From d993703e9b52651d456e7eceb691f90228b2cd5e Mon Sep 17 00:00:00 2001
From: Andrew Steinborn <andrew@steinborn.me>
Date: Tue, 26 May 2020 05:49:58 -0400
Subject: Add 95th percentile MSPT and replace average MSPT with median MSPT
 (#55)

---
 .../me/lucko/spark/common/util/RollingAverage.java | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'spark-common/src/main/java/me/lucko/spark/common/util')

diff --git a/spark-common/src/main/java/me/lucko/spark/common/util/RollingAverage.java b/spark-common/src/main/java/me/lucko/spark/common/util/RollingAverage.java
index 5cf5bb5..1e5e8b2 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/util/RollingAverage.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/util/RollingAverage.java
@@ -23,6 +23,8 @@ package me.lucko.spark.common.util;
 import java.math.BigDecimal;
 import java.math.RoundingMode;
 import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Queue;
 
 public class RollingAverage {
@@ -79,4 +81,26 @@ public class RollingAverage {
         }
     }
 
+    public double getMedian() {
+        return getPercentile(50);
+    }
+
+    public double getPercentile(int percentile) {
+        if (percentile < 0 || percentile > 100) {
+            throw new IllegalArgumentException("Invalid percentage " + percentile);
+        }
+
+        List<BigDecimal> sortedSamples;
+        synchronized (this) {
+            if (this.samples.isEmpty()) {
+                return 0;
+            }
+            sortedSamples = new ArrayList<>(this.samples);
+        }
+        sortedSamples.sort(null);
+
+        int rank = (int) Math.ceil((percentile / 100d) * sortedSamples.size());
+        return sortedSamples.get(rank).doubleValue();
+    }
+
 }
-- 
cgit