS_INT strideOut );
+```
+
+#### c_drotg_assign( a, b, \*Out, strideOut, offsetOut )
+
+Constructs a Givens plane rotation provided two double-precision floating-point values `a` and `b` using alternative indexing semantics.
+
+```c
+double Out[ 4 ];
+c_drotg_assign( 0.0, 2.0, Out, 1, 0 );
+// Out => [ 2.0, 1.0, 0.0, 1.0 ]
+```
+
+The function accepts the following arguments:
+
+-   **a**: `[in] double` rotational elimination parameter.
+-   **b**: `[in] double` rotational elimination parameter.
+-   **Out**: `[out] double*` output array.
+-   **strideOut**: `[in] CBLAS_INT` stride length for `Out`.
+-   **offsetOut**: `[in] CBLAS_INT` starting index for `Out`.
+
+```c
+void c_drotg_assign( const double a, const double b, double *Out, const CBLAS_INT strideOut, const CBLAS_INT offsetOut );
+```
+
+</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
+#include "stdlib/blas/base/drotg.h"
+#include <stdio.h>
+
+int main( void ) {
+    // Specify rotational elimination parameters:
+    const double a = 0.0;
+    const double b = 2.0;
+    int i;
+
+    // Create strided arrays:
+    double Out[ 4 ];
+
+    // Specify stride lengths:
+    const int strideOut = 1;
+
+    // Apply plane rotation:
+    c_drotg( a, b, Out, strideOut );
+
+    // Print the result:
+    for ( i = 0; i < 4; i++ ) {
+        printf( "Out[%d] = %lf\n", i, Out[ i ] );
+    }
+
+    // Apply plane rotation using alternative indexing semantics:
+    c_drotg_assign( a, b, Out, strideOut, 0 );
+
+    // Print the result:
+    for ( i = 0; i < 4; i++ ) {
+        printf( "Out[%d] = %lf\n", i, Out[ i ] );
+    }
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
 <!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
 
 <section class="related">

lib/node_modules/@stdlib/blas/base/drotg/benchmark/benchmark.assign.js

@@ -0,0 +1,108 @@
+/**
+* @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 isnanf = require( '@stdlib/math/base/assert/is-nanf' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var format = require( '@stdlib/string/format' );
+var Float64Array = require( '@stdlib/array/float64' );
+var pkg = require( './../package.json' ).name;
+var drotg = require( './../lib/assign.js' );
+
+
+// VARIABLES //
+
+var options = {
+	'dtype': 'float32'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark(len) {
+	var va = uniform(len, -100.0, 100.0, options);
+	var vb = uniform(len, -100.0, 100.0, options);
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark(b) {
+		var out;
+		var z;
+		var i;
+
+		out = new Float64Array(4);
+
+		b.tic();
+		for (i = 0; i < b.iterations; i++) {
+			z = drotg(va[i % len], vb[i % len], out, 1, 0);
+			if (isnanf(z[i % 4])) {
+				b.fail('should not return NaN');
+			}
+		}
+		b.toc();
+		if (isnanf(z[i % 4])) {
+			b.fail('should not return NaN');
+		}
+		b.pass('benchmark finished');
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+	var len;
+	var min;
+	var max;
+	var f;
+	var i;
+
+	min = 1; // 10^min
+	max = 6; // 10^max
+
+	for (i = min; i <= max; i++) {
+		len = pow(10, i);
+		f = createBenchmark(len);
+		bench(format('%s:assign:len=%d', pkg, len), f);
+	}
+}
+
+main();

lib/node_modules/@stdlib/blas/base/drotg/benchmark/benchmark.assign.native.js

@@ -0,0 +1,113 @@
+/**
+* @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 resolve = require( 'path' ).resolve;
+var bench = require( '@stdlib/bench' );
+var uniform = require( '@stdlib/random/array/uniform' );
+var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var format = require( '@stdlib/string/format' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var Float64Array = require( '@stdlib/array/float64' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var drotg = tryRequire(resolve(__dirname, './../lib/assign.native.js'));
+var opts = {
+	'skip': (drotg instanceof Error)
+};
+var options = {
+	'dtype': 'float32'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark(len) {
+	var va = uniform(len, -100.0, 100.0, options);
+	var vb = uniform(len, -100.0, 100.0, options);
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark(b) {
+		var out;
+		var z;
+		var i;
+
+		out = new Float64Array(4);
+
+		b.tic();
+		for (i = 0; i < b.iterations; i++) {
+			z = drotg(va[i % len], vb[i % len], out, 1, 0);
+			if (isnanf(z[i % 4])) {
+				b.fail('should not return NaN');
+			}
+		}
+		b.toc();
+		if (isnanf(z[i % 4])) {
+			b.fail('should not return NaN');
+		}
+		b.pass('benchmark finished');
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+	var len;
+	var min;
+	var max;
+	var f;
+	var i;
+
+	min = 1; // 10^min
+	max = 6; // 10^max
+
+	for (i = min; i <= max; i++) {
+		len = pow(10, i);
+		f = createBenchmark(len);
+		bench(format('%s::native:len=%d', pkg, len), opts, f);
+	}
+}
+
+main();