time-to-botec

Benchmark sampling in different programming languages
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README.md (3079B)

      1 <!--
      2 
      3 @license Apache-2.0
      4 
      5 Copyright (c) 2021 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 # fromInt64Bytes
     22 
     23 > Convert a signed 64-bit integer byte array to a [double-precision floating-point number][ieee754].
     24 
     25 <section class="usage">
     26 
     27 ## Usage
     28 
     29 ```javascript
     30 var fromInt64Bytes = require( '@stdlib/number/float64/base/from-int64-bytes' );
     31 ```
     32 
     33 #### fromInt64Bytes( bytes, stride, offset )
     34 
     35 Converts a signed 64-bit integer byte array to a [double-precision floating-point number][ieee754].
     36 
     37 ```javascript
     38 var Uint8Array = require( '@stdlib/array/uint8' );
     39 
     40 var bytes = new Uint8Array( [ 255, 255, 255, 255, 255, 255, 255, 255 ] );
     41 var out = fromInt64Bytes( bytes, 1, 0 );
     42 // returns -1.0
     43 ```
     44 
     45 The function supports providing a `stride` and an index `offset` for indexing into a provided byte array.
     46 
     47 <!-- eslint-disable max-len -->
     48 
     49 ```javascript
     50 var Uint8Array = require( '@stdlib/array/uint8' );
     51 
     52 var bytes = new Uint8Array( [ 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255 ] );
     53 var out = fromInt64Bytes( bytes, 2, 1 );
     54 // returns -1.0
     55 ```
     56 
     57 </section>
     58 
     59 <!-- /.usage -->
     60 
     61 <section class="notes">
     62 
     63 ## Notes
     64 
     65 -   The function assumes host byte order (endianness).
     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 IS_LITTLE_ENDIAN = require( '@stdlib/assert/is-little-endian' );
     79 var discreteUniform = require( '@stdlib/random/base/discrete-uniform' );
     80 var bernoulli = require( '@stdlib/random/base/bernoulli' );
     81 var Uint8Array = require( '@stdlib/array/uint8' );
     82 var fromInt64Bytes = require( '@stdlib/number/float64/base/from-int64-bytes' );
     83 
     84 var bytes;
     85 var sgn;
     86 var x;
     87 var b;
     88 var s;
     89 var i;
     90 var j;
     91 var k;
     92 
     93 bytes = new Uint8Array( 8 );
     94 if ( IS_LITTLE_ENDIAN ) {
     95     k = 0;
     96     s = 1;
     97 } else {
     98     k = 7;
     99     s = -1;
    100 }
    101 // Generate random integer-valued doubles on the interval (-2^16, 2^16)...
    102 for ( i = 0; i < 10; i++ ) {
    103     // Determine the sign:
    104     sgn = ( bernoulli( 0.5 ) ) ? 0 : 128; // 2^7
    105 
    106     // Set a subset of individual (lower-order) bytes:
    107     for ( j = 0; j < 2; j++ ) {
    108         b = discreteUniform( 0, 255 ); // 2^8-1
    109         bytes[ k+(j*s) ] = b;
    110     }
    111     // Set higher-order bytes using two's complement:
    112     for ( j = 2; j < 8; j++ ) {
    113         bytes[ k+(j*s) ] = ( sgn ) ? 255 : 0; // 2^8-1
    114     }
    115     // Convert the bytes to a double:
    116     x = fromInt64Bytes( bytes, 1, 0 );
    117     console.log( bytes + ' => ' + x );
    118 }
    119 ```
    120 
    121 </section>
    122 
    123 <!-- /.examples -->
    124 
    125 <section class="links">
    126 
    127 [ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
    128 
    129 </section>
    130 
    131 <!-- /.links -->