feat: add blas/base/zscal

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

@@ -0,0 +1,242 @@
+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2024 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.
+
+-->
+
+# zscal
+
+> Scales a double-precision complex floating-point vector by a double-precision complex floating-point constant.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var zscal = require( '@stdlib/blas/base/zscal' );
+```
+
+#### zscal( N, za, zx, strideX )
+
+Scales values from `zx` by `za`.
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var Complex128 = require( '@stdlib/complex/float64' );
+var real = require( '@stdlib/complex/real' );
+var imag = require( '@stdlib/complex/imag' );
+
+var zx = new Complex128Array( [ 1.0, 1.0, 1.0, 1.0, 1.0, 1.0 ] );
+var za = new Complex128( 2.0, 0.0 );
+
+zscal( 3, za, 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.
+-   **za**: scalar [`Complex128`][@stdlib/complex/float64] constant. 
+-   **zx**: input [`Complex128Array`][@stdlib/array/complex128].
+-   **strideX**: index increment for `zx`.
+
+The `N` and stride parameters determine how values from `zx` are scaled by `za`. For example, to scale every other value in `zx` by `za`,
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var Complex128 = require( '@stdlib/complex/float64' );
+var real = require( '@stdlib/complex/real' );
+var imag = require( '@stdlib/complex/imag' );
+
+var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+var za = new Complex128( 2.0, 0.0 );
+
+zscal( 2, za, 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 Complex128 = require( '@stdlib/complex/float64' );
+var real = require( '@stdlib/complex/real' );
+var imag = require( '@stdlib/complex/imag' );
+
+// Initial array:
+var zx0 = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+
+// Define a scalar constant:
+var za = new Complex128( 2.0, 2.0 );
+
+// Create an offset view:
+var zx1 = new Complex128Array( zx0.buffer, zx0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
+
+// Scales every other value from `zx1` by `za`...
+zscal( 3, za, zx1, 1 );
+
+var z = zx0.get( 1 );
+// returns <Complex128>
+
+var re = real( z );
+// returns -2.0
+
+var im = imag( z );
+// returns 14.0
+```
+
+#### zscal.ndarray( N, za, zx, strideX, offsetX )
+
+Scales values from `zx` by `za` using alternative indexing semantics.
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var Complex128 = require( '@stdlib/complex/float64' );
+var real = require( '@stdlib/complex/real' );
+var imag = require( '@stdlib/complex/imag' );
+
+var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
+var za = new Complex128( 2.0, 2.0 );
+
+zscal.ndarray( 3, za, zx, 1, 0 );
+
+var z = zx.get( 0 );
+// returns <Complex128>
+
+var re = real( z );
+// returns -2.0
+
+var im = imag( z );
+// returns 6.0
+```
+
+The function has the following additional parameters:
+
+-   **offsetX**: 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 value in the input strided array starting from the second element,
+
+```javascript
+var Complex128Array = require( '@stdlib/array/complex128' );
+var Complex128 = require( '@stdlib/complex/float64' );
+var real = require( '@stdlib/complex/real' );
+var imag = require( '@stdlib/complex/imag' );
+
+var zx = new Complex128Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );
+var za = new Complex128( 2.0, 2.0 );
+
+zscal.ndarray( 2, za, zx, 2, 1 );
+
+var z = zx.get( 3 );
+// returns <Complex128>
+
+var re = real( z );
+// returns -2.0
+
+var im = imag( z );
+// returns 30.0
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   If `N <= 0` or `strideX <= 0` , both functions return `zx` unchanged.
+-   `zscal()` corresponds to the [BLAS][blas] level 1 function [`zscal`][zscal].
+
+</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' );
+var zscal = require( '@stdlib/blas/base/zscal' );
+
+function rand() {
+    return new Complex128( discreteUniform( 0, 10 ), discreteUniform( -5, 5 ) );
+}
+
+var zx = filledarrayBy( 10, 'complex128', rand );
+console.log( zx.toString() );
+
+var za = new Complex128( 2.0, 2.0 );
+console.log( za.toString() );
+
+// Scales elements from `zx` by `za`:
+zscal( zx.length, za, zx, 1 );
+console.log( zx.get( zx.length-1 ).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
+
+[zscal]: http://www.netlib.org/lapack/explore-html/da/df6/group__complex__blas__level1.html
+
+[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
+
+[@stdlib/complex/float64]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/complex/float64
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/blas/base/zscal/benchmark/benchmark.js

@@ -0,0 +1,114 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 Complex128 = require( '@stdlib/complex/float64' );
+var reinterpret = require('@stdlib/strided/base/reinterpret-complex128');
+var pkg = require( './../package.json' ).name;
+var zscal = require( './../lib/zscal.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 viewX;
+	var za;
+	var zx;
+
+	zx = uniform( len*2, -100.0, 100.0, options );
+	zx = new Complex128Array( zx.buffer );
+
+	viewX = reinterpret( zx, 0 );
+
+	za = new Complex128( 1.0, 0.0 );
+
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			zscal( zx.length, za, zx, 1 );
+			if ( isnan( viewX[ i%(len*2) ] ) ) {
+				b.fail( 'should not return NaN' );
+			}
+		}
+		b.toc();
+		if ( isnan( viewX[ 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();