tweak: add coefficient of variation

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "cSpell.words": ["Stdev"]
+}

lib/findPaths.js

@@ -5,6 +5,7 @@ import {
   formatLargeOrSmall,
   avg,
   hackyGeomMean,
+  getCoefficientOfVariation,
 } from "../lib/utils.js";
 
 /* Functions */
@@ -301,6 +302,7 @@ export function CreateTable({ tableRows }) {
             <th>Possible relative values</th>
             <th> &nbsp;&nbsp;&nbsp;</th>
             <th>geomMean(relative values)</th>
+            <th>Coefficient of variation</th>
           </tr>
         </thead>
         <tbody>
@@ -317,6 +319,9 @@ export function CreateTable({ tableRows }) {
               <td className="">
                 {formatLargeOrSmall(hackyGeomMean(row.distances))}
               </td>
+              <td className="">
+                {formatLargeOrSmall(getCoefficientOfVariation(row.distances))}
+              </td>
             </tr>
           ))}
         </tbody>

lib/utils.js

@@ -117,3 +117,26 @@ export function conservativeNumMergeSortSteps(n) {
 // export const geomMean = (arr) => arr.reduce((a, b) => a * b, 1); // ^ (1 / arr.length); // didn't work so well for low numbers.
 
 export const increasingList = (n) => Array.from(Array(n).keys());
+
+function getStdev(arr) {
+  if (Array.isArray(arr) && arr.length > 0) {
+    const n = arr.length;
+    const mean = arr.reduce((a, b) => a + b) / n;
+    return Math.sqrt(
+      arr.map((x) => Math.pow(x - mean, 2)).reduce((a, b) => a + b) / n
+    );
+  } else {
+    return 0;
+  }
+}
+
+export const getCoefficientOfVariation = (arr) => {
+  let nonPositiveNumbers = arr.filter((x) => x <= 0);
+  if (nonPositiveNumbers.length == 0) {
+    let gm = geomMean(arr);
+    let stdev = getStdev(arr);
+    return stdev / gm;
+  } else {
+    return getStdev(arr) / avg(arr);
+  }
+};