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https://github.com/stdlib-js/ndarray-base-min-view-buffer-index

Compute the minimum linear index in an underlying data buffer accessible to an array view.
https://github.com/stdlib-js/ndarray-base-min-view-buffer-index

array base idx index javascript linear min minimum multidimensional ndarray node node-js nodejs stdlib strides types utilities utility utils view

Last synced: 25 days ago
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Compute the minimum linear index in an underlying data buffer accessible to an array view.

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README 

        



  

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# minViewBufferIndex



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



> Compute the minimum linear index in an underlying data buffer accessible to an array view.



## Installation



```bash

npm install @stdlib/ndarray-base-min-view-buffer-index

```



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 minViewBufferIndex = require( '@stdlib/ndarray-base-min-view-buffer-index' );

```



#### minViewBufferIndex( shape, strides, offset )



Computes the minimum linear index in an underlying data buffer accessible to an array view.



```javascript

// Array shape:

var shape = [ 2, 2 ];



// Stride array:

var strides = [ -2, -1 ];



// Index offset which specifies the location of the first indexed value:

var offset = 13; // includes a view offset



var idx = minViewBufferIndex( shape, strides, offset );

// returns 10

```



## Examples



```javascript

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );

var shape2strides = require( '@stdlib/ndarray-base-shape2strides' );

var strides2offset = require( '@stdlib/ndarray-base-strides2offset' );

var randu = require( '@stdlib/random-base-randu' );

var minViewBufferIndex = require( '@stdlib/ndarray-base-min-view-buffer-index' );



var strides;

var offset;

var shape;

var idx;

var i;

var j;



shape = [ 0, 0, 0 ];



for ( i = 0; i < 100; i++ ) {

    // Generate a random array shape:

    shape[ 0 ] = discreteUniform( 1, 10 );

    shape[ 1 ] = discreteUniform( 1, 10 );

    shape[ 2 ] = discreteUniform( 1, 10 );



    // Generate strides:

    if ( randu() < 0.5 ) {

        strides = shape2strides( shape, 'row-major' );

    } else {

        strides = shape2strides( shape, 'column-major' );

    }

    j = discreteUniform( 0, shape.length-1 );

    strides[ j ] *= ( randu() < 0.5 ) ? -1 : 1;



    // Compute the index offset:

    offset = strides2offset( shape, strides ) + 25; // include view offset



    // Compute the minimum linear index:

    idx = minViewBufferIndex( shape, strides, offset );

    console.log( 'Shape: %s. Strides: %s. Offset: %d. Min idx: %d.', shape.join( 'x' ), strides.join( ',' ), offset, idx );

}

```



* * *



## C APIs



### Usage



```c

#include "stdlib/ndarray/base/min_view_buffer_index.h"

```



#### stdlib_ndarray_min_view_buffer_index( ndims, \*shape, \*strides, offset )



Computes the minimum linear index (in bytes) in an underlying data buffer accessible to an array view.



```c

#include 



int64_t ndims = 2;

int64_t shape[] = { 10, 10 };

int64_t strides[] = { 10, 1 };

int64_t offset = 10;



int64_t idx = stdlib_ndarray_min_view_buffer_index( ndims, shape, strides, offset );

// returns 10

```



The function accepts the following arguments:



-   **ndims**: `[in] int64_t` number of dimensions.

-   **shape**: `[in] int64_t*` array shape (dimensions).

-   **strides**: `[in] int64_t*` array strides (in bytes).

-   **offset**: `[in] int64_t` index offset.



```c

int64_t stdlib_ndarray_min_view_buffer_index( const int64_t ndims, const int64_t *shape, const int64_t *strides, const int64_t offset );

```



### Examples



```c

#include "stdlib/ndarray/base/min_view_buffer_index.h"

#include 

#include 

#include 



int main( void ) {

    // Specify the number of dimensions:

    const int64_t ndims = 2;



    // Define an array shape:

    const int64_t shape[] = { 10, 10 };



    // Define array strides:

    const int64_t strides[] = { -2, 5 };



    // Define an offset:

    const int64_t offset = 100;



    // Compute the minimum accessible index:

    int64_t idx = stdlib_ndarray_min_view_buffer_index( ndims, shape, strides, offset );



    // Print the results:

    printf( "idx: %"PRId64"\n", idx );

}

```



* * *



## 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-min-view-buffer-index.svg

[npm-url]: https://npmjs.org/package/@stdlib/ndarray-base-min-view-buffer-index



[test-image]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/actions/workflows/test.yml/badge.svg?branch=main

[test-url]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/actions/workflows/test.yml?query=branch:main



[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/ndarray-base-min-view-buffer-index/main.svg

[coverage-url]: https://codecov.io/github/stdlib-js/ndarray-base-min-view-buffer-index?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-min-view-buffer-index/tree/deno

[deno-readme]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/tree/umd

[umd-readme]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/tree/esm

[esm-readme]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/ndarray-base-min-view-buffer-index/blob/main/branches.md



[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/ndarray-base-min-view-buffer-index/main/LICENSE