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214 changes: 214 additions & 0 deletions lib/node_modules/@stdlib/number/uint32/base/identity/README.md
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<!--

@license Apache-2.0

Copyright (c) 2025 The Stdlib Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

-->

# Identity Function

> Evaluate the [identity function][identity-function] of an unsigned 32-bit integer.

<section class="intro">

The [identity-function][identity-function] is defined as

<!-- <equation class="equation" label="eq:identity_function" align="center" raw="f(x) = x" alt="Identity function"> -->

```math
f(x) = x
```

<!-- <div class="equation" align="center" data-raw-text="f(x) = x" data-equation="eq:identity_function">
<img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@ad7afa5d7ec1b1596f8a4828153d8c2e87a90161/lib/node_modules/@stdlib/number/uint32/base/identity/docs/img/equation_identity_function.svg" alt="Identity function">
<br>
</div> -->

<!-- </equation> -->

for all `x`.

</section>

<!-- /.intro -->

<section class="usage">

## Usage

```javascript
var identity = require( '@stdlib/number/uint32/base/identity' );
```

#### identity( x )

Evaluates the [identity function][identity-function] for an unsigned 32-bit integer.

```javascript
var v = identity( 1 );
// returns 1

v = identity( 2 );
// returns 2

v = identity( 0 );
// returns 0

v = identity( 4294967295 );
// returns 4294967295
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var identity = require( '@stdlib/number/uint32/base/identity' );

var opts = {
'dtype': 'uint32'
};

var x = discreteUniform( 100, 0, 50, opts );

var v;
var i;
for ( i = 0; i < x.length; i++ ) {
v = identity( x[ i ] );
console.log( 'identity(%d) = %d', x[ i ], v );
}
```

</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/uint32/base/identity.h"
```

#### stdlib_base_uint32_identity( x )

Evaluates the identity function for an unsigned 32-bit integer.

```c
#include <stdint.h>

uint32_t y = stdlib_base_uint32_identity( 2 );
// returns 2
```

The function accepts the following arguments:

- **x**: `[in] uint32_t` input value.

```c
uint32_t stdlib_base_uint32_identity( const uint32_t 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/uint32/base/identity.h"
#include <stdint.h>
#include <stdio.h>

int main( void ) {
const uint32_t x[] = { 3, 5, 10, 12 };

uint32_t y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_uint32_identity( x[ i ] );
printf( "f(%u) = %u\n", x[ i ], y );
}
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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

<section class="related">

</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="links">

[identity-function]: https://en.wikipedia.org/wiki/Identity_function

<!-- <related-links> -->

<!-- </related-links> -->

</section>

<!-- /.links -->
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/**
* @license Apache-2.0
*
* Copyright (c) 2025 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var bench = require( '@stdlib/bench' );
var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var isnan = require( '@stdlib/math/base/assert/is-nan' );
var pkg = require( './../package.json' ).name;
var identity = require( './../lib' );


// MAIN //

bench( pkg, function benchmark( b ) {
var x;
var y;
var i;

x = discreteUniform( 100, 0, 50, {
'dtype': 'uint32'
});

b.tic();
for ( i = 0; i < b.iterations; i++ ) {
y = identity( x[ i%x.length ] );
if ( isnan( y ) ) {
b.fail( 'should not return NaN' );
}
}
b.toc();
if ( isnan( y ) ) {
b.fail( 'should not return NaN' );
}
b.pass( 'benchmark finished' );
b.end();
});
Original file line number Diff line number Diff line change
@@ -0,0 +1,63 @@
/**
* @license Apache-2.0
*
* Copyright (c) 2025 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var resolve = require( 'path' ).resolve;
var bench = require( '@stdlib/bench' );
var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
var isnan = require( '@stdlib/math/base/assert/is-nan' );
var tryRequire = require( '@stdlib/utils/try-require' );
var pkg = require( './../package.json' ).name;


// VARIABLES //

var identity = tryRequire( resolve( __dirname, './../lib/native.js' ) );
var opts = {
'skip': ( identity instanceof Error )
};


// MAIN //

bench( pkg+'::native', opts, function benchmark( b ) {
var x;
var y;
var i;

x = discreteUniform( 100, 0, 50, {
'dtype': 'uint32'
});

b.tic();
for ( i = 0; i < b.iterations; i++ ) {
y = identity( x[ i%x.length ] );
if ( isnan( y ) ) {
b.fail( 'should not return NaN' );
}
}
b.toc();
if ( isnan( y ) ) {
b.fail( 'should not return NaN' );
}
b.pass( 'benchmark finished' );
b.end();
});
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