time-to-botec

Benchmark sampling in different programming languages
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quantile.js (2014B)

      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 isInteger = require( '@stdlib/math/base/assert/is-integer' );
     24 var isnan = require( '@stdlib/math/base/assert/is-nan' );
     25 var floor = require( '@stdlib/math/base/special/floor' );
     26 
     27 
     28 // MAIN //
     29 
     30 /**
     31 * Evaluates the quantile function for a discrete uniform distribution with minimum support `a` and maximum support `b` at a probability `p`.
     32 *
     33 * @param {Probability} p - input value
     34 * @param {integer} a - minimum support
     35 * @param {integer} b - maximum support
     36 * @returns {integer} evaluated quantile function
     37 *
     38 * @example
     39 * var y = quantile( 0.8, 0, 1 );
     40 * // returns 1
     41 *
     42 * @example
     43 * var y = quantile( 0.5, 0, 10 );
     44 * // returns 5
     45 *
     46 * @example
     47 * var y = quantile( 1.1, 0, 1 );
     48 * // returns NaN
     49 *
     50 * @example
     51 * var y = quantile( -0.2, 0, 1 );
     52 * // returns NaN
     53 *
     54 * @example
     55 * var y = quantile( 0.5, 1, 1.5 );
     56 * // returns NaN
     57 *
     58 * @example
     59 * var y = quantile( NaN, 0, 1 );
     60 * // returns NaN
     61 *
     62 * @example
     63 * var y = quantile( 0.0, NaN, 1.0 );
     64 * // returns NaN
     65 *
     66 * @example
     67 * var y = quantile( 0.0, 0, NaN );
     68 * // returns NaN
     69 *
     70 * @example
     71 * var y = quantile( 0.5, 2, 1 );
     72 * // returns NaN
     73 */
     74 function quantile( p, a, b ) {
     75 	var n;
     76 	if (
     77 		isnan( p ) ||
     78 		isnan( a ) ||
     79 		isnan( b ) ||
     80 		!isInteger( a ) ||
     81 		!isInteger( b ) ||
     82 		a > b ||
     83 		p < 0.0 ||
     84 		p > 1.0
     85 	) {
     86 		return NaN;
     87 	}
     88 	n = b - a + 1;
     89 	return a + floor( p * n );
     90 }
     91 
     92 
     93 // EXPORTS //
     94 
     95 module.exports = quantile;