From 0e0614b5add70db580cd4852b88dac22a2b70dfc Mon Sep 17 00:00:00 2001
From: Ted Dunning <ted.dunning@gmail.com>
Date: Sun, 6 Aug 2017 13:49:10 -0700
Subject: [PATCH] Closes #90 - makes MergingDigest be consistent on
 serialization.

---
 RELEASE-NOTES.md                                     |  7 +++++++
 .../java/com/tdunning/math/stats/AVLTreeDigest.java  |  2 +-
 .../java/com/tdunning/math/stats/MergingDigest.java  | 12 ++++--------
 .../java/com/tdunning/math/stats/TDigestTest.java    |  2 +-
 4 files changed, 13 insertions(+), 10 deletions(-)
 create mode 100644 RELEASE-NOTES.md

diff --git a/RELEASE-NOTES.md b/RELEASE-NOTES.md
new file mode 100644
index 00000000..7b1f2a18
--- /dev/null
+++ b/RELEASE-NOTES.md
@@ -0,0 +1,7 @@
+In release 3.2
+
+The following issues are fixed in this release
+
+[Issue #90](https://github.com/tdunning/t-digest/issues/90) Serialization for MergingDigest
+
+[Issue #92](https://github.com/tdunning/t-digest/issues/92) Serialization for AVLTreeDigest
diff --git a/src/main/java/com/tdunning/math/stats/AVLTreeDigest.java b/src/main/java/com/tdunning/math/stats/AVLTreeDigest.java
index 2a56276f..a0824dc2 100644
--- a/src/main/java/com/tdunning/math/stats/AVLTreeDigest.java
+++ b/src/main/java/com/tdunning/math/stats/AVLTreeDigest.java
@@ -315,7 +315,7 @@ public double compression() {
      */
     @Override
     public int byteSize() {
-        return 4 + 8 * 2 + 8 + 4 + summary.size() * 12;
+        return 32 + summary.size() * 12;
     }
 
     /**
diff --git a/src/main/java/com/tdunning/math/stats/MergingDigest.java b/src/main/java/com/tdunning/math/stats/MergingDigest.java
index 8315cee5..68aa8d3e 100644
--- a/src/main/java/com/tdunning/math/stats/MergingDigest.java
+++ b/src/main/java/com/tdunning/math/stats/MergingDigest.java
@@ -753,7 +753,7 @@ public int byteSize() {
         compress();
         // format code, compression(float), buffer-size(int), temp-size(int), #centroids-1(int),
         // then two doubles per centroid
-        return lastUsedCell * 16 + 36;
+        return lastUsedCell * 16 + 32;
     }
 
     @Override
@@ -780,14 +780,10 @@ public void asBytes(ByteBuffer buf) {
         buf.putInt(Encoding.VERBOSE_ENCODING.code);
         buf.putDouble(min);
         buf.putDouble(max);
-        buf.putFloat((float) compression);
-        buf.putInt(mean.length);
-        buf.putInt(tempMean.length);
+        buf.putDouble(compression);
         buf.putInt(lastUsedCell);
         for (int i = 0; i < lastUsedCell; i++) {
             buf.putDouble(weight[i]);
-        }
-        for (int i = 0; i < lastUsedCell; i++) {
             buf.putDouble(mean[i]);
         }
     }
@@ -814,11 +810,11 @@ public static MergingDigest fromBytes(ByteBuffer buf) {
         if (encoding == Encoding.VERBOSE_ENCODING.code) {
             double min = buf.getDouble();
             double max = buf.getDouble();
-            double compression = buf.getFloat();
+            double compression = buf.getDouble();
             int n = buf.getInt();
             MergingDigest r = new MergingDigest(compression);
             r.setMinMax(min, max);
-            r.lastUsedCell = buf.getInt();
+            r.lastUsedCell = n;
             for (int i = 0; i < n; i++) {
                 r.weight[i] = buf.getDouble();
                 r.mean[i] = buf.getDouble();
diff --git a/src/test/java/com/tdunning/math/stats/TDigestTest.java b/src/test/java/com/tdunning/math/stats/TDigestTest.java
index 9a482b62..8fe29d11 100644
--- a/src/test/java/com/tdunning/math/stats/TDigestTest.java
+++ b/src/test/java/com/tdunning/math/stats/TDigestTest.java
@@ -612,7 +612,7 @@ public double nextDouble() {
     @Test
     public void testSerialization() {
         Random gen = getRandom();
-        final double compression = randomDouble() * 100;
+        final double compression = 20 + randomDouble() * 100;
         TDigest dist = factory(compression).create();
         for (int i = 0; i < 100000; i++) {
             double x = gen.nextDouble();