From e2d49922d22ced379efe31fbaf4a7c0601bd56f6 Mon Sep 17 00:00:00 2001
From: dellaert <dellaert@cc.gatech.edu>
Date: Sun, 21 Jun 2015 13:39:55 -0700
Subject: [PATCH] Switch to list - made code be container-agnostic

---
 gtsam/inference/ClusterTree-inst.h  | 19 +++++++------------
 gtsam/inference/ClusterTree.h       |  2 +-
 gtsam/inference/JunctionTree-inst.h | 11 +++++++----
 tests/testGaussianJunctionTreeB.cpp | 10 +++++-----
 4 files changed, 20 insertions(+), 22 deletions(-)

diff --git a/gtsam/inference/ClusterTree-inst.h b/gtsam/inference/ClusterTree-inst.h
index bbe878907..d777fcfe7 100644
--- a/gtsam/inference/ClusterTree-inst.h
+++ b/gtsam/inference/ClusterTree-inst.h
@@ -128,38 +128,32 @@ template<class BAYESTREE, class GRAPH>
 void ClusterTree<BAYESTREE, GRAPH>::Cluster::mergeChildren(
     const std::vector<bool>& merge) {
   gttic(Cluster::mergeChildren);
-  size_t nrChildren = children.size();
 
   // Count how many keys, factors and children we'll end up with
   size_t nrKeys = orderedFrontalKeys.size();
   size_t nrFactors = factors.size();
   size_t nrNewChildren = 0;
   // Loop over children
-  for (size_t i = 0; i < nrChildren; ++i) {
+  size_t i = 0;
+  BOOST_FOREACH(const sharedNode& child, children) {
     if (merge[i]) {
-      // Get a reference to the i, adjusting the index to account for children
-      // previously merged and removed from the i list.
-      sharedNode child = children[i];
       nrKeys += child->orderedFrontalKeys.size();
       nrFactors += child->factors.size();
       nrNewChildren += child->children.size();
     } else {
       nrNewChildren += 1; // we keep the child
     }
+    ++i;
   }
 
   // now reserve space, and really merge
   orderedFrontalKeys.reserve(nrKeys);
   factors.reserve(nrFactors);
   typename Node::Children newChildren;
-  newChildren.reserve(nrNewChildren);
-  // Loop over newChildren
-  for (size_t i = 0; i < nrChildren; ++i) {
-    // Check if we should merge the i^th child
-    sharedNode child = children[i];
+  // newChildren.reserve(nrNewChildren);
+  i = 0;
+  BOOST_FOREACH(const sharedNode& child, children) {
     if (merge[i]) {
-      // Get a reference to the i, adjusting the index to account for newChildren
-      // previously merged and removed from the i list.
       // Merge keys. For efficiency, we add keys in reverse order at end, calling reverse after..
       orderedFrontalKeys.insert(orderedFrontalKeys.end(),
           child->orderedFrontalKeys.rbegin(), child->orderedFrontalKeys.rend());
@@ -174,6 +168,7 @@ void ClusterTree<BAYESTREE, GRAPH>::Cluster::mergeChildren(
     } else {
       newChildren.push_back(child); // we keep the child
     }
+    ++i;
   }
   children = newChildren;
   std::reverse(orderedFrontalKeys.begin(), orderedFrontalKeys.end());
diff --git a/gtsam/inference/ClusterTree.h b/gtsam/inference/ClusterTree.h
index b00532d22..41232e1a1 100644
--- a/gtsam/inference/ClusterTree.h
+++ b/gtsam/inference/ClusterTree.h
@@ -37,7 +37,7 @@ public:
   struct Cluster {
     typedef Ordering Keys;
     typedef FastVector<sharedFactor> Factors;
-    typedef FastVector<boost::shared_ptr<Cluster> > Children;
+    typedef FastList<boost::shared_ptr<Cluster> > Children;
 
     Cluster() {
     }
diff --git a/gtsam/inference/JunctionTree-inst.h b/gtsam/inference/JunctionTree-inst.h
index 2df7aa930..352a8dded 100644
--- a/gtsam/inference/JunctionTree-inst.h
+++ b/gtsam/inference/JunctionTree-inst.h
@@ -104,15 +104,15 @@ struct ConstructorTraversalData {
 
     // decide which children to merge, as index into children
     std::vector<bool> merge(nrChildren, false);
-    size_t myNrFrontals = 1;
-    for (size_t i = 0; i < nrChildren; ++i) {
+    size_t myNrFrontals = 1, i = 0;
+    BOOST_FOREACH(const sharedNode& child, node->children) {
       // Check if we should merge the i^th child
       if (myNrParents + myNrFrontals == childConditionals[i]->nrParents()) {
-        sharedNode child = node->children[i];
         // Increment number of frontal variables
         myNrFrontals += child->orderedFrontalKeys.size();
         merge[i] = true;
       }
+      ++i;
     }
 
     // now really merge
@@ -145,7 +145,10 @@ JunctionTree<BAYESTREE, GRAPH>::JunctionTree(
       Data::ConstructorTraversalVisitorPostAlg2);
 
   // Assign roots from the dummy node
-  Base::roots_ = rootData.myJTNode->children;
+  typedef typename JunctionTree<BAYESTREE, GRAPH>::Node Node;
+  const typename Node::Children& children = rootData.myJTNode->children;
+  Base::roots_.reserve(children.size());
+  Base::roots_.insert(Base::roots_.begin(), children.begin(), children.end());
 
   // Transfer remaining factors from elimination tree
   Base::remainingFactors_ = eliminationTree.remainingFactors();
diff --git a/tests/testGaussianJunctionTreeB.cpp b/tests/testGaussianJunctionTreeB.cpp
index c5401512b..18d249894 100644
--- a/tests/testGaussianJunctionTreeB.cpp
+++ b/tests/testGaussianJunctionTreeB.cpp
@@ -103,15 +103,15 @@ TEST( GaussianJunctionTreeB, constructor2 )
   GaussianJunctionTree::sharedNode x324 = actual.roots().front();
   LONGS_EQUAL(2, x324->children.size());
 #if defined(__APPLE__) // tie-breaking seems different :-(
-  GaussianJunctionTree::sharedNode x1 = x324->children[0];
-  GaussianJunctionTree::sharedNode x56 = x324->children[1];
+  GaussianJunctionTree::sharedNode x1 = x324->children.front();
+  GaussianJunctionTree::sharedNode x56 = x324->children.back();
 #else
-  GaussianJunctionTree::sharedNode x1 = x324->children[1];
-  GaussianJunctionTree::sharedNode x56 = x324->children[0];
+  GaussianJunctionTree::sharedNode x1 = x324->children.back();
+  GaussianJunctionTree::sharedNode x56 = x324->children.front();
 #endif
   LONGS_EQUAL(0, x1->children.size());
   LONGS_EQUAL(1, x56->children.size());
-  GaussianJunctionTree::sharedNode x7 = x56->children[0];
+  GaussianJunctionTree::sharedNode x7 = x56->children.front();
   LONGS_EQUAL(0, x7->children.size());
 
   EXPECT(assert_equal(o324, x324->orderedFrontalKeys));