feat: add ndarray/base/reinterpret-complex128

lib/node_modules/@stdlib/ndarray/base/reinterpret-complex128/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.
+
+-->
+
+# reinterpretComplex128
+
+> Reinterpret a double-precision complex floating-point [ndarray][@stdlib/ndarray/base/ctor] as a real-valued double-precision floating-point [ndarray][@stdlib/ndarray/base/ctor] containing interleaved real and imaginary components.
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var reinterpretComplex128 = require( '@stdlib/ndarray/base/reinterpret-complex128' );
+```
+
+#### reinterpretComplex128( x )
+
+Reinterprets a double-precision complex floating-point [ndarray][@stdlib/ndarray/base/ctor] as a real-valued double-precision floating-point [ndarray][@stdlib/ndarray/base/ctor] containing interleaved real and imaginary components.
+
+```javascript
+var ones = require( '@stdlib/ndarray/base/ones' );
+
+var x = ones( 'complex128', [ 2, 2 ], 'row-major' );
+// returns <ndarray>[ [ <Complex128>[ 1.0, 0.0 ], <Complex128>[ 1.0, 0.0 ] ], [ <Complex128>[ 1.0, 0.0 ], <Complex128>[ 1.0, 0.0 ] ] ]
+
+var out = reinterpretComplex128( x );
+// returns <ndarray>[ [ [ 1.0, 0.0 ], [ 1.0, 0.0 ] ], [ [ 1.0, 0.0 ], [ 1.0, 0.0 ] ] ]
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   The returned [ndarray][@stdlib/ndarray/base/ctor] is a view on the input [ndarray][@stdlib/ndarray/base/ctor] data buffer.
+-   The returned [ndarray][@stdlib/ndarray/base/ctor] has an additional trailing dimension of size two whose elements correspond to the real and imaginary components, respectively, of each complex-valued element in the input [ndarray][@stdlib/ndarray/base/ctor].
+-   The returned [ndarray][@stdlib/ndarray/base/ctor] is a "base" [ndarray][@stdlib/ndarray/base/ctor], and, thus, the returned [ndarray][@stdlib/ndarray/base/ctor] does not perform bounds checking or afford any of the guarantees of the non-base [ndarray][@stdlib/ndarray/ctor] constructor. The primary intent of this function is to reinterpret an ndarray-like object within internal implementations and to do so with minimal overhead.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
+var Complex128Array = require( '@stdlib/array/complex128' );
+var ndarray = require( '@stdlib/ndarray/base/ctor' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var reinterpretComplex128 = require( '@stdlib/ndarray/base/reinterpret-complex128' );
+
+// Create a double-precision complex floating-point ndarray:
+var buf = new Complex128Array( discreteUniform( 8, -5, 5 ) );
+var x = ndarray( 'complex128', buf, [ 2, 2 ], [ 2, 1 ], 0, 'row-major' );
+
+// Reinterpret as a double-precision floating-point ndarray:
+var out = reinterpretComplex128( x );
+console.log( ndarray2array( out ) );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<section class="references">
+
+</section>
+
+<!-- /.references -->
+
+<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
+
+<section class="related">
+
+</section>
+
+<!-- /.related -->
+
+<section class="links">
+
+[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/ctor
+
+[@stdlib/ndarray/base/ctor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/base/ctor
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/ndarray/base/reinterpret-complex128/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 Complex128Array = require( '@stdlib/array/complex128' );
+var ndarrayBase = require( '@stdlib/ndarray/base/ctor' );
+var ndarray = require( '@stdlib/ndarray/ctor' );
+var isndarrayLike = require( '@stdlib/assert/is-ndarray-like' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var reinterpretComplex128 = require( './../lib' );
+
+
+// MAIN //
+
+bench( format( '%s::base_ndarray,2d', pkg ), function benchmark( b ) {
+	var strides;
+	var values;
+	var buffer;
+	var offset;
+	var dtype;
+	var shape;
+	var order;
+	var out;
+	var i;
+
+	dtype = 'complex128';
+	buffer = new Complex128Array( 4 );
+	shape = [ 2, 2 ];
+	strides = [ 2, 1 ];
+	offset = 0;
+	order = 'row-major';
+
+	values = [
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order ),
+		ndarrayBase( dtype, buffer, shape, strides, offset, order )
+	];
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = reinterpretComplex128( values[ i%values.length ] );
+		if ( typeof out !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isndarrayLike( out ) ) {
+		b.fail( 'should return an ndarray' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( format( '%s::ndarray,2d', pkg ), function benchmark( b ) {
+	var strides;
+	var values;
+	var buffer;
+	var offset;
+	var dtype;
+	var shape;
+	var order;
+	var out;
+	var i;
+
+	dtype = 'complex128';
+	buffer = new Complex128Array( 4 );
+	shape = [ 2, 2 ];
+	strides = [ 2, 1 ];
+	offset = 0;
+	order = 'row-major';
+
+	values = [
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order ),
+		ndarray( dtype, buffer, shape, strides, offset, order )
+	];
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		out = reinterpretComplex128( values[ i%values.length ] );
+		if ( typeof out !== 'object' ) {
+			b.fail( 'should return an object' );
+		}
+	}
+	b.toc();
+	if ( !isndarrayLike( out ) ) {
+		b.fail( 'should return an ndarray' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/ndarray/base/reinterpret-complex128/docs/repl.txt

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+
+{{alias}}( x )
+    Reinterprets a double-precision complex floating-point ndarray as a real-
+    valued double-precision floating-point ndarray containing interleaved real
+    and imaginary components.
+
+    The returned ndarray is a view on the input ndarray data buffer.
+
+    The returned ndarray has an additional trailing dimension of size two whose
+    elements correspond to the real and imaginary components, respectively, of
+    each complex-valued element in the input ndarray.
+
+    The returned ndarray is a "base" ndarray, and, thus, the returned ndarray
+    does not perform bounds checking or afford any of the guarantees of the
+    non-base ndarray constructor. The primary intent of this function is to
+    reinterpret an ndarray-like object within internal implementations and to
+    do so with minimal overhead.
+
+    Parameters
+    ----------
+    x: ndarray
+        Input ndarray.
+
+    Returns
+    -------
+    out: ndarray
+        Double-precision floating-point ndarray view.
+
+    Examples
+    --------
+    > var dt = 'complex128';
+    > var x = {{alias:@stdlib/ndarray/base/zeros}}( dt, [ 2, 2 ], 'row-major' );
+    > var out = {{alias}}( x )
+    <ndarray>[ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ], [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ]
+
+    See Also
+    --------
+

lib/node_modules/@stdlib/ndarray/base/reinterpret-complex128/docs/types/index.d.ts

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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.
+*/
+
+// TypeScript Version: 4.1
+
+/// <reference types="@stdlib/types"/>
+
+import { complex128ndarray, float64ndarray } from '@stdlib/types/ndarray';
+
+/**
+* Reinterprets a double-precision complex floating-point ndarray as a real-valued double-precision floating-point ndarray containing interleaved real and imaginary components.
+*
+* ## Notes
+*
+* -   The returned ndarray is a view on the input ndarray data buffer.
+* -   The returned ndarray has an additional trailing dimension of size two whose elements correspond to the real and imaginary components, respectively, of each complex-valued element in the input ndarray.
+* -   The returned ndarray is a "base" ndarray, and, thus, the returned ndarray does not perform bounds checking or afford any of the guarantees of the non-base ndarray constructor. The primary intent of this function is to reinterpret an ndarray-like object within internal implementations and to do so with minimal overhead.
+*
+* @param x - input ndarray
+* @returns double-precision floating-point ndarray view
+*
+* @example
+* var ones = require( '@stdlib/ndarray/base/ones' );
+*
+* var x = ones( 'complex128', [ 2, 2 ], 'row-major' );
+* // returns <ndarray>[ [ <Complex128>[ 1.0, 0.0 ], <Complex128>[ 1.0, 0.0 ] ], [ <Complex128>[ 1.0, 0.0 ], <Complex128>[ 1.0, 0.0 ] ] ]
+*
+* var out = reinterpretComplex128( x );
+* // returns <ndarray>[ [ [ 1.0, 0.0 ], [ 1.0, 0.0 ] ], [ [ 1.0, 0.0 ], [ 1.0, 0.0 ] ] ]
+*/
+declare function reinterpretComplex128( x: complex128ndarray ): float64ndarray;
+
+
+// EXPORTS //
+
+export = reinterpretComplex128;

lib/node_modules/@stdlib/ndarray/base/reinterpret-complex128/docs/types/test.ts

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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.
+*/
+
+import zeros = require( '@stdlib/ndarray/base/zeros' );
+import reinterpretComplex128 = require( './index' );
+
+
+// TESTS //
+
+// The function returns a float64ndarray...
+{
+	const x = zeros( 'complex128', [ 2, 2 ], 'row-major' );
+
+	reinterpretComplex128( x ); // $ExpectType float64ndarray
+}
+
+// The compiler throws an error if the function is not provided a first argument which is a complex128ndarray...
+{
+	reinterpretComplex128( '5' ); // $ExpectError
+	reinterpretComplex128( 5 ); // $ExpectError
+	reinterpretComplex128( true ); // $ExpectError
+	reinterpretComplex128( false ); // $ExpectError
+	reinterpretComplex128( null ); // $ExpectError
+	reinterpretComplex128( {} ); // $ExpectError
+	reinterpretComplex128( [ '5' ] ); // $ExpectError
+	reinterpretComplex128( ( x: number ): number => x ); // $ExpectError
+	reinterpretComplex128( zeros( 'float64', [ 2, 2 ], 'row-major' ) ); // $ExpectError
+	reinterpretComplex128( zeros( 'float32', [ 2, 2 ], 'row-major' ) ); // $ExpectError
+	reinterpretComplex128( zeros( 'int32', [ 2, 2 ], 'row-major' ) ); // $ExpectError
+	reinterpretComplex128( zeros( 'complex64', [ 2, 2 ], 'row-major' ) ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided an unsupported number of arguments...
+{
+	const x = zeros( 'complex128', [ 2, 2 ], 'row-major' );
+
+	reinterpretComplex128(); // $ExpectError
+	reinterpretComplex128( x, {} ); // $ExpectError
+}