time-to-botec

Benchmark sampling in different programming languages
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normalize.js (2188B)

      1 /**
      2 * @license Apache-2.0
      3 *
      4 * Copyright (c) 2018 The Stdlib Authors.
      5 *
      6 * Licensed under the Apache License, Version 2.0 (the "License");
      7 * you may not use this file except in compliance with the License.
      8 * You may obtain a copy of the License at
      9 *
     10 *    http://www.apache.org/licenses/LICENSE-2.0
     11 *
     12 * Unless required by applicable law or agreed to in writing, software
     13 * distributed under the License is distributed on an "AS IS" BASIS,
     14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15 * See the License for the specific language governing permissions and
     16 * limitations under the License.
     17 */
     18 
     19 'use strict';
     20 
     21 // MODULES //
     22 
     23 var FLOAT64_SMALLEST_NORMAL = require( '@stdlib/constants/float64/smallest-normal' );
     24 var isInfinite = require( '@stdlib/math/base/assert/is-infinite' );
     25 var isnan = require( '@stdlib/math/base/assert/is-nan' );
     26 var abs = require( '@stdlib/math/base/special/abs' );
     27 
     28 
     29 // VARIABLES //
     30 
     31 // (1<<52)
     32 var SCALAR = 4503599627370496;
     33 
     34 
     35 // MAIN //
     36 
     37 /**
     38 * Returns a normal number `y` and exponent `exp` satisfying \\(x = y \cdot 2^\mathrm{exp}\\).
     39 *
     40 * @private
     41 * @param {(Array|TypedArray|Object)} out - output array
     42 * @param {number} x - input value
     43 * @returns {(Array|TypedArray|Object)} output array
     44 *
     45 * @example
     46 * var pow = require( '@stdlib/math/base/special/pow' );
     47 *
     48 * var out = normalize( [ 0.0, 0 ], 3.14e-319 );
     49 * // returns [ 1.4141234400356668e-303, -52 ]
     50 *
     51 * var y = out[ 0 ];
     52 * var exp = out[ 1 ];
     53 *
     54 * var bool = ( y*pow(2.0,exp) === 3.14e-319 );
     55 * // returns true
     56 *
     57 * @example
     58 * var out = normalize( [ 0.0, 0 ], 0.0 );
     59 * // returns [ 0.0, 0 ];
     60 *
     61 * @example
     62 * var out = normalize( [ 0.0, 0 ], Infinity );
     63 * // returns [ Infinity, 0 ]
     64 *
     65 * @example
     66 * var out = normalize( [ 0.0, 0 ], -Infinity );
     67 * // returns [ -Infinity, 0 ]
     68 *
     69 * @example
     70 * var out = normalize( [ 0.0, 0 ], NaN );
     71 * // returns [ NaN, 0 ]
     72 */
     73 function normalize( out, x ) {
     74 	if ( isnan( x ) || isInfinite( x ) ) {
     75 		out[ 0 ] = x;
     76 		out[ 1 ] = 0;
     77 		return out;
     78 	}
     79 	if ( x !== 0.0 && abs( x ) < FLOAT64_SMALLEST_NORMAL ) {
     80 		out[ 0 ] = x * SCALAR;
     81 		out[ 1 ] = -52;
     82 		return out;
     83 	}
     84 	out[ 0 ] = x;
     85 	out[ 1 ] = 0;
     86 	return out;
     87 }
     88 
     89 
     90 // EXPORTS //
     91 
     92 module.exports = normalize;