feat: add array/base/flatten3d-by

lib/node_modules/@stdlib/array/base/flatten3d-by/README.md

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+<!--
+
+@license Apache-2.0
+
+Copyright (c) 2023 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.
+
+-->
+
+<!-- lint disable maximum-heading-length -->
+
+# flatten3dBy
+
+> Flatten a three-dimensional nested array according to a callback function.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var flatten3dBy = require( '@stdlib/array/base/flatten3d-by' );
+```
+
+#### flatten3dBy( x, shape, colexicographic, clbk\[, thisArg] )
+
+Flattens a three-dimensional nested array according to a callback function.
+
+```javascript
+function scale( v ) {
+    return v * 2;
+}
+
+var x = [ [ [ 1, 2 ] ], [ [ 3, 4 ] ] ];
+
+var out = flatten3dBy( x, [ 2, 1, 2 ], false, scale );
+// returns [ 2, 4, 6, 8 ]
+```
+
+To flatten in colexicographic order, provide a third argument equal to `true`.
+
+```javascript
+function scale( v ) {
+    return v * 2;
+}
+
+var x = [ [ [ 1, 2 ] ], [ [ 3, 4 ] ] ];
+
+var out = flatten3dBy( x, [ 2, 1, 2 ], true, scale );
+// returns [ 2, 6, 4, 8 ]
+```
+
+To set the callback execution context, provide a `thisArg` argument.
+
+<!-- eslint-disable no-invalid-this -->
+
+```javascript
+function scale( v ) {
+    this.count += 1;
+    return v * 2;
+}
+
+var x = [ [ [ 1, 2 ], [ 3, 4 ] ] ];
+var ctx = {
+    'count': 0
+};
+
+var out = flatten3dBy( x, [ 1, 2, 2 ], false, scale, ctx );
+// returns [ 2, 4, 6, 8 ]
+
+var count = ctx.count;
+// returns 4
+```
+
+#### flatten3dBy.assign( x, shape, colexicographic, out, stride, offset, clbk\[, thisArg] )
+
+Flattens a three-dimensional nested array according to a callback function and assigns elements to a provided output array.
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+function scale( v ) {
+    return v * 2;
+}
+
+var x = [ [ [ 1, 2 ] ], [ [ 3, 4 ] ] ];
+var out = new Float64Array( 4 );
+
+var y = flatten3dBy.assign( x, [ 2, 1, 2 ], false, out, 1, 0, scale );
+// returns <Float64Array>[ 1, 2, 3, 4 ]
+
+var bool = ( y === out );
+// returns true
+
+y = flatten3dBy.assign( x, [ 2, 1, 2 ], true, out, 1, 0, scale );
+// returns <Float64Array>[ 1, 3, 2, 4 ]
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   A callback function is provided the following arguments:
+
+    -   **value**: nested array element.
+    -   **indices**: element indices (in lexicographic order).
+    -   **arr**: the input array.
+
+-   Both functions assume that all nested arrays have the same length (i.e., the input array is **not** a ragged array).
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var naryFunction = require( '@stdlib/utils/nary-function' );
+var abs = require( '@stdlib/math/base/special/abs' );
+var flatten3dBy = require( '@stdlib/array/base/flatten3d-by' );
+
+var fcn = naryFunction( abs, 1 );
+
+var x = [
+    [ [ -1, -2 ], [ -3, -4 ] ],
+    [ [ -5, -6 ], [ -7, -8 ] ],
+    [ [ -9, -10 ], [ -11, -12 ] ],
+    [ [ -13, -14 ], [ -15, -16 ] ]
+];
+
+var out = flatten3dBy( x, [ 0, 0, 0 ], false, fcn );
+// returns []
+
+out = flatten3dBy( x, [ 0, 0, 0 ], true, fcn );
+// returns []
+
+out = flatten3dBy( x, [ 1, 1, 1 ], false, fcn );
+// returns [ 1 ]
+
+out = flatten3dBy( x, [ 1, 1, 1 ], true, fcn );
+// returns [ 1 ]
+
+out = flatten3dBy( x, [ 2, 2, 2 ], false, fcn );
+// returns [ 1, 2, 3, 4, 5, 6, 7, 8 ]
+
+out = flatten3dBy( x, [ 2, 2, 2 ], true, fcn );
+// returns [ 1, 5, 3, 7, 2, 6, 4, 8 ]
+
+out = flatten3dBy( x, [ 3, 2, 2 ], false, fcn );
+// returns [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ]
+
+out = flatten3dBy( x, [ 3, 2, 2 ], true, fcn );
+// returns [ 1, 5, 9, 3, 7, 11, 2, 6, 10, 4, 8, 12 ]
+
+out = flatten3dBy( x, [ 4, 2, 2 ], false, fcn );
+// returns [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 ]
+
+out = flatten3dBy( x, [ 4, 2, 2 ], true, fcn );
+// returns [ 1, 5, 9, 13, 3, 7, 11, 15, 2, 6, 10, 14, 4, 8, 12, 16 ]
+```
+
+</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 -->

lib/node_modules/@stdlib/array/base/flatten3d-by/benchmark/benchmark.js

@@ -0,0 +1,143 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2023 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 isArray = require( '@stdlib/assert/is-array' );
+var isFloat64Array = require( '@stdlib/assert/is-float64array' );
+var zeroTo = require( '@stdlib/array/base/zero-to' );
+var filled = require( '@stdlib/array/base/filled' );
+var Float64Array = require( '@stdlib/array/float64' );
+var pkg = require( './../package.json' ).name;
+var flatten3dBy = require( './../lib' );
+
+
+// FUNCTIONS //
+
+/**
+* Scales an input value.
+*
+* @private
+* @param {number} v - input value
+* @returns {number} output value
+*
+* @example
+* var v = scale( 2.0 );
+* // returns 4.0
+*/
+function scale( v ) {
+	return v * 2.0;
+}
+
+
+// MAIN //
+
+bench( pkg+':size=125,lexicographic', function benchmark( b ) {
+	var x;
+	var i;
+	var v;
+
+	x = filled( filled( zeroTo( 5 ), 5 ), 5 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		v = flatten3dBy( x, [ 5, 5, 5 ], false, scale );
+		if ( typeof v !== 'object' ) {
+			b.fail( 'should return an array' );
+		}
+	}
+	b.toc();
+	if ( !isArray( v ) ) {
+		b.fail( 'should return an array' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( pkg+':size=125,colexicographic', function benchmark( b ) {
+	var x;
+	var i;
+	var v;
+
+	x = filled( filled( zeroTo( 5 ), 5 ), 5 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		v = flatten3dBy( x, [ 5, 5, 5 ], true, scale );
+		if ( typeof v !== 'object' ) {
+			b.fail( 'should return an array' );
+		}
+	}
+	b.toc();
+	if ( !isArray( v ) ) {
+		b.fail( 'should return an array' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( pkg+':assign:size=125,lexicographic', function benchmark( b ) {
+	var out;
+	var x;
+	var i;
+	var v;
+
+	out = new Float64Array( 125 );
+	x = filled( filled( zeroTo( 5 ), 5 ), 5 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		v = flatten3dBy.assign( x, [ 5, 5, 5 ], false, out, 1, 0, scale );
+		if ( typeof v !== 'object' ) {
+			b.fail( 'should return a Float64Array' );
+		}
+	}
+	b.toc();
+	if ( !isFloat64Array( v ) ) {
+		b.fail( 'should return a Float64Array' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});
+
+bench( pkg+':assign:size=125,colexicographic', function benchmark( b ) {
+	var out;
+	var x;
+	var i;
+	var v;
+
+	out = new Float64Array( 125 );
+	x = filled( filled( zeroTo( 5 ), 5 ), 5 );
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		v = flatten3dBy.assign( x, [ 5, 5, 5 ], true, out, 1, 0, scale );
+		if ( typeof v !== 'object' ) {
+			b.fail( 'should return a Float64Array' );
+		}
+	}
+	b.toc();
+	if ( !isFloat64Array( v ) ) {
+		b.fail( 'should return a Float64Array' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});