feat: add blas/base/zdscal

PR-URL: stdlib-js#4738 Ref: stdlib-js#2464 Ref: stdlib-js#2039 Co-authored-by: Athan Reines <[email protected]> Reviewed-by: Athan Reines <[email protected]>
Neerajpathak07 · Jan 23, 2025 · 20d210e · 20d210e
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diff --git a/lib/node_modules/@stdlib/blas/base/zdscal/README.md b/lib/node_modules/@stdlib/blas/base/zdscal/README.md
@@ -0,0 +1,233 @@
+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2025 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.
+
+-->
+
+# zdscal
+
+> Scale a double-precision complex floating-point vector by a double-precision floating-point constant.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var zdscal = require( '@stdlib/blas/base/zdscal' );
+```
+
+#### zdscal( N, da, zx, strideZX )
+
+Scales a double-precision complex floating-point vector by a double-precision floating-point constant.
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var real = require( '@stdlib/complex/float64/real' );
+var imag = require( '@stdlib/complex/float64/imag' );
+
+var zx = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
+
+zdscal( 3, 2.0, zx, 1 );
+
+var z = zx.get( 0 );
+// returns <Complex128>
+
+var re = real( z );
+// returns 2.0
+
+var im = imag( z );
+// returns 2.0
+```
+
+The function has the following parameters:
+
+-   **N**: number of indexed elements.
+-   **da**: scalar constant.
+-   **zx**: input [`Complex128Array`][@stdlib/array/complex128].
+-   **strideZX**: stride length for `zx`.
+
+The `N` and stride parameters determine which elements in `zx` are scaled by `da`. For example, to scale every other element in `zx` by `da`,
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var real = require( '@stdlib/complex/float64/real' );
+var imag = require( '@stdlib/complex/float64/imag' );
+
+var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+
+zdscal( 2, 2.0, zx, 2 );
+
+var z = zx.get( 2 );
+// returns <Complex128>
+
+var re = real( z );
+// returns 10.0
+
+var im = imag( z );
+// returns 12.0
+```
+
+Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
+
+<!-- eslint-disable stdlib/capitalized-comments -->
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var real = require( '@stdlib/complex/float64/real' );
+var imag = require( '@stdlib/complex/float64/imag' );
+
+// Initial array:
+var zx0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+
+// Create an offset view:
+var zx1 = new Complex128Array( zx0.buffer, zx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
+
+// Scale every element in `zx1`:
+zdscal( 3, 2.0, zx1, 1 );
+
+var z = zx0.get( 0 );
+// returns <Complex128>
+
+var re = real( z );
+// returns 1.0
+
+var im = imag( z );
+// returns 2.0
+
+z = zx0.get( 1 );
+// returns <Complex128>
+
+re = real( z );
+// returns 6.0
+
+im = imag( z );
+// returns 8.0
+```
+
+#### zdscal.ndarray( N, da, zx, strideZX, offsetZX )
+
+Scales a double-precision complex floating-point vector by a double-precision floating-point constant using alternative indexing semantics.
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var real = require( '@stdlib/complex/float64/real' );
+var imag = require( '@stdlib/complex/float64/imag' );
+
+var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
+
+zdscal.ndarray( 3, 2.0, zx, 1, 0 );
+
+var z = zx.get( 0 );
+// returns <Complex128>
+
+var re = real( z );
+// returns 2.0
+
+var im = imag( z );
+// returns 4.0
+```
+
+The function has the following additional parameters:
+
+-   **offsetZX**: starting index for `zx`.
+
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to scale every other element in the input strided array starting from the second element,
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var real = require( '@stdlib/complex/float64/real' );
+var imag = require( '@stdlib/complex/float64/imag' );
+
+var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+
+zdscal.ndarray( 2, 2.0, zx, 2, 1 );
+
+var z = zx.get( 3 );
+// returns <Complex128>
+
+var re = real( z );
+// returns 14.0
+
+var im = imag( z );
+// returns 16.0
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   If `N <= 0`, both functions return `zx` unchanged.
+-   `zdscal()` corresponds to the [BLAS][blas] level 1 function [`zdscal`][zdscal].
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
+var filledarrayBy = require( '@stdlib/array/filled-by' );
+var Complex128 = require( '@stdlib/complex/float64/ctor' );
+var zdscal = require( '@stdlib/blas/base/zdscal' );
+
+function rand() {
+    return new Complex128( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
+}
+
+var zx = filledarrayBy( 10, 'complex128', rand );
+console.log( zx.toString() );
+
+zdscal( zx.length, 2.0, zx, 1 );
+console.log( zx.toString() );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- 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">
+
+[blas]: http://www.netlib.org/blas
+
+[zdscal]: https://www.netlib.org/lapack/explore-html/d2/de8/group__scal_ga40d50a435a5fcf16cf41fa80d746819f.html#ga40d50a435a5fcf16cf41fa80d746819f
+
+[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
+
+[@stdlib/array/complex128]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/complex128
+
+</section>
+
+<!-- /.links -->
diff --git a/lib/node_modules/@stdlib/blas/base/zdscal/benchmark/benchmark.js b/lib/node_modules/@stdlib/blas/base/zdscal/benchmark/benchmark.js
@@ -0,0 +1,107 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 Complex128Array = require( '@stdlib/array/complex128' );
+var pkg = require( './../package.json' ).name;
+var zdscal = require( './../lib/zdscal.js' );
+
+
+// VARIABLES //
+
+var options = {
+	'dtype': 'float64'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var zxbuf;
+	var zx;
+
+	zxbuf = uniform( len*2, -100.0, 100.0, options );
+	zx = new Complex128Array( zxbuf.buffer );
+
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			zdscal( zx.length, 2.0, zx, 1 );
+			if ( isnan( zxbuf[ i%(len*2) ] ) ) {
+				b.fail( 'should not return NaN' );
+			}
+		}
+		b.toc();
+		if ( isnan( zxbuf[ i%(len*2) ] ) ) {
+			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( pkg+':len='+len, f );
+	}
+}
+
+main();