npm package: @stdlib/number-float64-base-exponent
Description: Return an integer corresponding to the unbiased exponent of a double-precision floating-point number.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    About stdlib...
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# exponent

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

> Return an integer corresponding to the unbiased exponent of a [double-precision floating-point number][ieee754].

<section class="installation">

## Installation

```bash
npm install @stdlib/number-float64-base-exponent
```

</section>

<section class="usage">

## Usage

```javascript
var exponent = require( '@stdlib/number-float64-base-exponent' );
```

#### exponent( x )

Returns an `integer` corresponding to the unbiased exponent of a [double-precision floating-point number][ieee754].

```javascript
var exp = exponent( 3.14e307 ); // => 2**1021 ~ 1e307
// returns 1021

exp = exponent( 3.14e-307 ); // => 2**-1019 ~ 1e-307
// returns -1019

exp = exponent( -3.14 );
// returns 1

exp = exponent( 0.0 );
// returns -1023

exp = exponent( NaN );
// returns 1024
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random-base-uniform' );
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var pow = require( '@stdlib/math-base-special-pow' );
var exponent = require( '@stdlib/number-float64-base-exponent' );

var frac;
var exp;
var x;
var e;
var i;

// Generate random numbers and extract their exponents...
for ( i = 0; i < 100; i++ ) {
    frac = randu( 0.0, 10.0 );
    exp = discreteUniform( -323, 323 );
    x = frac * pow( 10.0, exp );
    e = exponent( x );
    console.log( 'x: %d. unbiased exponent: %d.', x, e );
}
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- C usage documentation. -->

<section class="usage">

### Usage

```c
#include "stdlib/number/float64/base/exponent.h"
```

#### stdlib_base_float64_exponent( x )

Returns an integer corresponding to the unbiased exponent of a [double-precision floating-point number][ieee754].

```c
#include <stdint.h>

int32_t out = stdlib_base_float64_exponent( 3.14 );
```

The function accepts the following arguments:

-   **x**: `[in] double` input value.

```c
int32_t stdlib_base_float64_exponent( const double x );
```

</section>

<!-- /.usage -->

<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

</section>

<!-- /.notes -->

<!-- C API usage examples. -->

<section class="examples">

### Examples

```c
#include "stdlib/number/float64/base/exponent.h"
#include <stdint.h>
#include <stdio.h>
#include <inttypes.h>

int main( void ) {
    double x[] = { 4.0, 0.0, -0.0, 1.0, -1.0, 3.14, -3.14, 1.0e308, -1.0e308, 1.0/0.0, -1.0/0.0, 0.0/0.0 };

    int32_t out;
    int i;
    for ( i = 0; i < 12; i++ ) {
        out = stdlib_base_float64_exponent( x[ i ] );
        printf( "%lf => out: %" PRId32 "\n", x[ i ], out );
    }
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/number-float32/base/exponent`][@stdlib/number/float32/base/exponent]</span><span class="delimiter">: </span><span class="description">return an integer corresponding to the unbiased exponent of a single-precision floating-point number.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<section class="main-repo" >

* * *

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

</section>

<!-- /.stdlib -->

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[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/number-float64-base-exponent/tree/deno
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/number-float64-base-exponent/main/LICENSE

[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985

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[@stdlib/number/float32/base/exponent]: https://www.npmjs.com/package/@stdlib/number-float32-base-exponent

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</section>

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