feat: add ndarray/base/flatten-shape-from

lib/node_modules/@stdlib/ndarray/base/flatten-shape-from/README.md

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+<!--
+
+@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.
+
+-->
+
+# flattenShapeFrom
+
+> Flatten a shape starting from a specified dimension.
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- Package usage documentation. -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var flattenShapeFrom = require( '@stdlib/ndarray/base/flatten-shape-from' );
+```
+
+#### flattenShapeFrom( shape, dim )
+
+Flattens a shape starting from a specified dimension.
+
+```javascript
+var sh = flattenShapeFrom( [ 3, 3, 2 ], 1 );
+// returns [ 3, 6 ]
+```
+
+The function accepts the following parameters:
+
+-   **shape**: array shape.
+-   **dim**: dimension to start flattening from.
+
+#### flattenShapeFrom.assign( shape, dim, out )
+
+Flattens a shape starting from a specified dimension and assigns results to a provided output array.
+
+```javascript
+var sh = [ 0, 0 ];
+
+var out = flattenShapeFrom.assign( [ 3, 3, 2 ], 1, sh );
+// returns [ 3, 6 ]
+
+var bool = ( sh === out );
+// returns true
+```
+
+The function accepts the following parameters:
+
+-   **shape**: array shape.
+-   **dim**: dimension to start flattening from. If provided an integer less than zero, the dimension index is resolved relative to the last dimension, with the last dimension corresponding to the value `-1`.
+-   **out**: output array.
+
+</section>
+
+<!-- /.usage -->
+
+<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- Package usage examples. -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
+var zip = require( '@stdlib/array/base/zip' );
+var logEachMap = require( '@stdlib/console/log-each-map' );
+var flattenShapeFrom = require( '@stdlib/ndarray/base/flatten-shape-from' );
+
+var opts = {
+    'dtype': 'int32'
+};
+var d1 = discreteUniform( 100, 1, 10, opts );
+var d2 = discreteUniform( d1.length, 1, 10, opts );
+var d3 = discreteUniform( d1.length, 1, 10, opts );
+var d4 = discreteUniform( d1.length, 1, 10, opts );
+
+var dims = discreteUniform( d1.length, -4, 3, opts );
+var shapes = zip( [ d1, d2, d3, d4 ] );
+
+logEachMap( 'shape: (%s). dim: %d. flattened: (%s).', shapes, dims, flattenShapeFrom );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<!-- C usage documentation. -->
+
+<section class="usage">
+
+### Usage
+
+```c
+#include "stdlib/ndarray/base/flatten_shape_from.h"
+```
+
+#### stdlib_ndarray_flatten_shape_from( ndims, \*shape, dim, \*out )
+
+Flattens a shape starting from a specified dimension.
+
+```c
+const int64_t ndims = 3;
+const int64_t shape[] = { 2, 3, 10 };
+int64_t out[ 2 ];
+
+stdlib_ndarray_flatten_shape( ndims, shape, 1, out );
+```
+
+The function accepts the following arguments:
+
+-   **ndims**: `[in] int64_t` number of dimensions.
+-   **shape**: `[in] int64_t*` array shape (dimensions).
+-   **dim**: `[in] int64_t` dimension to start flattening from.
+-   **out**: `[out] int64_t*` output array.
+
+```c
+int8_t stdlib_ndarray_flatten_shape_from( const int64_t ndims, const int64_t *shape, const int64_t dim, int64_t *out );
+```
+
+</section>
+
+<!-- /.usage -->
+
+<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<section class="notes">
+
+</section>
+
+<!-- /.notes -->
+
+<!-- C API usage examples. -->
+
+<section class="examples">
+
+### Examples
+
+```c
+#include "stdlib/ndarray/base/flatten_shape_from.h"
+#include <stdio.h>
+#include <inttypes.h>
+
+int main( void ) {
+    const int64_t shape[] = { 2, 3, 4, 10 };
+    const int64_t ndims = 4;
+    const int64_t dim = 2;
+    int64_t out[ 3 ];
+
+    stdlib_ndarray_flatten_shape_from( ndims, shape, dim, out );
+
+    int i;
+    printf( "shape = ( " );
+    for ( i = 0; i < ndims-dim+1; i++ ) {
+        printf( "%"PRId64"", out[ i ] );
+        if ( i < ndims-dim ) {
+            printf( ", " );
+        }
+    }
+    printf( " )\n" );
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
+<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
+
+<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 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 -->

lib/node_modules/@stdlib/ndarray/base/flatten-shape-from/benchmark/benchmark.js

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+/**
+* @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 discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
+var isArray = require( '@stdlib/assert/is-array' );
+var pkg = require( './../package.json' ).name;
+var flattenShapeFrom = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var shape;
+	var out;
+	var i;
+
+	shape = discreteUniform( 5, 1, 10, {
+		'dtype': 'generic'
+	});
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		shape[ 0 ] += 1;
+		out = flattenShapeFrom( shape, 0 );
+		if ( out.length !== 1 ) {
+			b.fail( 'should have expected length' );
+		}
+	}
+	b.toc();
+	if ( !isArray( out ) ) {
+		b.fail( 'should return an array' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( pkg+':assign', function benchmark( b ) {
+	var shape;
+	var out;
+	var i;
+
+	shape = discreteUniform( 5, 1, 10, {
+		'dtype': 'generic'
+	});
+
+	out = [ 0 ];
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		shape[ 0 ] += 1;
+		out = flattenShapeFrom.assign( shape, 0, out );
+		if ( out.length !== 1 ) {
+			b.fail( 'should have expected length' );
+		}
+	}
+	b.toc();
+	if ( !isArray( out ) ) {
+		b.fail( 'should return an array' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});