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 | 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 13x 13x 13x 13x 13x 13x 13x 13x 13x 13x 61x 61x 61x 61x 61x 61x 61x 61x 13x 13x 2x 2x 2x 2x 2x | /**
* @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 floor = require( '@stdlib/math/base/special/floor' );
// FUNCTIONS //
var slice = Array.prototype.slice;
// MAIN //
/**
* Samples uniformly without replacement using the Fisher-Yates shuffle.
*
* ## References
*
* - Knuth, Donald E. 1997. _The Art of Computer Programming, Volume 2 (3rd Ed.): Seminumerical Algorithms_. Boston, MA, USA: Addison-Wesley Longman Publishing Co., Inc.
*
* @private
* @param {ArrayLike} x - array-like object from which to sample
* @param {NonNegativeInteger} size - sample size
* @param {Function} rand - PRNG for generating uniformly distributed numbers
* @returns {Array} sample
*/
function fisherYates( x, size, rand ) {
var tmp;
var N;
var i;
var j;
N = x.length;
// Note: we skip the first element, as no further swaps are possible given that all other indices are excluded from swapping...
for ( i = N-1; i > 0; i-- ) {
// Generate an integer index on the interval: [0,i]
j = floor( rand()*(i+1) );
// Swap elements:
tmp = x[ i ];
x[ i ] = x[ j ];
x[ j ] = tmp;
}
return slice.call( x, 0, size );
}
// EXPORTS //
module.exports = fisherYates;
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