time-to-botec

Benchmark sampling in different programming languages
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README.md (2463B)

      1 <!--
      2 
      3 @license Apache-2.0
      4 
      5 Copyright (c) 2018 The Stdlib Authors.
      6 
      7 Licensed under the Apache License, Version 2.0 (the "License");
      8 you may not use this file except in compliance with the License.
      9 You may obtain a copy of the License at
     10 
     11    http://www.apache.org/licenses/LICENSE-2.0
     12 
     13 Unless required by applicable law or agreed to in writing, software
     14 distributed under the License is distributed on an "AS IS" BASIS,
     15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     16 See the License for the specific language governing permissions and
     17 limitations under the License.
     18 
     19 -->
     20 
     21 # Flipsign
     22 
     23 > Return a [double-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `x*y`.
     24 
     25 <section class="usage">
     26 
     27 ## Usage
     28 
     29 ```javascript
     30 var flipsign = require( '@stdlib/math/base/special/flipsign' );
     31 ```
     32 
     33 #### flipsign( x, y )
     34 
     35 Returns a [double-precision floating-point number][ieee754] with the magnitude of `x` and the sign of `x*y`; i.e., only return `-x` when `y` is a negative number.
     36 
     37 ```javascript
     38 var z = flipsign( -3.14, 10.0 );
     39 // returns -3.14
     40 
     41 z = flipsign( -3.14, -1.0 );
     42 // returns 3.14
     43 
     44 z = flipsign( 1.0, -0.0 );
     45 // returns -1.0
     46 
     47 z = flipsign( -3.14, -0.0 );
     48 // returns 3.14
     49 
     50 z = flipsign( -0.0, 1.0 );
     51 // returns -0.0
     52 
     53 z = flipsign( 0.0, -1.0 );
     54 // returns -0.0
     55 ```
     56 
     57 </section>
     58 
     59 <!-- /.usage -->
     60 
     61 <section class="notes">
     62 
     63 ## Notes
     64 
     65 -   According to the [IEEE 754][ieee754] standard, a `NaN` has a biased exponent equal to `2047`, a significand greater than `0`, and a sign bit equal to **either** `1` **or** `0`. In which case, `NaN` may not correspond to just one but many binary representations. Accordingly, care should be taken to ensure that `y` is **not** `NaN`, else behavior may be indeterminate.
     66 
     67 </section>
     68 
     69 <!-- /.notes -->
     70 
     71 <section class="examples">
     72 
     73 ## Examples
     74 
     75 <!-- eslint no-undef: "error" -->
     76 
     77 ```javascript
     78 var randu = require( '@stdlib/random/base/randu' );
     79 var flipsign = require( '@stdlib/math/base/special/flipsign' );
     80 
     81 var x;
     82 var y;
     83 var z;
     84 var i;
     85 
     86 // Generate random double-precision floating-point numbers `x` and `y` and flip the sign of `x` only if `y` is negative...
     87 for ( i = 0; i < 100; i++ ) {
     88     x = (randu()*100.0) - 50.0;
     89     y = (randu()*10.0) - 5.0;
     90     z = flipsign( x, y );
     91     console.log( 'x: %d, y: %d => %d', x, y, z );
     92 }
     93 ```
     94 
     95 </section>
     96 
     97 <!-- /.examples -->
     98 
     99 <section class="links">
    100 
    101 [ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
    102 
    103 </section>
    104 
    105 <!-- /.links -->