85 lines
2.2 KiB
TypeScript
85 lines
2.2 KiB
TypeScript
/*
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This file is part of GNU Taler
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(C) 2022 Taler Systems S.A.
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GNU Taler is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3, or (at your option) any later version.
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GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
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@author: Boss Marco
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*/
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const getRandomInt = function (max: number) {
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return Math.floor(Math.random() * max);
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};
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abstract class BenchMerchantIDGenerator {
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abstract getRandomMerchantID(): number;
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}
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class ZipfGenerator extends BenchMerchantIDGenerator {
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weights: number[];
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total_weight: number;
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constructor(numMerchants: number) {
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super();
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this.weights = new Array<number>(numMerchants);
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for (var i = 0; i < this.weights.length; i++) {
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/* we use integers (floor), make sure we have big enough values
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* by multiplying with
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* numMerchants again */
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this.weights[i] = Math.floor((numMerchants / (i + 1)) * numMerchants);
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}
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this.total_weight = this.weights.reduce((p, n) => p + n);
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}
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getRandomMerchantID(): number {
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let random = getRandomInt(this.total_weight);
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let current = 0;
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for (var i = 0; i < this.weights.length; i++) {
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current += this.weights[i];
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if (random <= current) {
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return i + 1;
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}
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}
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/* should never come here */
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return getRandomInt(this.weights.length);
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}
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}
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class RandomGenerator extends BenchMerchantIDGenerator {
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max: number;
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constructor(numMerchants: number) {
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super();
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this.max = numMerchants;
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}
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getRandomMerchantID() {
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return getRandomInt(this.max);
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}
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}
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export default function (
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type: string,
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maxID: number,
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): BenchMerchantIDGenerator {
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switch (type) {
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case "zipf":
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return new ZipfGenerator(maxID);
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case "rand":
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return new RandomGenerator(maxID);
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default:
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throw new Error("Valid types are 'zipf' and 'rand'");
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}
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}
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