feat: add math/base/special/roundnf implementation

lib/node_modules/@stdlib/math/base/special/roundnf/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.
+
+-->
+
+# roundn
+
+> Round a double-precision floating-point number to the nearest multiple of 10^n.
+
+<section class="usage">
+
+## Usage
+
+```javascript
+var roundn = require( '@stdlib/math/base/special/roundn' );
+```
+
+#### roundn( x, n )
+
+Rounds a double-precision floating-point number to the nearest multiple of `10^n`.
+
+```javascript
+// Round a value to 2 decimal places:
+var v = roundn( 3.141592653589793, -2 );
+// returns 3.14
+
+// If n = 0, `roundn` behaves like `round`:
+v = roundn( 3.141592653589793, 0 );
+// returns 3.0
+
+// Round a value to the nearest thousand:
+v = roundn( 12368.0, 3 );
+// returns 12000.0
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+## Notes
+
+-   When operating on [floating-point numbers][ieee754] in bases other than `2`, rounding to specified digits can be **inexact**. For example,
+
+    ```javascript
+    var x = 0.2 + 0.1;
+    // returns 0.30000000000000004
+
+    // Should round to 0.3...
+    var v = roundn( x, -16 );
+    // returns 0.3000000000000001
+    ```
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+## Examples
+
+<!-- eslint no-undef: "error" -->
+
+```javascript
+var randu = require( '@stdlib/random/base/randu' );
+var roundn = require( '@stdlib/math/base/special/roundn' );
+
+var x;
+var n;
+var v;
+var i;
+
+for ( i = 0; i < 100; i++ ) {
+    x = (randu()*100.0) - 50.0;
+    n = roundn( randu()*5.0, 0 );
+    v = roundn( x, -n );
+    console.log( 'x: %d. Number of decimals: %d. Rounded: %d.', x, n, 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/math/base/special/roundn.h"
+```
+
+#### stdlib_base_roundn( x, n )
+
+Rounds a double-precision floating-point number to the nearest multiple of `10^n`.
+
+```c
+double y = stdlib_base_roundn( 3.14, -2 );
+// returns 3.14
+```
+
+The function accepts the following arguments:
+
+-   **x**: `[in] double` input value.
+-   **n**: `[in] int32_t` integer power of 10.
+
+```c
+double stdlib_base_roundn( const double x, const int32_t n );
+```
+
+</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/math/base/special/roundn.h"
+#include <stdio.h>
+
+int main( void ) {
+    const double x[] = { 3.14, -3.14, 0.0, 0.0/0.0 };
+
+    double y;
+    int i;
+    for ( i = 0; i < 4; i++ ) {
+        y = stdlib_base_roundn( x[ i ], -2 );
+        printf( "roundn(%lf) = %lf\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">
+
+* * *
+
+## See Also
+
+-   <span class="package-name">[`@stdlib/math/base/special/ceiln`][@stdlib/math/base/special/ceiln]</span><span class="delimiter">: </span><span class="description">round a numeric value to the nearest multiple of 10^n toward positive infinity.</span>
+-   <span class="package-name">[`@stdlib/math/base/special/floorn`][@stdlib/math/base/special/floorn]</span><span class="delimiter">: </span><span class="description">round a double-precision floating-point number to the nearest multiple of 10^n toward negative infinity.</span>
+-   <span class="package-name">[`@stdlib/math/base/special/round`][@stdlib/math/base/special/round]</span><span class="delimiter">: </span><span class="description">round a numeric value to the nearest integer.</span>
+-   <span class="package-name">[`@stdlib/math/base/special/roundb`][@stdlib/math/base/special/roundb]</span><span class="delimiter">: </span><span class="description">round a numeric value to the nearest multiple of b^n on a linear scale.</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="links">
+
+[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
+
+<!-- <related-links> -->
+
+[@stdlib/math/base/special/ceiln]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/ceiln
+
+[@stdlib/math/base/special/floorn]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/floorn
+
+[@stdlib/math/base/special/round]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/round
+
+[@stdlib/math/base/special/roundb]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/roundb
+
+<!-- </related-links> -->
+
+</section>
+
+<!-- /.links -->

lib/node_modules/@stdlib/math/base/special/roundnf/benchmark/benchmark.js

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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 uniform = require( '@stdlib/random/base/uniform' );
+var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
+var pkg = require( './../package.json' ).name;
+var roundn = require( './../lib' );
+
+
+// MAIN //
+
+bench( pkg, function benchmark( b ) {
+	var x;
+	var y;
+	var i;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		x = uniform( -5.0e6, 5.0e6 );
+		y = roundn( x, -2 );
+		if ( isnanf( y ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnanf( y ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});

lib/node_modules/@stdlib/math/base/special/roundnf/benchmark/benchmark.native.js

@@ -0,0 +1,61 @@
+/**
+* @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 uniform = require( '@stdlib/random/base/uniform' );
+var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var float64ToFloat32 = require('@stdlib/number/float64/base/to-float32');
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var roundnf = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( roundn instanceof Error )
+};
+
+
+// MAIN //
+
+bench( pkg+'::native', opts, function benchmark( b ) {
+	var x;
+	var y;
+	var i;
+
+	b.tic();
+	for ( i = 0; i < b.iterations; i++ ) {
+		x = uniform( -500.0, 500.0 );
+		y = roundnf( float64ToFloat32(x), -2 );
+		if ( isnanf( y ) ) {
+			b.fail( 'should not return NaN' );
+		}
+	}
+	b.toc();
+	if ( isnanf( y ) ) {
+		b.fail( 'should not return NaN' );
+	}
+	b.pass( 'benchmark finished' );
+	b.end();
+});