From 42fda7913f125ef441d845285afc94f96302a47d Mon Sep 17 00:00:00 2001
From: Frank Dellaert <dellaert@gmail.com>
Date: Sat, 26 Oct 2013 15:25:56 +0000
Subject: [PATCH] Added path compression

---
 gtsam/base/DSFVector.cpp | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/gtsam/base/DSFVector.cpp b/gtsam/base/DSFVector.cpp
index 24ac9b9e1..61e878e70 100644
--- a/gtsam/base/DSFVector.cpp
+++ b/gtsam/base/DSFVector.cpp
@@ -43,12 +43,11 @@ DSFBase::DSFBase(const boost::shared_ptr<V>& v_in) {
 
 /* ************************************************************************* */
 size_t DSFBase::findSet(size_t key) const {
-  size_t parent = (*v_)[key];
   // follow parent pointers until we reach set representative
-  while (parent != key) {
-    key = parent;
-    parent = (*v_)[key];
-  }
+  size_t parent = (*v_)[key];
+  if (parent != key)
+    parent = findSet(parent); // recursive call
+  (*v_)[key] = parent; // path compression
   return parent;
 }