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feat: add math/base/special/ldexpf
PR-URL: #2805 Ref: #649 --------- Signed-off-by: Gunj Joshi <[email protected]> Signed-off-by: Philipp Burckhardt <[email protected]> Co-authored-by: Philipp Burckhardt <[email protected]> Reviewed-by: Philipp Burckhardt <[email protected]>
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‎lib/node_modules/@stdlib/math/base/special/ldexpf/README.md

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<!--
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@license Apache-2.0
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Copyright (c) 2024 The Stdlib Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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# ldexpf
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> Multiply a [single-precision floating-point number][ieee754] by an integer power of two.
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<section class="usage">
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## Usage
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```javascript
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var ldexpf = require( '@stdlib/math/base/special/ldexpf' );
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```
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#### ldexpf( frac, exp )
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Multiplies a [single-precision floating-point number][ieee754] by an `integer` power of two (i.e., `x = frac * 2^exp`).
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```javascript
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var x = ldexpf( 0.5, 3 ); // => 0.5 * 2^3 = 0.5 * 8
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// returns 4.0
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x = ldexpf( 4.0, -2 ); // => 4 * 2^(-2) = 4 * (1/4)
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// returns 1.0
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```
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If `frac` equals positive or negative zero, `NaN`, or positive or negative `infinity`, the function returns a value equal to `frac`.
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```javascript
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var x = ldexpf( 0.0, 20 );
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// returns 0.0
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x = ldexpf( -0.0, 39 );
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// returns -0.0
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x = ldexpf( NaN, -101 );
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// returns NaN
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x = ldexpf( Infinity, 11 );
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// returns Infinity
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x = ldexpf( -Infinity, -118 );
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// returns -Infinity
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```
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<section class="usage">
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<section class="notes">
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## Notes
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// TODO: update this once we have `frexpf`.
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- This function is the inverse of [`frexp`][@stdlib/math/base/special/frexp].
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</section>
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<!-- /.notes -->
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<section class="examples">
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## Examples
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<!-- eslint no-undef: "error" -->
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```javascript
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var linspace = require( '@stdlib/array/base/linspace' );
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var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
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var ldexpf = require( '@stdlib/math/base/special/ldexpf' );
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var frac = linspace( 0.0, 100.0, 10 );
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var exp = discreteUniform( 100, 0, 10 );
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var i;
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for ( i = 0; i < frac.length; i++ ) {
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console.log( 'ldexpf(%d,%d) = %d', frac[ i ], exp[ i ], ldexpf( frac[ i ], exp[ i ] ) );
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}
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```
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</section>
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<!-- /.examples -->
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<!-- C interface documentation. -->
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* * *
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<section class="c">
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## C APIs
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<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
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<section class="intro">
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</section>
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<!-- /.intro -->
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<!-- C usage documentation. -->
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<section class="usage">
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### Usage
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```c
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#include "stdlib/math/base/special/ldexpf.h"
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```
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#### stdlib_base_ldexpf( frac, exp )
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Multiplies a [single-precision floating-point number][ieee754] by an integer power of two (i.e., `x = frac * 2^exp`).
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```c
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float x = stdlib_base_ldexpf( 0.5f, 3 ); // => 0.5 * 2^3 = 0.5 * 8
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// returns 4.0f
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```
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The function accepts the following arguments:
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- **frac**: `[in] float` input value.
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- **exp**: `[in] int32_t` integer power of two.
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```c
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float stdlib_base_ldexpf( const float frac, const int32_t exp );
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```
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</section>
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<!-- /.usage -->
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<!-- C API usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="notes">
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</section>
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<!-- /.notes -->
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<!-- C API usage examples. -->
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<section class="examples">
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### Examples
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```c
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#include "stdlib/math/base/special/ldexpf.h"
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#include <stdint.h>
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#include <stdio.h>
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int main( void ) {
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float y;
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int i;
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const float frac[] = { 0.5f, 5.0f, 0.0f, 3.5f, 7.9f };
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const int32_t exp[] = { 3, -2, 20, 39, 14 };
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for ( i = 0; i < 5; i++ ) {
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y = stdlib_base_ldexpf( frac[ i ], exp[ i ] );
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printf( "ldexpf(%f, %d) = %f\n", frac[ i ], exp[ i ], y );
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}
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}
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```
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</section>
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<!-- /.examples -->
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</section>
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<!-- /.c -->
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<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
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<section class="related">
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</section>
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<!-- /.related -->
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<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="links">
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[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
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[@stdlib/math/base/special/frexp]: https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/math/base/special/frexp
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<!-- <related-links> -->
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<!-- </related-links> -->
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</section>
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<!-- /.links -->

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

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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2024 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var bench = require( '@stdlib/bench' );
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var randu = require( '@stdlib/random/array/uniform' );
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var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
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var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
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var pkg = require( './../package.json' ).name;
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var ldexpf = require( './../lib' );
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// MAIN //
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bench( pkg, function benchmark( b ) {
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var x;
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var y;
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var z;
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var i;
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x = randu( 100, -10.0, 10.0 );
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y = discreteUniform( 100, -1020.0, 1020.0 );
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b.tic();
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for ( i = 0; i < b.iterations; i++ ) {
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z = ldexpf( x[ i % x.length ], y[ i % y.length ] );
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if ( isnanf( z ) ) {
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b.fail( 'should not return NaN' );
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}
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}
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b.toc();
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if ( isnanf( z ) ) {
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b.fail( 'should not return NaN' );
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}
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b.pass( 'benchmark finished' );
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b.end();
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});

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

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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2024 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var resolve = require( 'path' ).resolve;
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var bench = require( '@stdlib/bench' );
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var randu = require( '@stdlib/random/base/randu' );
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var discreteUniform = require( '@stdlib/random/array/discrete-uniform' );
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var isnanf = require( '@stdlib/math/base/assert/is-nanf' );
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var tryRequire = require( '@stdlib/utils/try-require' );
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var pkg = require( './../package.json' ).name;
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// VARIABLES //
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var ldexpf = tryRequire( resolve( __dirname, './../lib/native.js' ) );
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var opts = {
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'skip': ( ldexpf instanceof Error )
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};
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// MAIN //
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bench( pkg+'::native', opts, function benchmark( b ) {
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var x;
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var y;
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var z;
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var i;
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x = randu( 100, -10.0, 10.0 );
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y = discreteUniform( 100, -1020.0, 1020.0 );
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b.tic();
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for ( i = 0; i < b.iterations; i++ ) {
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z = ldexpf( x[ i % x.length ], y[ i % y.length ] );
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if ( isnanf( z ) ) {
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b.fail( 'should not return NaN' );
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}
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}
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b.toc();
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if ( isnanf( z ) ) {
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b.fail( 'should not return NaN' );
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}
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b.pass( 'benchmark finished' );
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b.end();
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});

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