Display geometric mean of benchmarks in compare site

Author: Kobzol

site/static/compare.html

@@ -419,6 +419,10 @@ <h2>Comparing <span id="stat-header">{{stat}}</span> between <span id="before">{
                         </span>
                     </div>
                 </div>
+                <div class="section">
+                    <span style="font-weight: bold; width: 30%; margin-left: 15%;">Geometric mean</span>
+                    <span v-bind:class="percentClass(geoMean)">{{ geoMean.toFixed(2) }}%</span>
+                </div>
             </div>
             <table id="benches" class="compare">
                 <tbody>
@@ -703,6 +707,21 @@ <h2>Comparing <span id="stat-header">{{stat}}</span> between <span id="before">{
                 stat() {
                     return findQueryParam("stat") || "instructions:u";
                 },
+                geoMean() {
+                    if (this.data === null) {
+                        return "N/A";
+                    }
+
+                    let geomean = 1;
+                    for (let d of this.data.comparisons) {
+                        const datumA = d.statistics[0];
+                        const datumB = d.statistics[1];
+                        const percent = 100 * ((datumB - datumA) / datumA);
+                        geomean *= percent + 100;
+                    }
+                    geomean = Math.pow(geomean, 1.0 / this.data.comparisons.length);
+                    return geomean - 100;
+                },
                 summary() {
                     // Create object with each test case that is not filtered out as a key
                     const filtered = Object.fromEntries(this.benches.flatMap(b => b.testCases.map(v => [b.name + "-" + v.scenario, true])));