From fc09af2c880bf741abe8c9284805a92bd63f8742 Mon Sep 17 00:00:00 2001
From: Jeff Cross <middlefloor@gmail.com>
Date: Wed, 18 Jun 2014 09:46:16 -0700
Subject: [PATCH] feat(benchmark): calculate coefficient of variation

---
 benchmark/web/bp.js      | 7 ++++++-
 benchmark/web/bp.spec.js | 5 +++++
 benchmark/web/tree.html  | 2 ++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/benchmark/web/bp.js b/benchmark/web/bp.js
index e0fe43cf6..68130c4da 100644
--- a/benchmark/web/bp.js
+++ b/benchmark/web/bp.js
@@ -43,7 +43,7 @@ bp.Statistics.calculateConfidenceInterval = function(standardDeviation, sampleSi
   return bp.Statistics.criticalValue * standardError;
 };
 
-bp.Statistics.calculateRelativeMarginOfError = function (marginOfError, mean) {
+bp.Statistics.calculateRelativeMarginOfError = function(marginOfError, mean) {
   /*
    * Converts absolute margin of error to a relative margin of error by
    * converting it to a percentage of the mean.
@@ -51,6 +51,10 @@ bp.Statistics.calculateRelativeMarginOfError = function (marginOfError, mean) {
   return (marginOfError / mean);
 };
 
+bp.Statistics.calculateCoefficientOfVariation = function(standardDeviation, mean) {
+  return standardDeviation / mean;
+};
+
 bp.Statistics.calculateStandardDeviation = function(sample, mean) {
   var deviation = 0;
   sample.forEach(function(x) {
@@ -256,6 +260,7 @@ bp.Report.calcStats = function() {
       avg: avg,
       times: tpa.fmtTimes,
       timesStandardDeviation: timesStandardDeviation,
+      coefficientOfVariation: bp.Statistics.calculateCoefficientOfVariation(timesStandardDeviation, avg.time),
       timesRelativeMarginOfError: bp.Statistics.calculateRelativeMarginOfError(timesConfidenceInterval, avg.time),
       gcTimes: tpa.fmtGcTimes,
       garbageTimes: tpa.fmtGarbageTimes,
diff --git a/benchmark/web/bp.spec.js b/benchmark/web/bp.spec.js
index 92832f9eb..455c820fa 100644
--- a/benchmark/web/bp.spec.js
+++ b/benchmark/web/bp.spec.js
@@ -57,6 +57,11 @@ describe('bp', function() {
           674.64,701.78,668.33,662.15,663.34,677.32,664.25,1233.00,1100.80,716.15,681.52,671.23,702.70,686.89,939.39,830.28,695.46,695.66,675.15,667.48], 750.38)).toBe(158.57877026559186);
       });
     });
+
+
+    describe('.calculateCoefficientOfVariation()', function() {
+      expect(bp.Statistics.calculateCoefficientOfVariation(0.5, 5)).toBe(0.1);
+    });
   });
 
 
diff --git a/benchmark/web/tree.html b/benchmark/web/tree.html
index d07f4c7ef..cb8d6bcb7 100644
--- a/benchmark/web/tree.html
+++ b/benchmark/web/tree.html
@@ -72,6 +72,8 @@
                 <br>
                 deviation: <%= timesStandardDeviation %>
                 <br>
+                coefficient of variation: <%= Math.round(coefficientOfVariation * 100) %>%
+                <br>
                 gc:<%= avg.gcTime %>ms
                 <br>
                 combined: <%= avg.combinedTime %>ms