feat: add blas/ext/base/gfind-index

lib/node_modules/@stdlib/blas/ext/base/gfind-index/README.md

@@ -0,0 +1,229 @@
+<!--
+
+@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.
+
+-->
+
+# gfindIndex
+
+> Return the index of the first element which passes a test implemented by a predicate function.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var gfindIndex = require( '@stdlib/blas/ext/base/gfind-index' );
+```
+
+#### gfindIndex( N, x, strideX, clbk\[, thisArg] )
+
+Returns the index of the first element which passes a test implemented by a predicate function.
+
+```javascript
+function isEven( v ) {
+    return v % 2.0 === 0.0;
+}
+
+var x = [ 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];
+
+var idx = gfindIndex( x.length, x, 1, isEven );
+// returns 3
+```
+
+If the function is unable to find an element, the function returns `-1`.
+
+```javascript
+function isEven( v ) {
+    return v % 2.0 === 0.0;
+}
+
+var x = [ 1.0, 3.0, 5.0, 7.0, 9.0 ];
+
+var idx = gfindIndex( x.length, x, 1, isEven );
+// returns -1
+```
+
+The function has the following parameters:
+
+-   **N**: number of indexed elements.
+-   **x**: input array.
+-   **strideX**: stride length.
+-   **clbk**: callback function.
+-   **thisArg**: execution context (_optional_).
+
+The callback function is provided the following arguments:
+
+-   **value**: current array element.
+-   **aidx**: array index.
+-   **sidx**: strided index (`offset + aidx*stride`).
+-   **array**: the input array.
+
+To set the callback execution context, provide a `thisArg`.
+
+```javascript
+function isEven( v ) {
+    this.count += 1;
+    return v % 2.0 === 0.0;
+}
+
+var x = [ 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];
+
+var ctx = {
+    'count': 0
+};
+
+var idx = gfindIndex( x.length, x, 1, isEven, ctx );
+// returns 3
+
+var count = ctx.count;
+// returns 4
+```
+
+The `N` and stride parameters determine which elements in the strided array are accessed at runtime. For example, to check every other element:
+
+```javascript
+function isEven( v ) {
+    return v % 2.0 === 0.0;
+}
+
+var x = [ 1.0, 3.0, -5.0, 0.0, 4.0, -1.0, -3.0 ];
+
+var idx = gfindIndex( 4, x, 2, isEven );
+// returns 2
+```
+
+Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.
+
+```javascript
+var Float64Array = require( '@stdlib/array/float64' );
+
+function isEven( v ) {
+    return v % 2.0 === 0.0;
+}
+
+// Initial array...
+var x0 = new Float64Array( [ 1.0, 3.0, 4.0, -5.0, 7.0, 6.0 ] );
+
+// Create an offset view...
+var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
+
+var idx = gfindIndex( 3, x1, 2, isEven );
+// returns 2
+```
+
+#### gfindIndex.ndarray( N, x, strideX, offsetX, clbk\[, thisArg] )
+
+Returns the index of the first element which passes a test implemented by a predicate function using alternative indexing semantics.
+
+```javascript
+function isEven( v ) {
+    return v % 2.0 === 0.0;
+}
+
+var x = [ 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];
+
+var idx = gfindIndex.ndarray( x.length, x, 1, 0, isEven );
+// returns 3
+```
+
+The function has the following additional parameters:
+
+-   **offsetX**: starting index.
+
+While [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying buffer, the offset parameter supports indexing semantics based on a starting index. For example, to access only the last three elements:
+
+```javascript
+function isEven( v ) {
+    return v % 2.0 === 0.0;
+}
+
+var x = [ 1.0, -2.0, -4.0, 5.0, -7.0, 6.0 ];
+
+var idx = gfindIndex.ndarray( 3, x, 1, x.length-3, isEven );
+// returns 2
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   If `N <= 0`, both functions return `-1`.
+-   Both functions support array-like objects having getter and setter accessors for array element access (e.g., [`@stdlib/array/base/accessor`][@stdlib/array/base/accessor]).
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
+var gfindIndex = require( '@stdlib/blas/ext/base/gfind-index' );
+
+function isEven( v ) {
+    return v % 2.0 === 0.0;
+}
+
+var x = discreteUniform( 10, -100, 100, {
+    'dtype': 'generic'
+});
+console.log( x );
+
+var idx = gfindIndex( x.length, x, 1, isEven );
+console.log( idx );
+```
+
+</section>
+
+<!-- /.examples -->
+
+<!-- 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">
+
+[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray
+
+[@stdlib/array/base/accessor]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/base/accessor
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/blas/ext/base/gfind-index/benchmark/benchmark.js

@@ -0,0 +1,96 @@
+/**
+* @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 isInteger = require( '@stdlib/math/base/assert/is-integer' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var pkg = require( './../package.json' ).name;
+var gfindIndex = require( './../lib' );
+
+
+// FUNCTIONS //
+
+/**
+* Callback function.
+*
+* @param {*} v - array element
+* @returns {boolean} result
+*/
+function isEven( v ) {
+	return v % 2 === 0;
+}
+
+/**
+* Create a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var x = discreteUniform( len, -100.0, 100.0, {
+		'dtype': 'generic'
+	});
+	return benchmark;
+
+	function benchmark( b ) {
+		var idx;
+		var i;
+
+		b.tic();
+		for ( i = 0; i < b.iterations; i++ ) {
+			idx = gfindIndex( x.length, x, 1, isEven );
+			if ( !isInteger( idx ) ) {
+				b.fail( 'should return an integer' );
+			}
+		}
+		b.toc();
+		if ( !isInteger( idx ) ) {
+			b.fail( 'should return an integer' );
+		}
+		b.pass( 'benchmark finished' );
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+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( pkg+':len='+len, f );
+	}
+}
+
+main();