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returned=1 errno=0 peeraddr=140.82.121.5:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["accessor","apply","array","base","binary","callback","clbk","foreach","javascript","map","ndarray","node","node-js","nodejs","stdlib","strided","transform"],"created_at":"2024-10-02T19:10:15.309Z","updated_at":"2026-03-08T19:31:23.361Z","avatar_url":"https://github.com/stdlib-js.png","language":"JavaScript","funding_links":["https://github.com/sponsors/stdlib-js","https://opencollective.com/stdlib","https://tidelift.com/funding/github/npm/@stdlib/stdlib"],"categories":[],"sub_categories":[],"readme":"\u003c!--\n\n@license Apache-2.0\n\nCopyright (c) 2021 The Stdlib Authors.\n\nLicensed under the Apache License, Version 2.0 (the \"License\");\nyou may not use this file except in compliance with the License.\nYou may obtain a copy of the License at\n\n   http://www.apache.org/licenses/LICENSE-2.0\n\nUnless required by applicable law or agreed to in writing, software\ndistributed under the License is distributed on an \"AS IS\" BASIS,\nWITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\nSee the License for the specific language governing permissions and\nlimitations under the License.\n\n--\u003e\n\n\u003c!-- lint disable maximum-heading-length --\u003e\n\n\n\u003cdetails\u003e\n  \u003csummary\u003e\n    About stdlib...\n  \u003c/summary\u003e\n  \u003cp\u003eWe believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.\u003c/p\u003e\n  \u003cp\u003eThe library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.\u003c/p\u003e\n  \u003cp\u003eWhen you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.\u003c/p\u003e\n  \u003cp\u003eTo join us in bringing numerical computing to the web, get started by checking us out on \u003ca href=\"https://github.com/stdlib-js/stdlib\"\u003eGitHub\u003c/a\u003e, and please consider \u003ca href=\"https://opencollective.com/stdlib\"\u003efinancially supporting stdlib\u003c/a\u003e. We greatly appreciate your continued support!\u003c/p\u003e\n\u003c/details\u003e\n\n# mapBy2\n\n[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] \u003c!-- [![dependencies][dependencies-image]][dependencies-url] --\u003e\n\n\u003e Apply a binary function to each pair of elements retrieved from strided input arrays according to a callback function and assign results to a strided output array.\n\n\u003csection class=\"intro\"\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.intro --\u003e\n\n\u003csection class=\"installation\"\u003e\n\n## Installation\n\n```bash\nnpm install @stdlib/strided-base-map-by2\n```\n\nAlternatively,\n\n-   To load the package in a website via a `script` tag without installation and bundlers, use the [ES Module][es-module] available on the [`esm`][esm-url] branch (see [README][esm-readme]).\n-   If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).\n-   For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [`umd`][umd-url] branch (see [README][umd-readme]).\n\nThe [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.\n\nTo view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.\n\n\u003c/section\u003e\n\n\u003csection class=\"usage\"\u003e\n\n## Usage\n\n```javascript\nvar mapBy2 = require( '@stdlib/strided-base-map-by2' );\n```\n\n#### mapBy2( N, x, strideX, y, strideY, z, strideZ, fcn, clbk\\[, thisArg] )\n\nApplies a binary function to each pair of elements retrieved from strided input arrays according to a callback function and assigns results to a strided output array.\n\n```javascript\nvar add = require( '@stdlib/number-float64-base-add' );\n\nfunction accessor( values ) {\n    values[ 0 ] *= 2.0;\n    values[ 1 ] *= 2.0;\n    return values;\n}\n\nvar x = [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];\nvar y = [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0, 4.0, 4.0 ];\nvar z = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];\n\nmapBy2( x.length, x, 1, y, 1, z, 1, add, accessor );\n// z =\u003e [ -2.0, 4.0, 10.0, -6.0, 14.0, 6.0, 6.0, 2.0 ]\n```\n\nThe function accepts the following arguments:\n\n-   **N**: number of indexed elements.\n-   **x**: input [`Array`][mdn-array], [`typed array`][mdn-typed-array], or an array-like object (excluding strings and functions).\n-   **strideX**: index increment for `x`.\n-   **y**: input [`Array`][mdn-array], [`typed array`][mdn-typed-array], or an array-like object (excluding strings and functions).\n-   **strideY**: index increment for `y`.\n-   **z**: output [`Array`][mdn-array], [`typed array`][mdn-typed-array], or an array-like object (excluding strings and functions).\n-   **strideZ**: index increment for `z`.\n-   **fcn**: binary function to apply to callback return values.\n-   **clbk**: callback function which returns an array-like object containing two values.\n-   **thisArg**: execution context (_optional_).\n\nThe invoked callback function is provided four arguments:\n\n-   **values**: input array element values `[vx, vy]`.\n-   **idx**: iteration index (zero-based).\n-   **indices**: input and output array strided indices `[ix, iy, iz]` (computed according to `offset + idx*stride`).\n-   **arrays**: input and output arrays/collections `[x, y, z]`.\n\nTo set the callback execution context, provide a `thisArg`.\n\n```javascript\nvar add = require( '@stdlib/number-float64-base-add' );\n\nfunction accessor( values ) {\n    this.count += 1;\n    values[ 0 ] *= 2.0;\n    values[ 1 ] *= 2.0;\n    return values;\n}\n\nvar context = {\n    'count': 0\n};\n\nvar x = [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];\nvar y = [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0, 4.0, 4.0 ];\nvar z = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];\n\nmapBy2( x.length, x, 1, y, 1, z, 1, add, accessor, context );\n// z =\u003e [ -2.0, 4.0, 10.0, -6.0, 14.0, 6.0, 6.0, 2.0 ]\n\nvar cnt = context.count;\n// returns 8\n```\n\nThe `N` and `stride` parameters determine which elements in the strided arrays are accessed at runtime. For example, to index every other value in `x` and to index the first `N` elements of `y` in reverse order,\n\n```javascript\nvar add = require( '@stdlib/number-float64-base-add' );\n\nfunction accessor( values ) {\n    values[ 0 ] *= 2.0;\n    values[ 1 ] *= 2.0;\n    return values;\n}\n\nvar x = [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ];\nvar y = [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0 ];\nvar z = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];\n\nmapBy2( 3, x, 2, y, -1, z, 1, add, accessor );\n// z =\u003e [ 2.0, -4.0, -8.0, 0.0, 0.0, 0.0 ]\n```\n\nNote that indexing is relative to the first index. To introduce an offset, use [`typed array`][mdn-typed-array] views.\n\n```javascript\nvar Float64Array = require( '@stdlib/array-float64' );\nvar add = require( '@stdlib/number-float64-base-add' );\n\nfunction accessor( values ) {\n    values[ 0 ] *= 2.0;\n    values[ 1 ] *= 2.0;\n    return values;\n}\n\n// Initial arrays...\nvar x0 = new Float64Array( [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ] );\nvar y0 = new Float64Array( [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0 ] );\nvar z0 = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );\n\n// Create offset views...\nvar x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element\nvar y1 = new Float64Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element\nvar z1 = new Float64Array( z0.buffer, z0.BYTES_PER_ELEMENT*2 ); // start at 3rd element\n\nmapBy2( 3, x1, -2, y1, 1, z1, 1, add, accessor );\n// z0 =\u003e \u003cFloat64Array\u003e[ 0.0, 0.0, -8.0, -2.0, 2.0, 0.0 ]\n```\n\n#### mapBy2.ndarray( N, x, strideX, offsetX, y, strideY, offsetY, z, strideZ, offsetZ, fcn, clbk\\[, thisArg] )\n\nApplies a binary function to each pair of elements retrieved from strided input arrays according to a callback function and assigns results to a strided output array using alternative indexing semantics.\n\n```javascript\nvar add = require( '@stdlib/number-float64-base-add' );\n\nfunction accessor( values ) {\n    values[ 0 ] *= 2.0;\n    values[ 1 ] *= 2.0;\n    return values;\n}\n\nvar x = [ -1.0, -2.0, -3.0, -4.0, -5.0 ];\nvar y = [ 1.0, 1.0, 2.0, 2.0, 3.0 ];\nvar z = [ 0.0, 0.0, 0.0, 0.0, 0.0 ];\n\nmapBy2.ndarray( x.length, x, 1, 0, y, 1, 0, z, 1, 0, add, accessor );\n// z =\u003e [ 0.0, -2.0, -2.0, -4.0, -4.0 ]\n```\n\nThe function accepts the following additional arguments:\n\n-   **offsetX**: starting index for `x`.\n-   **offsetY**: starting index for `y`.\n-   **offsetZ**: starting index for `z`.\n\nWhile [`typed array`][mdn-typed-array] views mandate a view offset based on the underlying `buffer`, the offset parameters support indexing semantics based on starting indices. For example, to index every other value in `x` starting from the second value and to index the last `N` elements in `y` in reverse order,\n\n```javascript\nvar add = require( '@stdlib/number-float64-base-add' );\n\nfunction accessor( values ) {\n    values[ 0 ] *= 2.0;\n    values[ 1 ] *= 2.0;\n    return values;\n}\n\nvar x = [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ];\nvar y = [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0 ];\nvar z = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];\n\nmapBy2.ndarray( 3, x, 2, 1, y, -1, y.length-1, z, 1, 3, add, accessor );\n// z =\u003e [ 0.0, 0.0, 0.0, 2.0, -2.0, -8.0 ]\n```\n\n\u003c/section\u003e\n\n\u003c!-- /.usage --\u003e\n\n\u003csection class=\"notes\"\u003e\n\n## Notes\n\n-   If a provided callback function does not return any value (or equivalently, explicitly returns `undefined`), the value is **ignored**.\n\n    ```javascript\n    var add = require( '@stdlib/number-float64-base-add' );\n\n    function accessor() {\n        // No-op...\n    }\n\n    var x = [ -2.0, 1.0, 3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ];\n    var y = [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0, 4.0, 4.0 ];\n    var z = [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ];\n\n    mapBy2( x.length, x, 1, y, 1, z, 1, add, accessor );\n    // z =\u003e [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ]\n    ```\n\n\u003c/section\u003e\n\n\u003c!-- /.notes --\u003e\n\n\u003csection class=\"examples\"\u003e\n\n## Examples\n\n\u003c!-- eslint no-undef: \"error\" --\u003e\n\n```javascript\nvar discreteUniform = require( '@stdlib/random-base-discrete-uniform' ).factory;\nvar filledarray = require( '@stdlib/array-filled' );\nvar filledarrayBy = require( '@stdlib/array-filled-by' );\nvar add = require( '@stdlib/number-float64-base-add' );\nvar mapBy2 = require( '@stdlib/strided-base-map-by2' );\n\nfunction accessor( values, i ) {\n    if ( (i%3) === 0 ) {\n        // Simulate a \"missing\" value...\n        return;\n    }\n    return values;\n}\n\nvar x = filledarrayBy( 10, 'generic', discreteUniform( -100, 100 ) );\nconsole.log( x );\n\nvar y = filledarrayBy( 10, 'generic', discreteUniform( -100, 100 ) );\nconsole.log( y );\n\nvar z = filledarray( null, 10, 'generic' );\nconsole.log( z );\n\nmapBy2.ndarray( x.length, x, 1, 0, y, -1, y.length-1, z, 1, 0, add, accessor );\nconsole.log( z );\n```\n\n\u003c/section\u003e\n\n\u003c!-- /.examples --\u003e\n\n\u003c!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. --\u003e\n\n\u003csection class=\"related\"\u003e\n\n* * *\n\n## See Also\n\n-   \u003cspan class=\"package-name\"\u003e[`@stdlib/strided-base/map-by`][@stdlib/strided/base/map-by]\u003c/span\u003e\u003cspan class=\"delimiter\"\u003e: \u003c/span\u003e\u003cspan class=\"description\"\u003eapply a unary function to each element retrieved from a strided input array according to a callback function and assign results to a strided output array.\u003c/span\u003e\n-   \u003cspan class=\"package-name\"\u003e[`@stdlib/strided-base/binary`][@stdlib/strided/base/binary]\u003c/span\u003e\u003cspan class=\"delimiter\"\u003e: \u003c/span\u003e\u003cspan class=\"description\"\u003eapply a binary callback to elements in strided input arrays and assign results to elements in a strided output array.\u003c/span\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.related --\u003e\n\n\u003c!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --\u003e\n\n\n\u003csection class=\"main-repo\" \u003e\n\n* * *\n\n## Notice\n\nThis package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.\n\nFor more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].\n\n#### Community\n\n[![Chat][chat-image]][chat-url]\n\n---\n\n## License\n\nSee [LICENSE][stdlib-license].\n\n\n## Copyright\n\nCopyright \u0026copy; 2016-2026. The Stdlib [Authors][stdlib-authors].\n\n\u003c/section\u003e\n\n\u003c!-- /.stdlib --\u003e\n\n\u003c!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --\u003e\n\n\u003csection class=\"links\"\u003e\n\n[npm-image]: http://img.shields.io/npm/v/@stdlib/strided-base-map-by2.svg\n[npm-url]: https://npmjs.org/package/@stdlib/strided-base-map-by2\n\n[test-image]: https://github.com/stdlib-js/strided-base-map-by2/actions/workflows/test.yml/badge.svg?branch=main\n[test-url]: https://github.com/stdlib-js/strided-base-map-by2/actions/workflows/test.yml?query=branch:main\n\n[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/strided-base-map-by2/main.svg\n[coverage-url]: https://codecov.io/github/stdlib-js/strided-base-map-by2?branch=main\n\n\u003c!--\n\n[dependencies-image]: https://img.shields.io/david/stdlib-js/strided-base-map-by2.svg\n[dependencies-url]: https://david-dm.org/stdlib-js/strided-base-map-by2/main\n\n--\u003e\n\n[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg\n[chat-url]: https://stdlib.zulipchat.com\n\n[stdlib]: https://github.com/stdlib-js/stdlib\n\n[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors\n\n[umd]: https://github.com/umdjs/umd\n[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules\n\n[deno-url]: https://github.com/stdlib-js/strided-base-map-by2/tree/deno\n[deno-readme]: https://github.com/stdlib-js/strided-base-map-by2/blob/deno/README.md\n[umd-url]: https://github.com/stdlib-js/strided-base-map-by2/tree/umd\n[umd-readme]: https://github.com/stdlib-js/strided-base-map-by2/blob/umd/README.md\n[esm-url]: https://github.com/stdlib-js/strided-base-map-by2/tree/esm\n[esm-readme]: https://github.com/stdlib-js/strided-base-map-by2/blob/esm/README.md\n[branches-url]: https://github.com/stdlib-js/strided-base-map-by2/blob/main/branches.md\n\n[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/strided-base-map-by2/main/LICENSE\n\n[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array\n\n[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray\n\n\u003c!-- \u003crelated-links\u003e --\u003e\n\n[@stdlib/strided/base/map-by]: https://github.com/stdlib-js/strided-base-map-by\n\n[@stdlib/strided/base/binary]: https://github.com/stdlib-js/strided-base-binary\n\n\u003c!-- \u003c/related-links\u003e --\u003e\n\n\u003c/section\u003e\n\n\u003c!-- /.links --\u003e\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Fstrided-base-map-by2","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fstdlib-js%2Fstrided-base-map-by2","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Fstrided-base-map-by2/lists"}