feat: add blas/ext/copy-within

lib/node_modules/@stdlib/blas/ext/copy-within/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.
+
+-->
+
+# copyWithin
+
+> Perform an in-place copy of elements within an [ndarray][@stdlib/ndarray/ctor] along an [ndarray][@stdlib/ndarray/ctor] dimension.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var copyWithin = require( '@stdlib/blas/ext/copy-within' );
+```
+
+#### copyWithin( x, target, start\[, end]\[, options] )
+
+Performs an in-place copy of elements within an [ndarray][@stdlib/ndarray/ctor] along an [ndarray][@stdlib/ndarray/ctor] dimension.
+
+```javascript
+var array = require( '@stdlib/ndarray/array' );
+
+// Create an input ndarray:
+var x = array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
+// returns <ndarray>[ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ]
+
+// Perform operation:
+var y = copyWithin( x, 3, 1, 4 );
+// returns <ndarray>[ 1.0, 2.0, 3.0, 2.0, 3.0, 4.0 ]
+
+var bool = ( x === y );
+// returns true
+```
+
+The function has the following parameters:
+
+-   **x**: input [ndarray][@stdlib/ndarray/ctor].
+-   **target**: target index. May be either an integer or an [ndarray][@stdlib/ndarray/ctor] having an integer index or "generic" [data type][@stdlib/ndarray/dtypes]. If provided an [ndarray][@stdlib/ndarray/ctor], the value must have a shape which is [broadcast-compatible][@stdlib/ndarray/base/broadcast-shapes] with the complement of the shape defined by `options.dim`. For example, given the input shape `[2, 3, 4]` and `options.dim=0`, an [ndarray][@stdlib/ndarray/ctor] target index must have a shape which is [broadcast-compatible][@stdlib/ndarray/base/broadcast-shapes] with the shape `[3, 4]`.
+-   **start**: source start index (inclusive). May be either an integer or an [ndarray][@stdlib/ndarray/ctor] having an integer index or "generic" [data type][@stdlib/ndarray/dtypes] and following the same broadcasting semantics as the `target` argument.
+-   **end**: source end index (exclusive) (_optional_). May be either an integer or an [ndarray][@stdlib/ndarray/ctor] having an integer index or "generic" [data type][@stdlib/ndarray/dtypes] and following the same broadcasting semantics as the `target` argument. By default, the source end index is `N + 1`, where `N` is the number of elements along the dimension specified by `options.dim`.
+-   **options**: function options (_optional_).
+
+The function accepts the following options:
+
+-   **dim**: dimension over which to perform operation. If provided a negative integer, the dimension along which to perform the operation is determined by counting backward from the last dimension (where `-1` refers to the last dimension). Default: `-1`.
+
+When a `target`, `start`, and/or `end` index is negative, the respective index is determined relative to the last indexed element, with out-of-bounds indices clamped to index bounds.
+
+```javascript
+var array = require( '@stdlib/ndarray/array' );
+
+var x = array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 ] );
+
+var y = copyWithin( x, 0, -2 );
+// returns <ndarray>[ 5.0, 6.0, 3.0, 4.0, 5.0, 6.0 ]
+```
+
+By default, the function performs the operation over elements along the last dimension. To perform the operation over a different dimension, provide a `dim` option.
+
+```javascript
+var array = require( '@stdlib/ndarray/array' );
+
+var x = array( [ [ 1.0, 2.0, 3.0, 4.0 ], [ 5.0, 6.0, 7.0, 8.0 ] ] );
+
+var y = copyWithin( x, 1, 0, {
+    'dim': 0
+});
+// returns <ndarray>[ [ 1.0, 2.0, 3.0, 4.0 ], [ 1.0, 2.0, 3.0, 4.0 ] ]
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   The input [ndarray][@stdlib/ndarray/ctor] is copied **in-place** (i.e., the input [ndarray][@stdlib/ndarray/ctor] is **mutated**).
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/discrete-uniform' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var copyWithin = require( '@stdlib/blas/ext/copy-within' );
+
+// Generate an ndarray of random numbers:
+var x = discreteUniform( [ 5, 5 ], 0, 20, {
+    'dtype': 'generic'
+});
+console.log( ndarray2array( x ) );
+
+// Perform operation:
+copyWithin( x, -2, 0, 2, {
+    'dim': 0
+});
+
+// Print the results:
+console.log( ndarray2array( x ) );
+```
+
+</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">
+
+[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/ctor
+
+[@stdlib/ndarray/dtypes]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/dtypes
+
+[@stdlib/ndarray/base/broadcast-shapes]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/ndarray/base/broadcast-shapes
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/blas/ext/copy-within/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 isnan = require( '@stdlib/math/base/assert/is-nan' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var uniform = require( '@stdlib/random/uniform' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var copyWithin = require( './../lib' );
+
+
+// VARIABLES //
+
+var options = {
+	'dtype': 'float64'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var x = uniform( [ len ], -50.0, 50.0, options );
+	return benchmark;
+
+	/**
+	* Benchmark function.
+	*
+	* @private
+	* @param {Benchmark} b - benchmark instance
+	*/
+	function benchmark( b ) {
+		var o;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			o = copyWithin( x, 1, 0, len-1 );
+			if ( typeof o !== 'object' ) {
+				b.fail( 'should return an ndarray' );
+			}
+		}
+		b.toc();
+		if ( isnan( o.get( i%len ) ) ) {
+			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:dtype=%s,len=%d', pkg, options.dtype, len ), f );
+	}
+}
+
+main();

lib/node_modules/@stdlib/blas/ext/copy-within/docs/repl.txt

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+
+{{alias}}( x, target, start[, end][, options] )
+    Performs an in-place copy of elements within an ndarray along an ndarray
+    dimension.
+
+    When a `target`, `start`, and/or `end` index is negative, the respective
+    index is determined relative to the last indexed element, with out-of-bounds
+    indices clamped to index bounds.
+
+    The function copies elements within an input ndarray in-place and thus
+    mutates an input ndarray.
+
+    Parameters
+    ----------
+    x: ndarray
+        Input array.
+
+    target: ndarray|integer
+        Target index. May be either an integer or an ndarray having an integer
+        index or "generic" data type. If provided an ndarray, the value must
+        have a shape which is broadcast compatible with the complement of the
+        shape defined by `options.dim`. For example, given the input shape
+        `[2, 3, 4]` and `options.dim=0`, an ndarray target index must have a
+        shape which is broadcast compatible with the shape `[3, 4]`.
+
+    start: ndarray|integer
+        Source start index (inclusive). May be either an integer or an ndarray
+        having an integer index or "generic" data type and following the same
+        broadcasting semantics as the `target` argument.
+
+    end: ndarray|integer (optional)
+        Source end index (exclusive). May be either an integer or an ndarray
+        having an integer index or "generic" data type and following the same
+        broadcasting semantics as the `target` argument. Default: `N + 1` where
+        `N` is the number of elements along the operation dimension.
+
+    options: Object (optional)
+        Function options.
+
+    options.dim: integer (optional)
+        Dimension over which to perform operation. If provided a negative
+        integer, the dimension along which to perform the operation is
+        determined by counting backward from the last dimension (where `-1`
+        refers to the last dimension). Default: `-1`.
+
+    Returns
+    -------
+    out: ndarray
+        Input array.
+
+    Examples
+    --------
+    > var x = {{alias:@stdlib/ndarray/array}}( [ 1.0, 2.0, 3.0, 4.0 ] );
+    > var y = {{alias}}( x, 2, 0 )
+    <ndarray>[ 1.0, 2.0, 1.0, 2.0 ]
+    > var bool = ( x === y )
+    true
+
+    See Also
+    --------
+