https://github.com/stdlib-js/strided-base-smskmap2

Apply a binary function to single-precision floating-point strided input arrays according to a strided mask array and assign results to a single-precision floating-point strided output array.
https://github.com/stdlib-js/strided-base-smskmap2

apply array base binary float float32 flt foreach javascript map mask masked ndarray node node-js nodejs single-precision stdlib strided transform

Last synced: 3 days ago
JSON representation

Apply a binary function to single-precision floating-point strided input arrays according to a strided mask array and assign results to a single-precision floating-point strided output array.

Host: GitHub
URL: https://github.com/stdlib-js/strided-base-smskmap2
Owner: stdlib-js
License: apache-2.0
Created: 2021-10-27T23:25:58.000Z (over 4 years ago)
Default Branch: main
Last Pushed: 2026-05-24T03:41:28.000Z (about 1 month ago)
Last Synced: 2026-06-06T19:32:06.158Z (22 days ago)
Topics: apply, array, base, binary, float, float32, flt, foreach, javascript, map, mask, masked, ndarray, node, node-js, nodejs, single-precision, stdlib, strided, transform
Language: JavaScript
Homepage: https://github.com/stdlib-js/stdlib
Size: 584 KB
Stars: 2
Watchers: 2
Forks: 0
Open Issues: 0
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
- Notice: NOTICE

Awesome Lists containing this project

README

          

  

    About stdlib...

  

  
We 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.

  The 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.

  When 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.

  To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!


# smskmap2

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

> Apply a binary function to single-precision floating-point strided input arrays according to a strided mask array and assign results to a single-precision floating-point strided output array.

## Installation

```bash

npm install @stdlib/strided-base-smskmap2

```

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 smskmap2 = require( '@stdlib/strided-base-smskmap2' );

```

#### smskmap2( N, x, strideX, y, strideY, mask, strideMask, z, strideZ, fcn )

Applies a binary function to single-precision floating-point strided input arrays according to a strided mask array and assigns results to a single-precision floating-point strided output array.

```javascript

var Float32Array = require( '@stdlib/array-float32' );

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

var addf = require( '@stdlib/number-float32-base-add' );

var x = new Float32Array( [ -2.0, 1.0, -3.0, -5.0, 4.0, 0.0, -1.0, -3.0 ] );

var y = new Float32Array( [ 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0 ] );

var z = new Float32Array( x.length );

var m = new Uint8Array( [ 0, 0, 1, 0, 0, 1, 1, 0 ] );

smskmap2( x.length, x, 1, y, 1, m, 1, z, 1, addf );

// z => [ -1.0, 3.0, 0.0, -1.0, 9.0, 0.0, 0.0, 5.0 ]

```

The function accepts the following arguments:

-   **N**: number of indexed elements.

-   **x**: input [`Float32Array`][@stdlib/array/float32].

-   **strideX**: index increment for `x`.

-   **y**: input [`Float32Array`][@stdlib/array/float32].

-   **strideY**: index increment for `y`.

-   **mask**: mask [`Uint8Array`][@stdlib/array/uint8].

-   **strideMask**: index increment for `mask`.

-   **z**: output [`Float32Array`][@stdlib/array/float32].

-   **strideZ**: index increment for `z`.

-   **fcn**: function to apply.

The `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,

```javascript

var Float32Array = require( '@stdlib/array-float32' );

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

var addf = require( '@stdlib/number-float32-base-add' );

var x = new Float32Array( [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ] );

var y = new Float32Array( [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0 ] );

var z = new Float32Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

var m = new Uint8Array( [ 0, 0, 1, 0, 0, 1 ] );

smskmap2( 3, x, 2, y, -1, m, 2, z, 1, addf );

// z => [ 1.0, 0.0, -4.0, 0.0, 0.0, 0.0 ]

```

Note that indexing is relative to the first index. To introduce an offset, use [`typed array`][@stdlib/array/float32] views.

```javascript

var Float32Array = require( '@stdlib/array-float32' );

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

var addf = require( '@stdlib/number-float32-base-add' );

// Initial arrays...

var x0 = new Float32Array( [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ] );

var y0 = new Float32Array( [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0 ] );

var z0 = new Float32Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

var m0 = new Uint8Array( [ 0, 0, 1, 0, 0, 1 ] );

// Create offset views...

var x1 = new Float32Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element

var y1 = new Float32Array( y0.buffer, y0.BYTES_PER_ELEMENT*3 ); // start at 4th element

var z1 = new Float32Array( z0.buffer, z0.BYTES_PER_ELEMENT*2 ); // start at 3rd element

var m1 = new Uint8Array( m0.buffer, m0.BYTES_PER_ELEMENT*3 ); // start at 4th element

smskmap2( 3, x1, -2, y1, 1, m1, 1, z1, 1, addf );

// z0 => [ 0.0, 0.0, -4.0, -1.0, 0.0, 0.0 ]

```

#### smskmap2.ndarray( N, x, strideX, offsetX, y, strideY, offsetY, mask, strideMask, offsetMask, z, strideZ, offsetZ, fcn )

Applies a binary function to single-precision floating-point strided input arrays according to a strided mask array and assigns results to a single-precision floating-point strided output array using alternative indexing semantics.

```javascript

var Float32Array = require( '@stdlib/array-float32' );

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

var addf = require( '@stdlib/number-float32-base-add' );

var x = new Float32Array( [ -1.0, -2.0, -3.0, -4.0, -5.0 ] );

var y = new Float32Array( [ 1.0, 1.0, 2.0, 2.0, 3.0 ] );

var z = new Float32Array( [ 0.0, 0.0, 0.0, 0.0, 0.0 ] );

var m = new Uint8Array( [ 0, 0, 1, 0, 0 ] );

smskmap2.ndarray( x.length, x, 1, 0, y, 1, 0, m, 1, 0, z, 1, 0, addf );

// z => [ 0.0, -1.0, 0.0, -2.0, -2.0 ]

```

The function accepts the following addfitional arguments:

-   **offsetX**: starting index for `x`.

-   **offsetY**: starting index for `y`.

-   **offsetMask**: starting index for `mask`.

-   **offsetZ**: starting index for `z`.

While [`typed array`][@stdlib/array/float32] 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,

```javascript

var Float32Array = require( '@stdlib/array-float32' );

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

var addf = require( '@stdlib/number-float32-base-add' );

var x = new Float32Array( [ -1.0, -2.0, -3.0, -4.0, -5.0, -6.0 ] );

var y = new Float32Array( [ 1.0, 1.0, 2.0, 2.0, 3.0, 3.0 ] );

var z = new Float32Array( [ 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 ] );

var m = new Uint8Array( [ 0, 0, 1, 0, 0, 1 ] );

smskmap2.ndarray( 3, x, 2, 1, y, -1, y.length-1, m, 2, 1, z, 1, 0, addf );

// z => [ 1.0, -1.0, 0.0, 0.0, 0.0, 0.0 ]

```

## Examples

```javascript

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

var bernoulli = require( '@stdlib/random-base-bernoulli' ).factory;

var Float32Array = require( '@stdlib/array-float32' );

var filledarrayBy = require( '@stdlib/array-filled-by' );

var addf = require( '@stdlib/number-float32-base-add' );

var smskmap2 = require( '@stdlib/strided-base-smskmap2' );

var x = filledarrayBy( 10, 'float32', discreteUniform( -100, 100 ) );

console.log( x );

var y = filledarrayBy( x.length, 'float32', discreteUniform( -100, 100 ) );

console.log( y );

var m = filledarrayBy( x.length, 'uint8', bernoulli( 0.2 ) );

console.log( m );

var z = new Float32Array( x.length );

console.log( z );

smskmap2.ndarray( x.length, x, 1, 0, y, -1, y.length-1, m, 1, 0, z, 1, 0, addf );

console.log( z );

```

* * *

## C APIs

### Usage

```c

#include "stdlib/strided/base/smskmap2.h"

```

#### stdlib_strided_smskmap2( N, \*X, strideX, \*Y, strideY, \*Mask, strideMask, \*Z, strideZ, fcn )

Applies a binary function to single-precision floating-point strided input arrays according to a strided mask array and assigns results to a single-precision floating-point strided output array.

```c

#include 

static float addf( const float x, const float y ) {

    return x + y;

}

float X[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f };

float Y[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f };

float Z[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

uint8_t M[] = { 0, 0, 1, 0, 0, 1 };

int64_t N = 6;

stdlib_strided_smskmap2( N, X, 1, Y, 1, M, 1, Z, 1, addf );

```

The function accepts the following arguments:

-   **N**: `[in] int64_t` number of indexed elements.

-   **X**: `[in] float*` input array.

-   **strideX** `[in] int64_t` index increment for `X`.

-   **Y**: `[int] float*` input array.

-   **strideY**: `[in] int64_t` index increment for `Y`.

-   **Mask**: `[in] uint8_t*` mask array.

-   **strideMask**: `[in] int64_t` index increment for `Mask`.

-   **Z**: `[out] float*` output array.

-   **strideZ**: `[in] int64_t` index increment for `Z`.

-   **fcn**: `[in] float (*fcn)( float, float )` binary function to apply.

```c

void stdlib_strided_smskmap2( const int64_t N, const float *X, const int64_t strideX, const float *Y, const int64_t strideY, const uint8_t *Mask, const int64_t strideMask, float *Z, const int64_t strideZ, float (*fcn)( float, float ) );

```

### Examples

```c

#include "stdlib/strided/base/smskmap2.h"

#include 

#include 

#include 

// Define a callback:

static float addf( const float x, const float y ) {

    return x + y;

}

int main( void ) {

    // Create input strided arrays:

    float X[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f };

    float Y[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f };

    // Create a mask strided array:

    uint8_t M[] = { 0, 0, 1, 0, 0, 1 };

    // Create an output strided array:

    float Z[] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };

    // Specify the number of elements:

    int64_t N = 6;

    // Define the strides:

    int64_t strideX = 1;

    int64_t strideY = -1;

    int64_t strideZ = 1;

    int64_t strideM = 1;

    // Apply the callback:

    stdlib_strided_smskmap2( N, X, strideX, Y, strideY, M, strideM, Z, strideZ, addf );

    // Print the results:

    for ( int64_t i = 0; i < N; i++ ) {

        printf( "Z[ %"PRId64" ] = %f\n", i, Z[ i ] );

    }

}

```

* * *

## See Also

-   [`@stdlib/strided-base/dmskmap2`][@stdlib/strided/base/dmskmap2]: apply a binary function to double-precision floating-point strided input arrays according to a strided mask array and assign results to a double-precision floating-point strided output array.

-   [`@stdlib/strided-base/smap2`][@stdlib/strided/base/smap2]: apply a binary function to single-precision floating-point strided input arrays and assign results to a single-precision floating-point strided output array.

-   [`@stdlib/strided-base/smskmap`][@stdlib/strided/base/smskmap]: apply a unary function to a single-precision floating-point strided input array according to a strided mask array and assign results to a single-precision floating-point strided output array.

* * *

## 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 © 2016-2026. The Stdlib [Authors][stdlib-authors].

[npm-image]: http://img.shields.io/npm/v/@stdlib/strided-base-smskmap2.svg

[npm-url]: https://npmjs.org/package/@stdlib/strided-base-smskmap2

[test-image]: https://github.com/stdlib-js/strided-base-smskmap2/actions/workflows/test.yml/badge.svg?branch=main

[test-url]: https://github.com/stdlib-js/strided-base-smskmap2/actions/workflows/test.yml?query=branch:main

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/strided-base-smskmap2/main.svg

[coverage-url]: https://codecov.io/github/stdlib-js/strided-base-smskmap2?branch=main

[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg

[chat-url]: https://stdlib.zulipchat.com

[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/strided-base-smskmap2/tree/deno

[deno-readme]: https://github.com/stdlib-js/strided-base-smskmap2/blob/deno/README.md

[umd-url]: https://github.com/stdlib-js/strided-base-smskmap2/tree/umd

[umd-readme]: https://github.com/stdlib-js/strided-base-smskmap2/blob/umd/README.md

[esm-url]: https://github.com/stdlib-js/strided-base-smskmap2/tree/esm

[esm-readme]: https://github.com/stdlib-js/strided-base-smskmap2/blob/esm/README.md

[branches-url]: https://github.com/stdlib-js/strided-base-smskmap2/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/strided-base-smskmap2/main/LICENSE

[@stdlib/array/float32]: https://github.com/stdlib-js/array-float32

[@stdlib/array/uint8]: https://github.com/stdlib-js/array-uint8

[@stdlib/strided/base/dmskmap2]: https://github.com/stdlib-js/strided-base-dmskmap2

[@stdlib/strided/base/smap2]: https://github.com/stdlib-js/strided-base-smap2

[@stdlib/strided/base/smskmap]: https://github.com/stdlib-js/strided-base-smskmap

ecosyste.ms

Data

Tools

Indexes

Applications

Experiments

Awesome

https://github.com/stdlib-js/strided-base-smskmap2

Awesome Lists containing this project

README