computational-combinatorics/permutation

import {_bitreversal} from './_bitreversal.js';
import {permutation} from './permutation.js';

/**
 * Returns a newly allocated array containing the bitreversal permutation for
 * input <code>n</code> items. Note that <code>n</code> MUST be a power of
 * <code>2</code>.
 *
 * @param {number} n The size of the permutation, must be a power of
 * <code>2</code>.
 * @returns {Array} The bitreversal permutation of size <code>n</code>.
 */
export function bitreversal(n) {
    const sigma = permutation(n);

    _bitreversal(sigma, n);

    return sigma;
}