time-to-botec

Benchmark sampling in different programming languages
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bernoulli.js (2110B)

      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 isNonNegativeInteger = require( './../../../../base/assert/is-nonnegative-integer' );
     24 var isnan = require( './../../../../base/assert/is-nan' );
     25 var isOdd = require( './../../../../base/assert/is-odd' );
     26 var NINF = require( '@stdlib/constants/float64/ninf' );
     27 var PINF = require( '@stdlib/constants/float64/pinf' );
     28 var BERNOULLI = require( './bernoulli.json' );
     29 
     30 
     31 // VARIABLES //
     32 
     33 var MAX_BERNOULLI = 258|0; // asm type annotation
     34 
     35 
     36 // MAIN //
     37 
     38 /**
     39 * Computes the nth Bernoulli number.
     40 *
     41 * @param {NonNegativeInteger} n - the Bernoulli number to compute
     42 * @returns {number} Bernoulli number
     43 *
     44 * @example
     45 * var y = bernoulli( 0 );
     46 * // returns 1.0
     47 *
     48 * @example
     49 * var y = bernoulli( 1 );
     50 * // returns 0.0
     51 *
     52 * @example
     53 * var y = bernoulli( 2 );
     54 * // returns ~0.167
     55 *
     56 * @example
     57 * var y = bernoulli( 3 );
     58 * // returns 0.0
     59 *
     60 * @example
     61 * var y = bernoulli( 4 );
     62 * // returns ~-0.033
     63 *
     64 * @example
     65 * var y = bernoulli( 5 );
     66 * // returns 0.0
     67 *
     68 * @example
     69 * var y = bernoulli( 20 );
     70 * // returns ~-529.124
     71 *
     72 * @example
     73 * var y = bernoulli( 260 );
     74 * // returns -Infinity
     75 *
     76 * @example
     77 * var y = bernoulli( 262 );
     78 * // returns Infinity
     79 *
     80 * @example
     81 * var y = bernoulli( NaN );
     82 * // returns NaN
     83 */
     84 function bernoulli( n ) {
     85 	if ( isnan( n ) || !isNonNegativeInteger( n ) ) {
     86 		return NaN;
     87 	}
     88 	if ( isOdd( n ) ) {
     89 		return 0.0;
     90 	}
     91 	if ( n > MAX_BERNOULLI ) {
     92 		return ( (n/2)&1 ) ? PINF : NINF;
     93 	}
     94 	return BERNOULLI[ n/2 ];
     95 }
     96 
     97 
     98 // EXPORTS //
     99 
    100 module.exports = bernoulli;