npm package: @stdlib/ndarray-base-binary-input-casting-dtype
Description: Resolve the casting data type for an input ndarray provided to a binary function.
Author: The Stdlib Authors
Latest version: 0.1.1

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# binaryInputCastingDataType

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> Resolve the casting [data type][@stdlib/ndarray/dtypes] for an input ndarray provided to a binary function.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-base-binary-input-casting-dtype
```

</section>

<section class="usage">

## Usage

<!-- eslint-disable id-length -->

```javascript
var binaryInputCastingDataType = require( '@stdlib/ndarray-base-binary-input-casting-dtype' );
```

#### binaryInputCastingDataType( idtype1, idtype2, odtype, policy )

Resolves the casting [data type][@stdlib/ndarray/dtypes] for an input ndarray provided to a binary function according to a [data type policy][@stdlib/ndarray/input-casting-policies].

<!-- eslint-disable id-length -->

```javascript
var dt = binaryInputCastingDataType( 'int32', 'int32', 'float64', 'promoted' );
// returns 'float64'
```

The function supports the following parameters:

-   **idtype1**: input ndarray data type.
-   **idtype2**: additional input ndarray data type.
-   **odtype**: output ndarray data type.
-   **policy**: input ndarray [casting policy][@stdlib/ndarray/input-casting-policies].

If `policy` is a [data type][@stdlib/ndarray/dtypes], the function always returns the `policy` value (i.e., the fourth argument).

<!-- eslint-disable id-length -->

```javascript
var dt = binaryInputCastingDataType( 'float32', 'float32', 'float64', 'complex128' );
// returns 'complex128'

dt = binaryInputCastingDataType( 'int32', 'float64', 'float64', 'complex128' );
// returns 'complex128'

// ...
```

</section>

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<section class="notes">

</section>

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<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var naryFunction = require( '@stdlib/utils-nary-function' );
var unzip = require( '@stdlib/utils-unzip' );
var nCartesianProduct = require( '@stdlib/array-base-n-cartesian-product' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var inputCastingDataType = require( '@stdlib/ndarray-base-binary-input-casting-dtype' );

var idt1 = [
    'float32',
    'float64'
];

var idt2 = [
    'int8',
    'uint8',
    'uint16',
    'uint32'
];

var odt = [
    'float32',
    'float64',
    'complex64',
    'complex128'
];

// Define a list of casting policies:
var policies = [
    'promoted',
    'accumulation',
    'output'
];

// Generate dtype-policy argument groups:
var args = nCartesianProduct( idt1, idt2, odt, policies );

// Unzip the argument arrays:
args = unzip( args );

// Resolve casting data types:
logEachMap( 'dtypes: (%10s, %10s, %10s). policy: %20s. result: %10s.', args[ 0 ], args[ 1 ], args[ 2 ], args[ 3 ], naryFunction( inputCastingDataType, 4 ) );
```

</section>

<!-- /.examples -->

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* * *

## 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.

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## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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