All files search.js

100% Statements 94/94
100% Branches 13/13
100% Functions 2/2
100% Lines 94/94

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 953x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 6912x 6912x 6912x 20098x 6910x 6910x 13188x 13188x 13188x 20098x 2x 2x 13186x 13186x 6912x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 1096x 1096x 1096x 26646x 26646x 26646x 26646x 6x 6x 26640x 26646x 1090x 1090x 26646x 1096x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x 3x  
/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
 
'use strict';
 
// MODULES //
 
var cdf = require( '@stdlib/stats/base/dists/negative-binomial/cdf' );
 
 
// VARIABLES //
 
var methods;
 
 
// FUNCTIONS //
 
/**
* Performs a search to the left.
*
* @param {NonNegativeInteger} x - starting guess
* @param {Probability} k - probability
* @param {PositiveNumber} r - number of successes until experiment is stopped
* @param {Probability} p - success probability
* @returns {NonNegativeInteger} `k` quantile of the specified distribution
*/
function searchLeft( x, k, r, p ) {
	var xp;
	while ( true ) {
		if ( x === 0 || cdf( x - 1.0, r, p ) < k ) {
			return x;
		}
		xp = x - 1.0;
 
		// Guard against non-advancing updates (e.g., when `x` is `NaN` or is so large that decrementing does not change its value) in order to avoid an infinite loop:
		if ( !( xp < x ) ) {
			return x;
		}
		x = xp;
	}
}
 
/**
* Performs a search to the right.
*
* @param {NonNegativeInteger} x - starting guess
* @param {Probability} k - probability
* @param {PositiveNumber} r - number of successes until experiment is stopped
* @param {Probability} p - success probability
* @returns {NonNegativeInteger} `k` quantile of the specified distribution
*/
function searchRight( x, k, r, p ) {
	var xn;
	while ( true ) {
		xn = x + 1.0;
 
		// Guard against non-advancing updates (e.g., when `x` is `NaN` or is so large that incrementing does not change its value) in order to avoid an infinite loop:
		if ( !( xn > x ) ) {
			return x;
		}
		x = xn;
		if ( cdf( x, r, p ) >= k ) {
			return x;
		}
	}
}
 
 
// MAIN //
 
methods = {
	'left': searchLeft,
	'right': searchRight
};
 
 
// EXPORTS //
 
module.exports = methods;