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https://github.com/stdlib-js/ndarray-base-serialize-meta-data

Serialize ndarray meta data.
https://github.com/stdlib-js/ndarray-base-serialize-meta-data

array base javascript meta multidimensional ndarray node node-js nodejs protocol serialization serialize stdlib types util utilities utility utils

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Serialize ndarray meta data.

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README 

        



  

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# Serialize Meta Data



[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] 



> Serialize [ndarray][@stdlib/ndarray/ctor] meta data.



## Installation



```bash

npm install @stdlib/ndarray-base-serialize-meta-data

```



Alternatively,



-   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]).

-   If you are using Deno, visit the [`deno`][deno-url] branch (see [README][deno-readme] for usage intructions).

-   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]).



The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.



To 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.



## Usage



```javascript

var serialize = require( '@stdlib/ndarray-base-serialize-meta-data' );

```



#### serialize( x )



Serializes [ndarray][@stdlib/ndarray/ctor] meta data.



```javascript

var array = require( '@stdlib/ndarray-array' );



var arr = array( [ [ 1, 2 ], [ 3, 4 ] ] );

var dv = serialize( arr );

// returns 

```



## Notes



-   Serialization is performed according to host byte order (endianness).



-   Meta data format:



    ```text

    | endianness (1 byte) |  (2 bytes) |  (8 bytes) |  (ndims*8 bytes) |  (ndims*8 bytes) |  (8 bytes) |  (1 byte) |  (1 byte) |  (8 bytes) |  (nsubmodes*1 bytes) |  (4 bytes) |

    ```



    which translates to the following `ArrayBuffer` layout:



    ```text

    ArrayBuffer[

        [int8],

        [int16],

        [int64],

        [ndims*int64],

        [ndims*int64],

        [int64],

        [int8],

        [int8],

        [int64],

        [nsubmodes*int8],

        [int32]

    ]

    ```



    where `strides` and `offset` are in units of bytes.



-   If the endianness is `1`, the byte order is little endian. If the endianness is `0`, the byte order is big endian.



-   Buffer length:



    ```text

    1 + 2 + 8 + (ndims*8) + (ndims*8) + 8 + 1 + 1 + 8 + (nsubmodes*1) + 4 = 33 + (ndims*16) + nsubmodes

    ```



    For example, consider a three-dimensional [ndarray][@stdlib/ndarray/ctor] with one subscript index mode (submode):



    ```text

    33 + (3*16) + 1 = 82 bytes

    ```



## Examples



```javascript

var IS_LITTLE_ENDIAN = require( '@stdlib/assert-is-little-endian' );

var array = require( '@stdlib/ndarray-array' );

var Uint8Array = require( '@stdlib/array-uint8' );

var fromInt64Bytes = require( '@stdlib/number-float64-base-from-int64-bytes' );

var serialize = require( '@stdlib/ndarray-base-serialize-meta-data' );



// Create an ndarray:

var x = array( [ [ 1, 2 ], [ 3, 4 ] ] );



// Print various properties:

console.log( 'dtype: %s', x.dtype );

console.log( 'ndims: %d', x.ndims );

console.log( 'shape: [ %s ]', x.shape.join( ', ' ) );

console.log( 'strides: [ %s ]', x.strides.join( ', ' ) );

console.log( 'offset: %d', x.offset );

console.log( 'order: %s', x.order );



// Serialize ndarray meta data to a DataView:

var dv = serialize( x );

// returns 



// Create a Uint8Array view:

var bytes = new Uint8Array( dv.buffer );



// Extract the data type (enum):

var dtype = dv.getInt16( 1, IS_LITTLE_ENDIAN );

console.log( 'dtype (enum): %d', dtype );



// Extract the number of dimensions:

var ndims = fromInt64Bytes( bytes, 1, 3 );

console.log( 'ndims: %d', ndims );



// Extract the shape:

var shape = [];

var i;

for ( i = 0; i < ndims; i++ ) {

    shape.push( fromInt64Bytes( bytes, 1, 11+(i*8) ) );

}

console.log( 'shape: [ %s ]', shape.join( ', ' ) );



// Extract the strides (in units of bytes):

var strides = [];

for ( i = 0; i < ndims; i++ ) {

    strides.push( fromInt64Bytes( bytes, 1, 11+(ndims*8)+(i*8) ) );

}

console.log( 'strides (bytes): [ %s ]', strides.join( ', ' ) );



// Extract the index offset (in bytes):

var offset = fromInt64Bytes( bytes, 1, 11+(ndims*16) );

console.log( 'offset (bytes): %d', offset );



// Extract the order (enum):

var order = dv.getInt8( 19+(ndims*16) );

console.log( 'order (enum): %d', order );

```



* * *



## Notice



This 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.



For 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].



#### Community



[![Chat][chat-image]][chat-url]



---



## License



See [LICENSE][stdlib-license].



## Copyright



Copyright © 2016-2024. The Stdlib [Authors][stdlib-authors].



[npm-image]: http://img.shields.io/npm/v/@stdlib/ndarray-base-serialize-meta-data.svg

[npm-url]: https://npmjs.org/package/@stdlib/ndarray-base-serialize-meta-data



[test-image]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/actions/workflows/test.yml/badge.svg?branch=main

[test-url]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/actions/workflows/test.yml?query=branch:main



[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-base-serialize-meta-data/main.svg

[coverage-url]: https://codecov.io/github/stdlib-js/ndarray-base-serialize-meta-data?branch=main



[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg

[chat-url]: https://app.gitter.im/#/room/#stdlib-js_stdlib:gitter.im



[stdlib]: https://github.com/stdlib-js/stdlib



[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors



[umd]: https://github.com/umdjs/umd

[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules



[deno-url]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/tree/deno

[deno-readme]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/tree/umd

[umd-readme]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/tree/esm

[esm-readme]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/ndarray-base-serialize-meta-data/blob/main/branches.md



[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-base-serialize-meta-data/main/LICENSE



[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray-ctor