{"id":29351100,"url":"https://github.com/stdlib-js/strided-dispatch","last_synced_at":"2025-07-09T00:04:00.978Z","repository":{"id":41465551,"uuid":"377263344","full_name":"stdlib-js/strided-dispatch","owner":"stdlib-js","description":"Create a strided array function interface which performs multiple dispatch.","archived":false,"fork":false,"pushed_at":"2025-02-24T01:35:24.000Z","size":1094,"stargazers_count":2,"open_issues_count":0,"forks_count":0,"subscribers_count":3,"default_branch":"main","last_synced_at":"2025-06-08T23:48:44.379Z","etag":null,"topics":["array","dispatch","javascript","multimethod","multimethods","multiple-dispatch","node","node-js","nodejs","stdlib","strided"],"latest_commit_sha":null,"homepage":"https://github.com/stdlib-js/stdlib","language":"JavaScript","has_issues":false,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"apache-2.0","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/stdlib-js.png","metadata":{"files":{"readme":"README.md","changelog":"CHANGELOG.md","contributing":"CONTRIBUTING.md","funding":null,"license":"LICENSE","code_of_conduct":"CODE_OF_CONDUCT.md","threat_model":null,"audit":null,"citation":"CITATION.cff","codeowners":null,"security":"SECURITY.md","support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null},"funding":{"github":["stdlib-js"],"open_collective":"stdlib","tidelift":"npm/@stdlib/stdlib"}},"created_at":"2021-06-15T18:45:50.000Z","updated_at":"2025-02-24T01:04:34.000Z","dependencies_parsed_at":"2023-10-05T09:19:58.941Z","dependency_job_id":"e30efe7b-59d7-4f3a-8b68-6525804b14e3","html_url":"https://github.com/stdlib-js/strided-dispatch","commit_stats":{"total_commits":57,"total_committers":1,"mean_commits":57.0,"dds":0.0,"last_synced_commit":"9c70d2cb9dba78a82b87ec4ebbc8c3bda702a92d"},"previous_names":[],"tags_count":24,"template":false,"template_full_name":null,"purl":"pkg:github/stdlib-js/strided-dispatch","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fstrided-dispatch","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fstrided-dispatch/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fstrided-dispatch/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fstrided-dispatch/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/stdlib-js","download_url":"https://codeload.github.com/stdlib-js/strided-dispatch/tar.gz/refs/heads/main","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/stdlib-js%2Fstrided-dispatch/sbom","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":264369041,"owners_count":23597324,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","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":["array","dispatch","javascript","multimethod","multimethods","multiple-dispatch","node","node-js","nodejs","stdlib","strided"],"created_at":"2025-07-09T00:01:50.796Z","updated_at":"2025-07-09T00:04:00.967Z","avatar_url":"https://github.com/stdlib-js.png","language":"JavaScript","readme":"\u003c!--\n\n@license Apache-2.0\n\nCopyright (c) 2020 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\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# dispatch\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 Create a strided array function interface which performs multiple dispatch.\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-dispatch\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 dispatch = require( '@stdlib/strided-dispatch' );\n```\n\n#### dispatch( fcns, types, data, nargs, nin, nout )\n\nReturns a strided array function interface which performs multiple dispatch.\n\n\u003c!-- eslint-disable array-element-newline --\u003e\n\n```javascript\nvar unary = require( '@stdlib/strided-base-unary' );\nvar Float64Array = require( '@stdlib/array-float64' );\nvar Float32Array = require( '@stdlib/array-float32' );\n\nfunction foo( x ) {\n    return x * 10.0;\n}\n\nfunction bar( x ) {\n    return x * 5.0;\n}\n\n// Define a list of strided array functions for applying a unary callback:\nvar fcns = [\n    unary,\n    unary\n];\n\n// Define a one-dimensional list of input and output array types:\nvar types = [\n    'float64', 'float64', // input, output\n    'float32', 'float32'  // input, output\n];\n\n// Define a list of callbacks which should be applied based on the provided array types:\nvar data = [\n    foo,\n    bar\n];\n\n// Define the total number of input arguments:\nvar nargs = 7; // N + input_array_dtype + input_array + input_array_stride + output_array_dtype + output_array + output_array_stride\n\n// Define the number of input strided arrays:\nvar nin = 1;\n\n// Define the number of output strided arrays:\nvar nout = 1;\n\n// Create a strided array function interface:\nvar strided = dispatch( fcns, types, data, nargs, nin, nout );\n\n// ...\n\nvar x = new Float64Array( [ 1.0, 2.0, 3.0 ] );\nvar y = new Float64Array( x.length );\n\nstrided( x.length, 'float64', x, 1, 'float64', y, 1 );\n// y =\u003e \u003cFloat64Array\u003e[ 10.0, 20.0, 30.0 ]\n\nx = new Float32Array( [ 1.0, 2.0, 3.0 ] );\ny = new Float32Array( x.length );\n\nstrided( x.length, 'float32', x, 1, 'float32', y, 1 );\n// y =\u003e \u003cFloat32Array\u003e[ 5.0, 10.0, 15.0 ]\n```\n\nThe function accepts the following arguments:\n\n-   **fcns**: list of strided array functions.\n-   **types**: one-dimensional list of strided array argument [data types][@stdlib/strided/dtypes]. The length of `types` must be the number of strided array functions multiplied by `nin+nout`. If `fcns` is a function, rather than a list, the number of strided array functions is computed as `types.length / (nin+nout)`.\n-   **data**: strided array function data (e.g., callbacks). If a list, the length of `data` must equal the number of strided array functions. If `null`, a returned strided array function interface does **not** provide a `data` argument to an invoked strided array function.\n-   **nargs**: total number of strided array function interface arguments (including data types, strides, and offsets).\n-   **nin**: number of input strided arrays.\n-   **nout**: number of output strided arrays.\n\n\u003c/section\u003e\n\n\u003c!-- /.usage --\u003e\n\n\u003csection class=\"notes\"\u003e\n\n## Notes\n\n-   Without offsets, a returned strided array function interface has the following signature:\n\n    ```text\n    f( N, dtypeX, x, strideX, dtypeY, y, strideY, ... )\n    ```\n\n    where\n\n    -   **N**: number of indexed elements.\n    -   **dtypeX**: [data type][@stdlib/strided/dtypes] for `x`.\n    -   **x**: strided array.\n    -   **strideX**: index increment for `x`.\n    -   **dtypeY**: [data type][@stdlib/strided/dtypes] for `y`.\n    -   **y**: strided array.\n    -   **strideY**: index increment for `y`.\n    -   **...**: additional strided arrays and associated [data types][@stdlib/strided/dtypes] and strides.\n\n-   The number of strided array function interface parameters is derived from `nargs`, the number of input strided arrays is derived from `nin`, and the number of output strided arrays is derived from `nout`.\n\n-   Without offsets, the number of parameters must obey the following relation:\n\n    ```text\n    nargs = 3*(nout+nin) + 1\n    ```\n\n-   With offsets, the number of parameters must obey the following relation:\n\n    ```text\n    nargs = 4*(nout+nin) + 1\n    ```\n\n-   With offsets, a returned strided array function interface has the following signature:\n\n    ```text\n    f( N, dtypeX, x, strideX, offsetX, dtypeY, y, strideY, offsetY, ... )\n    ```\n\n    where\n\n    -   **N**: number of indexed elements.\n    -   **dtypeX**: [data type][@stdlib/strided/dtypes] for `x`.\n    -   **x**: strided array.\n    -   **strideX**: index increment for `x`.\n    -   **offsetX**: starting index for `x`.\n    -   **dtypeY**: [data type][@stdlib/strided/dtypes] for `y`.\n    -   **y**: strided array.\n    -   **strideY**: index increment for `y`.\n    -   **offsetY**: starting index for `y`.\n    -   **...**: additional strided arrays and associated [data types][@stdlib/strided/dtypes], strides, and offsets.\n\n    The choice of which strided array function interface to return depends on the use case. The former is suitable for typed array views; while the latter affords alternative indexing semantics more suitable for n-dimensional arrays (ndarrays).\n\n-   Without offsets, a strided array function (i.e., a value provided for the `fcns` argument) should have the following signature:\n\n    ```text\n    f( arrays, shape, strides[, data] )\n    ```\n\n    where\n\n    -   **arrays**: array containing strided input and output arrays.\n    -   **shape**: array containing a single element, the number of indexed elements.\n    -   **strides**: array containing the stride lengths for the strided input and output arrays.\n    -   **data**: strided array function data (e.g., a callback).\n\n-   With offsets, a strided array function should have the following signature:\n\n    ```text\n    f( arrays, shape, strides, offsets[, data] )\n    ```\n\n    where\n\n    -   **offsets**: array containing the starting indices (i.e., index offsets) for the strided input and output arrays.\n\n-   For convenience, a single strided array function may be provided which will be invoked whenever the strided array argument data types match a sequence of types in `types`. Providing a single strided array function is particularly convenient for the case where, regardless of array data types, traversing arrays remains the same, but the strided array function `data` differs (e.g., callbacks which differ based on the array data types). For example, the following\n\n    \u003c!-- eslint-disable array-element-newline --\u003e\n\n    ```javascript\n    var unary = require( '@stdlib/strided-base-unary' );\n\n    function foo( x ) {\n        return x * 10.0;\n    }\n\n    function bar( x ) {\n        return x * 5.0;\n    }\n\n    var fcns = [\n        unary,\n        unary\n    ];\n    var types = [\n        'float64', 'float64',\n        'float32', 'float32'\n    ];\n    var data = [\n        foo,\n        bar\n    ];\n\n    var strided = dispatch( fcns, types, data, 7, 1, 1 );\n    ```\n\n    is equivalent to\n\n    \u003c!-- eslint-disable array-element-newline --\u003e\n\n    ```javascript\n    var unary = require( '@stdlib/strided-base-unary' );\n\n    function foo( x ) {\n        return x * 10.0;\n    }\n\n    function bar( x ) {\n        return x * 5.0;\n    }\n\n    var types = [\n        'float64', 'float64',\n        'float32', 'float32'\n    ];\n    var data = [\n        foo,\n        bar\n    ];\n\n    var strided = dispatch( unary, types, data, 7, 1, 1 );\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 unary = require( '@stdlib/strided-base-unary' ).ndarray;\nvar abs = require( '@stdlib/math-base-special-abs' );\nvar Float64Array = require( '@stdlib/array-float64' );\nvar dispatch = require( '@stdlib/strided-dispatch' );\n\nvar types = [ 'float64', 'float64' ];\n\nvar data = [\n    abs\n];\n\nvar strided = dispatch( unary, types, data, 9, 1, 1 );\n\nvar x = new Float64Array( [ -1.0, -2.0, -3.0, -4.0, -5.0 ] );\nvar y = new Float64Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );\n\nstrided( 3, 'float64', x, 1, 2, 'float64', y, 1, 2 );\nconsole.log( y );\n// =\u003e \u003cFloat64Array\u003e[ 0.0, 0.0, 3.0, 4.0, 5.0 ]\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\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; 2016-2025. 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-dispatch.svg\n[npm-url]: https://npmjs.org/package/@stdlib/strided-dispatch\n\n[test-image]: https://github.com/stdlib-js/strided-dispatch/actions/workflows/test.yml/badge.svg?branch=main\n[test-url]: https://github.com/stdlib-js/strided-dispatch/actions/workflows/test.yml?query=branch:main\n\n[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/strided-dispatch/main.svg\n[coverage-url]: https://codecov.io/github/stdlib-js/strided-dispatch?branch=main\n\n\u003c!--\n\n[dependencies-image]: https://img.shields.io/david/stdlib-js/strided-dispatch.svg\n[dependencies-url]: https://david-dm.org/stdlib-js/strided-dispatch/main\n\n--\u003e\n\n[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg\n[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im\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-dispatch/tree/deno\n[deno-readme]: https://github.com/stdlib-js/strided-dispatch/blob/deno/README.md\n[umd-url]: https://github.com/stdlib-js/strided-dispatch/tree/umd\n[umd-readme]: https://github.com/stdlib-js/strided-dispatch/blob/umd/README.md\n[esm-url]: https://github.com/stdlib-js/strided-dispatch/tree/esm\n[esm-readme]: https://github.com/stdlib-js/strided-dispatch/blob/esm/README.md\n[branches-url]: https://github.com/stdlib-js/strided-dispatch/blob/main/branches.md\n\n[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/strided-dispatch/main/LICENSE\n\n[@stdlib/strided/dtypes]: https://github.com/stdlib-js/strided-dtypes\n\n\u003c/section\u003e\n\n\u003c!-- /.links --\u003e\n","funding_links":["https://github.com/sponsors/stdlib-js","https://opencollective.com/stdlib","https://tidelift.com/funding/github/npm/@stdlib/stdlib"],"categories":[],"sub_categories":[],"project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Fstrided-dispatch","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fstdlib-js%2Fstrided-dispatch","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fstdlib-js%2Fstrided-dispatch/lists"}