From 12c8edae633b9a961cae420ae71fb3f0e66f6efb Mon Sep 17 00:00:00 2001
From: headlessNode <harriskhan047@outlook.com>
Date: Thu, 24 Sep 2026 14:58:25 +0500
Subject: [PATCH 1/2] feat: add blas/ext/base/ndarray/dwhere

---
 .../blas/ext/base/ndarray/dwhere/README.md    | 128 ++++++
 .../ndarray/dwhere/benchmark/benchmark.js     | 110 +++++
 .../ext/base/ndarray/dwhere/docs/repl.txt     |  32 ++
 .../base/ndarray/dwhere/docs/types/index.d.ts |  57 +++
 .../base/ndarray/dwhere/docs/types/test.ts    |  72 +++
 .../ext/base/ndarray/dwhere/examples/index.js |  46 ++
 .../blas/ext/base/ndarray/dwhere/lib/index.js |  47 ++
 .../blas/ext/base/ndarray/dwhere/lib/main.js  |  76 ++++
 .../blas/ext/base/ndarray/dwhere/package.json |  73 ++++
 .../blas/ext/base/ndarray/dwhere/test/test.js | 412 ++++++++++++++++++
 10 files changed, 1053 insertions(+)
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/README.md
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/repl.txt
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/index.d.ts
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/test.ts
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/examples/index.js
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/index.js
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/main.js
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/package.json
 create mode 100644 lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/test/test.js

diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/README.md b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/README.md
new file mode 100644
index 000000000000..96ed983e7c71
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/README.md
@@ -0,0 +1,128 @@
+<!--
+
+@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.
+
+-->
+
+# dwhere
+
+> Take elements from one of two one-dimensional double-precision floating-point ndarrays depending on a condition.
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var dwhere = require( '@stdlib/blas/ext/base/ndarray/dwhere' );
+```
+
+#### dwhere( arrays )
+
+Takes elements from one of two one-dimensional double-precision floating-point ndarrays depending on a condition.
+
+```javascript
+var BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
+
+var condition = new BooleanVector( [ true, false, true, false, true ] );
+var x = new Float64Vector( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+var y = new Float64Vector( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+var out = new Float64Vector( 5 );
+
+dwhere( [ condition, x, y, out ] );
+// out => <ndarray>[ 1.0, 7.0, 3.0, 9.0, 5.0 ]
+```
+
+The function has the following parameters:
+
+-   **arrays**: array-like object containing the following ndarrays:
+
+    -   a one-dimensional condition ndarray.
+    -   first one-dimensional input ndarray.
+    -   second one-dimensional input ndarray.
+    -   a one-dimensional output ndarray.
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var bernoulli = require( '@stdlib/random/array/bernoulli' );
+var discreteUniform = require( '@stdlib/random/discrete-uniform' );
+var BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var dwhere = require( '@stdlib/blas/ext/base/ndarray/dwhere' );
+
+var opts = {
+    'dtype': 'float64'
+};
+
+var cbuf = bernoulli( 10, 0.5, {
+    'dtype': 'uint8'
+});
+var condition = new BooleanVector( cbuf.buffer );
+console.log( ndarray2array( condition ) );
+
+var x = discreteUniform( [ 10 ], -100, 100, opts );
+console.log( ndarray2array( x ) );
+
+var y = discreteUniform( [ 10 ], -100, 100, opts );
+console.log( ndarray2array( y ) );
+
+var out = discreteUniform( [ 10 ], -100, 100, opts );
+
+dwhere( [ condition, x, y, out ] );
+console.log( ndarray2array( out ) );
+```
+
+</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">
+
+</section>
+
+<!-- /.links -->
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js
new file mode 100644
index 000000000000..0ba72635518c
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js
@@ -0,0 +1,110 @@
+/**
+* @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 bernoulli = require( '@stdlib/random/array/bernoulli' );
+var uniform = require( '@stdlib/random/uniform' );
+var BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var dwhere = require( './../lib' );
+
+
+// VARIABLES //
+
+var options = {
+	'dtype': 'float64'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - ndarray length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var cbuf = bernoulli( len, 0.5, {
+		'dtype': 'uint8'
+	});
+	var condition = new BooleanVector( cbuf.buffer );
+	var out = uniform( [ len ], -100.0, 100.0, options );
+	var x = uniform( [ len ], -100.0, 100.0, options );
+	var y = uniform( [ len ], -100.0, 100.0, options );
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var v;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			v = dwhere( [ condition, x, y, out ] );
+			if ( typeof v !== 'object' ) {
+				b.fail( 'should return an ndarray' );
+			}
+		}
+		b.toc();
+		if ( typeof v !== 'object' ) {
+			b.fail( 'should return an ndarray' );
+		}
+		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:len=%d', pkg, len ), f );
+	}
+}
+
+main();
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/repl.txt b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/repl.txt
new file mode 100644
index 000000000000..4c5d6d2ab42a
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/repl.txt
@@ -0,0 +1,32 @@
+
+{{alias}}( arrays )
+    Takes elements from one of two one-dimensional double-precision floating-
+    point ndarrays depending on a condition.
+
+    Parameters
+    ----------
+    arrays: ArrayLikeObject<ndarray>
+        Array-like object containing the following ndarrays:
+
+        - a one-dimensional condition ndarray.
+        - first one-dimensional input ndarray.
+        - second one-dimensional input ndarray.
+        - a one-dimensional output ndarray.
+
+    Returns
+    -------
+    out: ndarray
+        Output ndarray.
+
+    Examples
+    --------
+    > var c = new {{alias:@stdlib/ndarray/vector/bool}}( [ true, false, true, false ] );
+    > var x = new {{alias:@stdlib/ndarray/vector/float64}}( [ 1.0, 2.0, 3.0, 4.0 ] );
+    > var y = new {{alias:@stdlib/ndarray/vector/float64}}( [ 5.0, 6.0, 7.0, 8.0 ] );
+    > var out = new {{alias:@stdlib/ndarray/vector/float64}}( 4 );
+    > {{alias}}( [ c, x, y, out ] )
+    <ndarray>[ 1.0, 6.0, 3.0, 8.0 ]
+
+    See Also
+    --------
+
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/index.d.ts b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/index.d.ts
new file mode 100644
index 000000000000..4ab9c4657f33
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/index.d.ts
@@ -0,0 +1,57 @@
+/*
+* @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 { float64ndarray, boolndarray } from '@stdlib/types/ndarray';
+
+/**
+* Takes elements from one of two one-dimensional double-precision floating-point ndarrays depending on a condition.
+*
+* ## Notes
+*
+* -   The function expects the following ndarrays:
+*
+*     -   a one-dimensional condition ndarray.
+*     -   first one-dimensional input ndarray.
+*     -   second one-dimensional input ndarray.
+*     -   a one-dimensional output ndarray.
+*
+* @param arrays - array-like object containing ndarrays
+* @returns output ndarray
+*
+* @example
+* var BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+* var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
+*
+* var condition = new BooleanVector( [ true, false, true, false, true ] );
+* var x = new Float64Vector( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+* var y = new Float64Vector( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+* var out = new Float64Vector( 5 );
+*
+* var v = dwhere( [ condition, x, y, out ] );
+* // returns <ndarray>[ 1.0, 7.0, 3.0, 9.0, 5.0 ]
+*/
+declare function dwhere( arrays: [ boolndarray, float64ndarray, float64ndarray, float64ndarray ] ): float64ndarray;
+
+
+// EXPORTS //
+
+export = dwhere;
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/test.ts b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/test.ts
new file mode 100644
index 000000000000..eb3bae908ccc
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/docs/types/test.ts
@@ -0,0 +1,72 @@
+/**
+* @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.
+*/
+
+/* eslint-disable space-in-parens */
+
+import zeros = require( '@stdlib/ndarray/zeros' );
+import BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+import dwhere = require( './index' );
+
+
+// TESTS //
+
+// The function returns an ndarray...
+{
+	const condition = new BooleanVector( 10 );
+	const x = zeros( [ 10 ], {
+		'dtype': 'float64'
+	});
+	const y = zeros( [ 10 ], {
+		'dtype': 'float64'
+	});
+	const out = zeros( [ 10 ], {
+		'dtype': 'float64'
+	});
+
+	dwhere( [ condition, x, y, out ] ); // $ExpectType float64ndarray
+}
+
+// The compiler throws an error if the function is provided a first argument which is not an array of ndarrays...
+{
+	dwhere( '10' ); // $ExpectError
+	dwhere( 5 ); // $ExpectError
+	dwhere( true ); // $ExpectError
+	dwhere( false ); // $ExpectError
+	dwhere( null ); // $ExpectError
+	dwhere( undefined ); // $ExpectError
+	dwhere( [] ); // $ExpectError
+	dwhere( {} ); // $ExpectError
+	dwhere( ( x: number ): number => x ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided an unsupported number of arguments...
+{
+	const condition = new BooleanVector( 10 );
+	const x = zeros( [ 10 ], {
+		'dtype': 'float64'
+	});
+	const y = zeros( [ 10 ], {
+		'dtype': 'float64'
+	});
+	const out = zeros( [ 10 ], {
+		'dtype': 'float64'
+	});
+
+	dwhere(); // $ExpectError
+	dwhere( [ condition, x, y, out ], {} ); // $ExpectError
+}
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/examples/index.js b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/examples/index.js
new file mode 100644
index 000000000000..0bcc5152a3fd
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/examples/index.js
@@ -0,0 +1,46 @@
+/**
+* @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';
+
+var bernoulli = require( '@stdlib/random/array/bernoulli' );
+var discreteUniform = require( '@stdlib/random/discrete-uniform' );
+var BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var dwhere = require( './../lib' );
+
+var opts = {
+	'dtype': 'float64'
+};
+
+var cbuf = bernoulli( 10, 0.5, {
+	'dtype': 'uint8'
+});
+var condition = new BooleanVector( cbuf.buffer );
+console.log( ndarray2array( condition ) );
+
+var x = discreteUniform( [ 10 ], -100, 100, opts );
+console.log( ndarray2array( x ) );
+
+var y = discreteUniform( [ 10 ], -100, 100, opts );
+console.log( ndarray2array( y ) );
+
+var out = discreteUniform( [ 10 ], -100, 100, opts );
+
+dwhere( [ condition, x, y, out ] );
+console.log( ndarray2array( out ) );
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/index.js b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/index.js
new file mode 100644
index 000000000000..cbece425eda9
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/index.js
@@ -0,0 +1,47 @@
+/**
+* @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';
+
+/**
+* Take elements from one of two one-dimensional double-precision floating-point ndarrays depending on a condition.
+*
+* @module @stdlib/blas/ext/base/ndarray/dwhere
+*
+* @example
+* var BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+* var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
+* var dwhere = require( '@stdlib/blas/ext/base/ndarray/dwhere' );
+*
+* var condition = new BooleanVector( [ true, false, true, false, true ] );
+* var x = new Float64Vector( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+* var y = new Float64Vector( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+* var out = new Float64Vector( 5 );
+*
+* var v = dwhere( [ condition, x, y, out ] );
+* // returns <ndarray>[ 1.0, 7.0, 3.0, 9.0, 5.0 ]
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/main.js b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/main.js
new file mode 100644
index 000000000000..29976aa9cc24
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/lib/main.js
@@ -0,0 +1,76 @@
+/**
+* @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 numelDimension = require( '@stdlib/ndarray/base/numel-dimension' );
+var getStride = require( '@stdlib/ndarray/base/stride' );
+var getOffset = require( '@stdlib/ndarray/base/offset' );
+var getData = require( '@stdlib/ndarray/base/data-buffer' );
+var strided = require( '@stdlib/blas/ext/base/dwhere' ).ndarray;
+
+
+// MAIN //
+
+/**
+* Takes elements from one of two one-dimensional double-precision floating-point ndarrays depending on a condition.
+*
+* ## Notes
+*
+* -   The function expects the following ndarrays:
+*
+*     -   a one-dimensional condition ndarray.
+*     -   first one-dimensional input ndarray.
+*     -   second one-dimensional input ndarray.
+*     -   a one-dimensional output ndarray.
+*
+* @param {ArrayLikeObject<Object>} arrays - array-like object containing ndarrays
+* @returns {ndarray} output ndarray
+*
+* @example
+* var BooleanVector = require( '@stdlib/ndarray/vector/bool' );
+* var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
+*
+* var condition = new BooleanVector( [ true, false, true, false, true ] );
+* var x = new Float64Vector( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+* var y = new Float64Vector( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+* var out = new Float64Vector( 5 );
+*
+* var v = dwhere( [ condition, x, y, out ] );
+* // returns <ndarray>[ 1.0, 7.0, 3.0, 9.0, 5.0 ]
+*/
+function dwhere( arrays ) {
+	var condition;
+	var out;
+	var x;
+	var y;
+
+	condition = arrays[ 0 ];
+	x = arrays[ 1 ];
+	y = arrays[ 2 ];
+	out = arrays[ 3 ];
+	strided( numelDimension( condition, 0 ), getData( condition ), getStride( condition, 0 ), getOffset( condition ), getData( x ), getStride( x, 0 ), getOffset( x ), getData( y ), getStride( y, 0 ), getOffset( y ), getData( out ), getStride( out, 0 ), getOffset( out ) ); // eslint-disable-line max-len
+	return out;
+}
+
+
+// EXPORTS //
+
+module.exports = dwhere;
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/package.json b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/package.json
new file mode 100644
index 000000000000..9b72b5b1910c
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/package.json
@@ -0,0 +1,73 @@
+{
+  "name": "@stdlib/blas/ext/base/ndarray/dwhere",
+  "version": "0.0.0",
+  "description": "Take elements from one of two one-dimensional double-precision floating-point ndarrays depending on a condition.",
+  "license": "Apache-2.0",
+  "author": {
+    "name": "The Stdlib Authors",
+    "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+  },
+  "contributors": [
+    {
+      "name": "The Stdlib Authors",
+      "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+    }
+  ],
+  "main": "./lib",
+  "directories": {
+    "benchmark": "./benchmark",
+    "doc": "./docs",
+    "example": "./examples",
+    "lib": "./lib",
+    "test": "./test"
+  },
+  "types": "./docs/types",
+  "scripts": {},
+  "homepage": "https://github.com/stdlib-js/stdlib",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/stdlib-js/stdlib.git"
+  },
+  "bugs": {
+    "url": "https://github.com/stdlib-js/stdlib/issues"
+  },
+  "dependencies": {},
+  "devDependencies": {},
+  "engines": {
+    "node": ">=0.10.0",
+    "npm": ">2.7.0"
+  },
+  "os": [
+    "aix",
+    "darwin",
+    "freebsd",
+    "linux",
+    "macos",
+    "openbsd",
+    "sunos",
+    "win32",
+    "windows"
+  ],
+  "keywords": [
+    "stdlib",
+    "stdmath",
+    "mathematics",
+    "math",
+    "blas",
+    "extended",
+    "ext",
+    "dwhere",
+    "where",
+    "condition",
+    "conditional",
+    "select",
+    "ternary",
+    "vector",
+    "strided",
+    "array",
+    "ndarray",
+    "float64",
+    "double"
+  ],
+  "__stdlib__": {}
+}
diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/test/test.js b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/test/test.js
new file mode 100644
index 000000000000..95b4daba8d2d
--- /dev/null
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/test/test.js
@@ -0,0 +1,412 @@
+/**
+* @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 tape = require( 'tape' );
+var isSameFloat64Array = require( '@stdlib/assert/is-same-float64array' );
+var Float64Array = require( '@stdlib/array/float64' );
+var BooleanArray = require( '@stdlib/array/bool' );
+var ndarray = require( '@stdlib/ndarray/base/ctor' );
+var dwhere = require( './../lib' );
+
+
+// FUNCTIONS //
+
+/**
+* Returns a one-dimensional double-precision floating-point ndarray.
+*
+* @private
+* @param {Float64Array} buffer - underlying data buffer
+* @param {NonNegativeInteger} length - number of indexed elements
+* @param {integer} stride - stride length
+* @param {NonNegativeInteger} offset - index offset
+* @returns {ndarray} one-dimensional ndarray
+*/
+function vector( buffer, length, stride, offset ) {
+	return new ndarray( 'float64', buffer, [ length ], [ stride ], offset, 'row-major' );
+}
+
+/**
+* Returns a one-dimensional boolean ndarray.
+*
+* @private
+* @param {BooleanArray} buffer - underlying data buffer
+* @param {NonNegativeInteger} length - number of indexed elements
+* @param {integer} stride - stride length
+* @param {NonNegativeInteger} offset - index offset
+* @returns {ndarray} one-dimensional ndarray
+*/
+function bvector( buffer, length, stride, offset ) {
+	return new ndarray( 'bool', buffer, [ length ], [ stride ], offset, 'row-major' );
+}
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+	t.ok( true, __filename );
+	t.strictEqual( typeof dwhere, 'function', 'main export is a function' );
+	t.end();
+});
+
+tape( 'the function has an arity of 1', function test( t ) {
+	t.strictEqual( dwhere.length, 1, 'has expected arity' );
+	t.end();
+});
+
+tape( 'the function selects elements from `x` or `y` based on a condition', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray( [ true, false, true, false, true ] );
+	xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+	ybuf = new Float64Array( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+	obuf = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );
+	c = bvector( cbuf, 5, 1, 0 );
+	x = vector( xbuf, 5, 1, 0 );
+	y = vector( ybuf, 5, 1, 0 );
+	out = vector( obuf, 5, 1, 0 );
+	expected = new Float64Array([
+		1.0,  // x[0]
+		7.0,  // y[1]
+		3.0,  // x[2]
+		9.0,  // y[3]
+		5.0   // x[4]
+	]);
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function selects elements from `x` or `y` based on a condition (all true)', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray( [ true, true, true, true, true ] );
+	xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+	ybuf = new Float64Array( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+	obuf = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );
+	c = bvector( cbuf, 5, 1, 0 );
+	x = vector( xbuf, 5, 1, 0 );
+	y = vector( ybuf, 5, 1, 0 );
+	out = vector( obuf, 5, 1, 0 );
+	expected = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function selects elements from `x` or `y` based on a condition (all false)', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray( [ false, false, false, false, false ] );
+	xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] );
+	ybuf = new Float64Array( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+	obuf = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );
+	c = bvector( cbuf, 5, 1, 0 );
+	x = vector( xbuf, 5, 1, 0 );
+	y = vector( ybuf, 5, 1, 0 );
+	out = vector( obuf, 5, 1, 0 );
+	expected = new Float64Array( [ 6.0, 7.0, 8.0, 9.0, 10.0 ] );
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function supports ndarrays having non-unit strides', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray([
+		true,  // 0
+		false,
+		false, // 1
+		true,
+		true,  // 2
+		false,
+		false, // 3
+		true
+	]);
+	xbuf = new Float64Array([
+		1.0, // 0
+		-2.0,
+		3.0, // 1
+		-4.0,
+		5.0, // 2
+		-6.0,
+		7.0, // 3
+		-8.0
+	]);
+	ybuf = new Float64Array([
+		11.0, // 0
+		-12.0,
+		13.0, // 1
+		-14.0,
+		15.0, // 2
+		-16.0,
+		17.0, // 3
+		-18.0
+	]);
+	obuf = new Float64Array( [ 0.0, 99.0, 0.0, 99.0, 0.0, 99.0, 0.0, 99.0 ] );
+	c = bvector( cbuf, 4, 2, 0 );
+	x = vector( xbuf, 4, 2, 0 );
+	y = vector( ybuf, 4, 2, 0 );
+	out = vector( obuf, 4, 2, 0 );
+	expected = new Float64Array([
+		1.0,  // x[0]
+		99.0,
+		13.0, // y[2]
+		99.0,
+		5.0,  // x[4]
+		99.0,
+		17.0, // y[6]
+		99.0
+	]);
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function supports ndarrays having negative strides', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray([
+		true,  // 4
+		false, // 3
+		true,  // 2
+		false, // 1
+		true   // 0
+	]);
+	xbuf = new Float64Array([
+		1.0, // 4
+		2.0, // 3
+		3.0, // 2
+		4.0, // 1
+		5.0  // 0
+	]);
+	ybuf = new Float64Array([
+		6.0,  // 4
+		7.0,  // 3
+		8.0,  // 2
+		9.0,  // 1
+		10.0  // 0
+	]);
+	obuf = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );
+	c = bvector( cbuf, 5, -1, 4 );
+	x = vector( xbuf, 5, -1, 4 );
+	y = vector( ybuf, 5, -1, 4 );
+	out = vector( obuf, 5, -1, 4 );
+	expected = new Float64Array([
+		1.0,  // x[0]
+		7.0,  // y[1]
+		3.0,  // x[2]
+		9.0,  // y[3]
+		5.0   // x[4]
+	]);
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function supports ndarrays having non-zero offsets', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray([
+		false,
+		false,
+		true,  // 0
+		false, // 1
+		true,  // 2
+		false
+	]);
+	xbuf = new Float64Array([
+		-1.0,
+		-2.0,
+		3.0, // 0
+		4.0, // 1
+		5.0, // 2
+		-6.0
+	]);
+	ybuf = new Float64Array([
+		-11.0,
+		-12.0,
+		13.0, // 0
+		14.0, // 1
+		15.0, // 2
+		-16.0
+	]);
+	obuf = new Float64Array( [ 99.0, 99.0, 0.0, 0.0, 0.0, 99.0 ] );
+	c = bvector( cbuf, 3, 1, 2 );
+	x = vector( xbuf, 3, 1, 2 );
+	y = vector( ybuf, 3, 1, 2 );
+	out = vector( obuf, 3, 1, 2 );
+	expected = new Float64Array([
+		99.0,
+		99.0,
+		3.0,  // x[2]
+		14.0, // y[3]
+		5.0,  // x[4]
+		99.0
+	]);
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function supports ndarrays having different strides and offsets', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray( [ false, true, false, true, false, false ] );
+	xbuf = new Float64Array( [ 1.0, 100.0, 2.0, 100.0, 3.0, 100.0, 4.0 ] );
+	ybuf = new Float64Array( [ 40.0, 30.0, 20.0, 10.0 ] );
+	obuf = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );
+	c = bvector( cbuf, 4, -1, 4 );
+	x = vector( xbuf, 4, 2, 0 );
+	y = vector( ybuf, 4, -1, 3 );
+	out = vector( obuf, 4, 3, 1 );
+	expected = new Float64Array([
+		0.0,
+		10.0, // cbuf[4] = false => y[3]
+		0.0,
+		0.0,
+		2.0,  // cbuf[3] = true => x[2]
+		0.0,
+		0.0,
+		30.0, // cbuf[2] = false => y[1]
+		0.0,
+		0.0,
+		4.0,  // cbuf[1] = true => x[6]
+		0.0
+	]);
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});
+
+tape( 'the function returns the output ndarray unchanged when the input ndarrays are empty', function test( t ) {
+	var expected;
+	var actual;
+	var cbuf;
+	var obuf;
+	var xbuf;
+	var ybuf;
+	var out;
+	var c;
+	var x;
+	var y;
+
+	cbuf = new BooleanArray( [] );
+	xbuf = new Float64Array( [] );
+	ybuf = new Float64Array( [] );
+	obuf = new Float64Array( [] );
+	c = bvector( cbuf, 0, 1, 0 );
+	x = vector( xbuf, 0, 1, 0 );
+	y = vector( ybuf, 0, 1, 0 );
+	out = vector( obuf, 0, 1, 0 );
+	expected = new Float64Array( [] );
+
+	actual = dwhere( [ c, x, y, out ] );
+	t.strictEqual( actual, out, 'returns expected value' );
+	t.strictEqual( isSameFloat64Array( obuf, expected ), true, 'returns expected value' );
+
+	t.end();
+});

From 5838489313b4161ba8202d42e99eae81d6c9a763 Mon Sep 17 00:00:00 2001
From: headlessNode <harriskhan047@outlook.com>
Date: Thu, 24 Sep 2026 15:03:43 +0500
Subject: [PATCH 2/2] fix: lint err

---
 .../base/ndarray/dwhere/benchmark/benchmark.js   | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js
index 0ba72635518c..8cdf2d004331 100644
--- a/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js
+++ b/lib/node_modules/@stdlib/blas/ext/base/ndarray/dwhere/benchmark/benchmark.js
@@ -47,13 +47,19 @@ var options = {
 * @returns {Function} benchmark function
 */
 function createBenchmark( len ) {
-	var cbuf = bernoulli( len, 0.5, {
+	var condition;
+	var cbuf;
+	var out;
+	var x;
+	var y;
+
+	cbuf = bernoulli( len, 0.5, {
 		'dtype': 'uint8'
 	});
-	var condition = new BooleanVector( cbuf.buffer );
-	var out = uniform( [ len ], -100.0, 100.0, options );
-	var x = uniform( [ len ], -100.0, 100.0, options );
-	var y = uniform( [ len ], -100.0, 100.0, options );
+	condition = new BooleanVector( cbuf.buffer );
+	out = uniform( [ len ], -100.0, 100.0, options );
+	x = uniform( [ len ], -100.0, 100.0, options );
+	y = uniform( [ len ], -100.0, 100.0, options );
 	return benchmark;
 
 	/**