feat: add ndarray/some-by

lib/node_modules/@stdlib/ndarray/some-by/README.md

@@ -0,0 +1,389 @@
+<!--
+
+@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.
+
+-->
+
+# someBy
+
+> Test whether at least `n` elements in an [`ndarray`][@stdlib/ndarray/ctor] pass a test implemented by a predicate function along one or more dimensions.
+
+<section class="intro">
+
+</section>
+
+<!-- /.intro -->
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var someBy = require( '@stdlib/ndarray/some-by' );
+```
+
+#### someBy( x, n\[, options], predicate\[, thisArg] )
+
+Tests whether at least `n` elements in an [`ndarray`][@stdlib/ndarray/ctor] pass a test implemented by a predicate function along one or more dimensions.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray = require( '@stdlib/ndarray/ctor' );
+
+function predicate( value ) {
+    return value > 0.0;
+}
+
+// Create a data buffer:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
+
+// Define the shape of the input array:
+var sh = [ 3, 1, 2 ];
+
+// Define the array strides:
+var sx = [ 4, 4, 1 ];
+
+// Define the index offset:
+var ox = 1;
+
+// Create an input ndarray:
+var x = new ndarray( 'float64', xbuf, sh, sx, ox, 'row-major' );
+
+// Perform reduction:
+var out = someBy( x, 2, predicate );
+// returns <ndarray>
+
+console.log( out.get() );
+// => true
+```
+
+The function accepts the following arguments:
+
+-   **x**: input [`ndarray`][@stdlib/ndarray/ctor].
+-   **n**: number of elements which must pass the test implemented by a predicate function. May be either a scalar or an [`ndarray`][@stdlib/ndarray/ctor].
+-   **options**: function options (_optional_).
+-   **predicate**: predicate function.
+-   **thisArg**: predicate execution context (_optional_).
+
+The function accepts the following `options`:
+
+-   **dims**: list of dimensions over which to perform a reduction.
+-   **keepdims**: boolean indicating whether the reduced dimensions should be included in the returned [`ndarray`][@stdlib/ndarray/ctor] as singleton dimensions. Default: `false`.
+
+By default, the function performs a reduction over all elements in a provided [`ndarray`][@stdlib/ndarray/ctor]. To reduce specific dimensions, set the `dims` option.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray = require( '@stdlib/ndarray/ctor' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+
+function predicate( value ) {
+    return value > 0.0;
+}
+
+// Create a data buffer:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
+
+// Define the shape of the input array:
+var sh = [ 3, 1, 2 ];
+
+// Define the array strides:
+var sx = [ 4, 4, 1 ];
+
+// Define the index offset:
+var ox = 1;
+
+// Create an input ndarray:
+var x = new ndarray( 'float64', xbuf, sh, sx, ox, 'row-major' );
+
+var opts = {
+    'dims': [ 0, 1 ]
+};
+
+// Perform reduction:
+var out = someBy( x, 2, opts, predicate );
+// returns <ndarray>
+
+var v = ndarray2array( out );
+// returns [ true, true ]
+```
+
+By default, the function returns an [`ndarray`][@stdlib/ndarray/ctor] having a shape matching only the non-reduced dimensions of the input [`ndarray`][@stdlib/ndarray/ctor] (i.e., the reduced dimensions are dropped). To include the reduced dimensions as singleton dimensions in the output [`ndarray`][@stdlib/ndarray/ctor], set the `keepdims` option to `true`.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray = require( '@stdlib/ndarray/ctor' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+
+function predicate( value ) {
+    return value > 0.0;
+}
+
+// Create a data buffer:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
+
+// Define the shape of the input array:
+var sh = [ 3, 1, 2 ];
+
+// Define the array strides:
+var sx = [ 4, 4, 1 ];
+
+// Define the index offset:
+var ox = 1;
+
+// Create an input ndarray:
+var x = new ndarray( 'float64', xbuf, sh, sx, ox, 'row-major' );
+
+var opts = {
+    'dims': [ 0, 1 ],
+    'keepdims': true
+};
+
+// Perform reduction:
+var out = someBy( x, 2, opts, predicate );
+// returns <ndarray>
+
+var v = ndarray2array( out );
+// returns [[[ true, true ]]]
+```
+
+To set the predicate function execution context, provide a `thisArg`.
+
+<!-- eslint-disable no-invalid-this, max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray = require( '@stdlib/ndarray/ctor' );
+
+function predicate( value ) {
+    this.count += 1;
+    return value > 0.0;
+}
+
+// Create a data buffer:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
+
+// Define the shape of the input array:
+var sh = [ 3, 1, 2 ];
+
+// Define the array strides:
+var sx = [ 4, 4, 1 ];
+
+// Define the index offset:
+var ox = 1;
+
+// Create an input ndarray:
+var x = new ndarray( 'float64', xbuf, sh, sx, ox, 'row-major' );
+
+// Create a context object:
+var ctx = {
+    'count': 0
+};
+
+// Perform operation:
+var out = someBy( x, 2, predicate, ctx );
+// returns <ndarray>
+
+var v = out.get();
+// returns true
+
+var count = ctx.count;
+// returns 2
+```
+
+#### someBy.assign( x, n, out\[, options], predicate\[, thisArg] )
+
+Test whether at least `n` elements in an [`ndarray`][@stdlib/ndarray/ctor] pass a test implemented by a predicate function along one or more dimensions and assigns results to a provided output [`ndarray`][@stdlib/ndarray/ctor].
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray = require( '@stdlib/ndarray/ctor' );
+var empty = require( '@stdlib/ndarray/empty' );
+
+function predicate( value ) {
+    return value > 0.0;
+}
+
+// Create a data buffer:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
+
+// Define the shape of the input array:
+var sh = [ 3, 1, 2 ];
+
+// Define the array strides:
+var sx = [ 4, 4, 1 ];
+
+// Define the index offset:
+var ox = 1;
+
+// Create an input ndarray:
+var x = new ndarray( 'float64', xbuf, sh, sx, ox, 'row-major' );
+
+// Create an output ndarray:
+var y = empty( [], {
+    'dtype': 'bool'
+});
+
+// Perform reduction:
+var out = someBy.assign( x, 2, y, predicate );
+// returns <ndarray>
+
+var bool = ( out === y );
+// returns true
+
+var v = y.get();
+// returns true
+```
+
+The function accepts the following arguments:
+
+-   **x**: input [`ndarray`][@stdlib/ndarray/ctor].
+-   **n**: number of elements which must pass the test implemented by a predicate function. May be either a scalar or an [`ndarray`][@stdlib/ndarray/ctor].
+-   **out**: output [`ndarray`][@stdlib/ndarray/ctor]. The output [`ndarray`][@stdlib/ndarray/ctor] must have a shape matching the non-reduced dimensions of the input [`ndarray`][@stdlib/ndarray/ctor].
+-   **options**: function options (_optional_).
+-   **predicate**: predicate function.
+-   **thisArg**: predicate execution context (_optional_).
+
+The function accepts the following `options`:
+
+-   **dims**: list of dimensions over which to perform a reduction.
+
+By default, the function performs a reduction over all elements in a provided [`ndarray`][@stdlib/ndarray/ctor]. To reduce specific dimensions, set the `dims` option.
+
+<!-- eslint-disable max-len -->
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+var ndarray = require( '@stdlib/ndarray/ctor' );
+var empty = require( '@stdlib/ndarray/empty' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+
+function predicate( value ) {
+    return value > 0.0;
+}
+
+// Create a data buffer:
+var xbuf = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, 12.0 ] );
+
+// Define the shape of the input array:
+var sh = [ 3, 1, 2 ];
+
+// Define the array strides:
+var sx = [ 4, 4, 1 ];
+
+// Define the index offset:
+var ox = 1;
+
+// Create an input ndarray:
+var x = new ndarray( 'float64', xbuf, sh, sx, ox, 'row-major' );
+
+// Create an output ndarray:
+var y = empty( [ 2 ], {
+    'dtype': 'bool'
+});
+
+var opts = {
+    'dims': [ 0, 1 ]
+};
+
+// Perform reduction:
+var out = someBy.assign( x, 2, y, opts, predicate );
+
+var bool = ( out === y );
+// returns true
+
+var v = ndarray2array( y );
+// returns [ true, true ]
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   The predicate function is provided the following arguments:
+
+    -   **value**: current array element.
+    -   **indices**: current array element indices.
+    -   **arr**: the input ndarray.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/base/discrete-uniform' ).factory;
+var isEven = require( '@stdlib/assert/is-even' ).isPrimitive;
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
+var fillBy = require( '@stdlib/ndarray/fill-by' );
+var zeros = require( '@stdlib/ndarray/zeros' );
+var someBy = require( '@stdlib/ndarray/some-by' );
+
+var x = zeros( [ 2, 4, 5 ], {
+    'dtype': 'float64'
+});
+x = fillBy( x, discreteUniform( 0, 10 ) );
+console.log( ndarray2array( x ) );
+
+var n = scalar2ndarray( 4, {
+    'dtype': 'int8'
+});
+var y = someBy( x, n, isEven );
+console.log( y.get() );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- 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
+
+<!-- <related-links> -->
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->