From ed616a26eda086e931474bb500ad843932bd775d Mon Sep 17 00:00:00 2001
From: Frank Dellaert <dellaert@gmail.com>
Date: Sun, 18 Oct 2009 16:49:10 +0000
Subject: [PATCH] Finally gave in and made LinearFactorSet into a vector.
 Pragmatism wins.

---
 cpp/LinearFactor.cpp      |  2 +-
 cpp/LinearFactor.h        |  5 +----
 cpp/LinearFactorGraph.cpp |  4 ++--
 cpp/LinearFactorGraph.h   |  1 -
 cpp/LinearFactorSet.h     |  3 ++-
 cpp/testLinearFactor.cpp  | 20 ++++++++------------
 6 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/cpp/LinearFactor.cpp b/cpp/LinearFactor.cpp
index 72134546d..20a3b4bd1 100644
--- a/cpp/LinearFactor.cpp
+++ b/cpp/LinearFactor.cpp
@@ -149,7 +149,7 @@ void MutableLinearFactor::append_factor(LinearFactor::shared_ptr f, const size_t
 }
 
 /* ************************************************************************* */
-MutableLinearFactor::MutableLinearFactor(const set<shared_ptr> & factors)
+MutableLinearFactor::MutableLinearFactor(const vector<shared_ptr> & factors)
 {
   // Create RHS vector of the right size by adding together row counts
   size_t m = 0;
diff --git a/cpp/LinearFactor.h b/cpp/LinearFactor.h
index dcec35345..ff4f7a55e 100644
--- a/cpp/LinearFactor.h
+++ b/cpp/LinearFactor.h
@@ -187,13 +187,10 @@ public:
 
 	/**
 	 * Constructor that combines a set of factors
-	 * NOTE: the combined factor will be depends on a system-dependent
-	 * ordering of the input set of factors.  Do not rely on this order
-	 * when using the function.
 	 * @param factors Set of factors to combine
 	 */
 	CONSTRUCTOR
-	MutableLinearFactor(const std::set<shared_ptr> & factors);
+	MutableLinearFactor(const std::vector<shared_ptr> & factors);
 
 	/** Construct unary mutable factor */
 	CONSTRUCTOR
diff --git a/cpp/LinearFactorGraph.cpp b/cpp/LinearFactorGraph.cpp
index 478a122a1..94f42b20a 100644
--- a/cpp/LinearFactorGraph.cpp
+++ b/cpp/LinearFactorGraph.cpp
@@ -57,7 +57,7 @@ LinearFactorGraph::find_factors_and_remove(const string& key)
 
 	for(iterator factor=factors_.begin(); factor!=factors_.end(); )
 		if ((*factor)->involves(key)) {
-			found.insert(*factor);
+			found.push_back(*factor);
 			factor = factors_.erase(factor);
 		} else {
 			factor++; // important, erase will have effect of ++
@@ -219,7 +219,7 @@ pair<Matrix,Vector> LinearFactorGraph::matrix(const Ordering& ordering) const {
 	// get all factors
 	LinearFactorSet found;
 	BOOST_FOREACH(shared_factor factor,factors_)
-		found.insert(factor);
+		found.push_back(factor);
 
 	// combine them
 	MutableLinearFactor lf(found);
diff --git a/cpp/LinearFactorGraph.h b/cpp/LinearFactorGraph.h
index 859d03744..36aed3251 100644
--- a/cpp/LinearFactorGraph.h
+++ b/cpp/LinearFactorGraph.h
@@ -15,7 +15,6 @@
 #include <boost/shared_ptr.hpp>
 
 #include "LinearFactor.h"
-//#include "Ordering.h"
 #include "VectorConfig.h"
 #include "FactorGraph.h"
 
diff --git a/cpp/LinearFactorSet.h b/cpp/LinearFactorSet.h
index 30e2f0f67..4f1c0f506 100644
--- a/cpp/LinearFactorSet.h
+++ b/cpp/LinearFactorSet.h
@@ -14,7 +14,8 @@ namespace gtsam {
   
   class LinearFactor;
   
-  struct LinearFactorSet : std::set<boost::shared_ptr<LinearFactor> > {
+  // We use a vector not a an STL set, to get predictable ordering across platforms
+  struct LinearFactorSet : std::vector<boost::shared_ptr<LinearFactor> > {
     LinearFactorSet() {}
   };
 }
diff --git a/cpp/testLinearFactor.cpp b/cpp/testLinearFactor.cpp
index c418b1be6..af5c3192d 100644
--- a/cpp/testLinearFactor.cpp
+++ b/cpp/testLinearFactor.cpp
@@ -64,19 +64,15 @@ TEST( LinearFactor, variables )
 }
 
 /* ************************************************************************* */
-
-// NOTE: This test fails due to order dependency in the extraction of factors
-//       To fix it, it will be necessary to construct the expected version
-//       of the combined factor taking into account the ordering in the set
 TEST( LinearFactor, linearFactor2 )
 {
   // create a small linear factor graph
   LinearFactorGraph fg = createLinearFactorGraph();
 
   // get two factors from it and insert the factors into a set
-  std::set<LinearFactor::shared_ptr> lfg;
-  lfg.insert(fg[4 - 1]);
-  lfg.insert(fg[2 - 1]);
+  vector<LinearFactor::shared_ptr> lfg;
+  lfg.push_back(fg[4 - 1]);
+  lfg.push_back(fg[2 - 1]);
 
   // combine in a factor
   MutableLinearFactor combined(lfg);
@@ -137,11 +133,11 @@ TEST( NonlinearFactorGraph, linearFactor3){
 	b(0) = 5 ; b(1) = -6;
 	LinearFactor::shared_ptr f4(new LinearFactor("x1", A11, b));
 
-	std::set<LinearFactor::shared_ptr> lfg;
-	lfg.insert(f1);
-	lfg.insert(f2);
-	lfg.insert(f3);
-	lfg.insert(f4);
+	vector<LinearFactor::shared_ptr> lfg;
+	lfg.push_back(f1);
+	lfg.push_back(f2);
+	lfg.push_back(f3);
+	lfg.push_back(f4);
 	MutableLinearFactor combined(lfg);
 
 	Matrix A22(8,2);