From 935a119621a9ff7a79c410d6cc1bf0c9daa89216 Mon Sep 17 00:00:00 2001
From: Marco Boss <bossm8@bfh.ch>
Date: Mon, 9 May 2022 14:28:12 +0200
Subject: add bench3 for zipf and random merchant selection (by id)

---
 .../src/benchMerchantIDGenerator.ts                | 83 ++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 packages/taler-wallet-cli/src/benchMerchantIDGenerator.ts

(limited to 'packages/taler-wallet-cli/src/benchMerchantIDGenerator.ts')

diff --git a/packages/taler-wallet-cli/src/benchMerchantIDGenerator.ts b/packages/taler-wallet-cli/src/benchMerchantIDGenerator.ts
new file mode 100644
index 000000000..b83c12bb8
--- /dev/null
+++ b/packages/taler-wallet-cli/src/benchMerchantIDGenerator.ts
@@ -0,0 +1,83 @@
+/*
+ This file is part of GNU Taler
+ (C) 2022 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ 
+ @author: Boss Marco
+ */
+
+const getRandomInt = function(max: number) {
+  return Math.floor(Math.random() * max);
+}
+
+abstract class BenchMerchantIDGenerator {
+  abstract getRandomMerchantID(): number
+}
+
+class ZipfGenerator extends BenchMerchantIDGenerator {
+
+  weights: number[];
+  total_weight: number;
+
+  constructor(numMerchants: number) {
+    super();
+    this.weights = new Array<number>(numMerchants);
+    for (var i = 0; i < this.weights.length; i++) {
+      /* we use integers (floor), make sure we have big enough values 
+       * by multiplying with
+       * numMerchants again */
+      this.weights[i] = Math.floor((numMerchants/(i+1)) * numMerchants);
+    }
+    this.total_weight = this.weights.reduce((p, n) => p + n);
+  }
+
+  getRandomMerchantID(): number {
+    let random = getRandomInt(this.total_weight);
+    let current = 0;
+
+    for (var i = 0; i < this.weights.length; i++) {
+      current += this.weights[i];
+      if (random <= current) {
+          return i+1;
+      }
+    }
+
+    /* should never come here */
+    return getRandomInt(this.weights.length);
+  }
+}
+
+class RandomGenerator extends BenchMerchantIDGenerator {
+
+  max: number
+
+  constructor(numMerchants: number) {
+    super();
+    this.max = numMerchants
+  }
+
+  getRandomMerchantID() {
+    return getRandomInt(this.max);
+  }
+}
+
+export default function(type: string, maxID: number): BenchMerchantIDGenerator {
+  switch (type) {
+    case "zipf":
+      return new ZipfGenerator(maxID);
+    case "rand":
+      return new RandomGenerator(maxID);
+    default:
+      throw new Error("Valid types are 'zipf' and 'rand'");
+  }
+}
-- 
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