split utils

utils/probabilityUtils.js

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+"use strict";
+// FMG utils related to randomness
+
+// random number in a range
+function rand(min, max) {
+  if (min === undefined && max === undefined) return Math.random();
+  if (max === undefined) {
+    max = min;
+    min = 0;
+  }
+  return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+// probability shorthand
+function P(probability) {
+  if (probability >= 1) return true;
+  if (probability <= 0) return false;
+  return Math.random() < probability;
+}
+
+function each(n) {
+  return i => i % n === 0;
+}
+
+// random number (normal or gaussian distribution)
+function gauss(expected = 100, deviation = 30, min = 0, max = 300, round = 0) {
+  return rn(minmax(d3.randomNormal(expected, deviation)(), min, max), round);
+}
+
+// probability shorthand for floats
+function Pint(float) {
+  return ~~float + +P(float % 1);
+}
+
+// return random value from the array
+function ra(array) {
+  return array[Math.floor(Math.random() * array.length)];
+}
+
+// return random value from weighted array {"key1":weight1, "key2":weight2}
+function rw(object) {
+  const array = [];
+  for (const key in object) {
+    for (let i = 0; i < object[key]; i++) {
+      array.push(key);
+    }
+  }
+  return array[Math.floor(Math.random() * array.length)];
+}
+
+// return a random integer from min to max biased towards one end based on exponent distribution (the bigger ex the higher bias towards min)
+function biased(min, max, ex) {
+  return Math.round(min + (max - min) * Math.pow(Math.random(), ex));
+}
+
+// get number from string in format "1-3" or "2" or "0.5"
+function getNumberInRange(r) {
+  if (typeof r !== "string") {
+    ERROR && console.error("The value should be a string", r);
+    return 0;
+  }
+  if (!isNaN(+r)) return ~~r + +P(r - ~~r);
+  const sign = r[0] === "-" ? -1 : 1;
+  if (isNaN(+r[0])) r = r.slice(1);
+  const range = r.includes("-") ? r.split("-") : null;
+  if (!range) {
+    ERROR && console.error("Cannot parse the number. Check the format", r);
+    return 0;
+  }
+  const count = rand(range[0] * sign, +range[1]);
+  if (isNaN(count) || count < 0) {
+    ERROR && console.error("Cannot parse number. Check the format", r);
+    return 0;
+  }
+  return count;
+}