time-to-botec

Benchmark sampling in different programming languages
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cdf.js (1901B)

      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 isnan = require( '@stdlib/math/base/assert/is-nan' );
     24 var sinpi = require( '@stdlib/math/base/special/sinpi' );
     25 var PI = require( '@stdlib/constants/float64/pi' );
     26 
     27 
     28 // MAIN //
     29 
     30 /**
     31 * Evaluates the cumulative distribution function (CDF) for a raised cosine distribution with location parameter `mu` and scale parameter `s` at a value `x`.
     32 *
     33 * @param {number} x - input value
     34 * @param {number} mu - location parameter
     35 * @param {NonNegativeNumber} s - scale parameter
     36 * @returns {Probability} evaluated CDF
     37 *
     38 * @example
     39 * var y = cdf( 0.5, 0.0, 1.0 );
     40 * // returns ~0.909
     41 *
     42 * @example
     43 * var y = cdf( 1.2, 0.0, 1.0 );
     44 * // returns 1.0
     45 *
     46 * @example
     47 * var y = cdf( -0.9, 0.0, 1.0);
     48 * // returns ~0.0
     49 *
     50 * @example
     51 * var y = cdf( 2.0, 0.0, NaN );
     52 * // returns NaN
     53 *
     54 * @example
     55 * var y = cdf( 2.0, NaN, 1.0 );
     56 * // returns NaN
     57 *
     58 * @example
     59 * var y = cdf( NaN, 0.0, 1.0 );
     60 * // returns NaN
     61 */
     62 function cdf( x, mu, s ) {
     63 	var z;
     64 	if (
     65 		isnan( x ) ||
     66 		isnan( mu ) ||
     67 		isnan( s ) ||
     68 		s < 0.0
     69 	) {
     70 		return NaN;
     71 	}
     72 	if ( s === 0.0 ) {
     73 		return ( x < mu ) ? 0.0 : 1.0;
     74 	}
     75 	if ( x < mu - s ) {
     76 		return 0.0;
     77 	}
     78 	if ( x > mu + s ) {
     79 		return 1.0;
     80 	}
     81 	z = ( x - mu ) / s;
     82 	return ( 1.0 + z + ( sinpi( z ) / PI ) ) / 2.0;
     83 }
     84 
     85 
     86 // EXPORTS //
     87 
     88 module.exports = cdf;