From 68d2f81f0a7624ea45b5437666d7a8f557af152b Mon Sep 17 00:00:00 2001
From: Frank Dellaert <dellaert@gmail.com>
Date: Sat, 31 Oct 2009 16:54:38 +0000
Subject: [PATCH] Smoother now creates x1...xT, not x0 anymore

---
 cpp/smallExample.cpp          | 12 ++++++------
 cpp/testLinearFactorGraph.cpp |  4 ++--
 cpp/timeLinearFactorGraph.cpp |  2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/cpp/smallExample.cpp b/cpp/smallExample.cpp
index 6123c829e..1b2a12028 100644
--- a/cpp/smallExample.cpp
+++ b/cpp/smallExample.cpp
@@ -245,14 +245,14 @@ LinearFactorGraph createSmoother(int T) {
 	ExampleNonlinearFactorGraph nlfg;
 	VectorConfig poses;
 
-	// prior on x0
-	Vector x0 = zero(2);
-	string key0 = symbol('x', 0);
-	shared prior(new Point2Prior(x0, 1, key0));
+	// prior on x1
+	Vector x1 = zero(2);
+	string key1 = symbol('x', 1);
+	shared prior(new Point2Prior(x1, 1, key1));
 	nlfg.push_back(prior);
-	poses.insert(key0, x0);
+	poses.insert(key1, x1);
 
-	for (int t = 1; t <= T; t++) {
+	for (int t = 2; t <= T; t++) {
 		// odometry between x_t and x_{t-1}
 		Vector odo = Vector_(2, 1.0, 0.0);
 		string key = symbol('x', t);
diff --git a/cpp/testLinearFactorGraph.cpp b/cpp/testLinearFactorGraph.cpp
index bb9d40747..549aa36d2 100644
--- a/cpp/testLinearFactorGraph.cpp
+++ b/cpp/testLinearFactorGraph.cpp
@@ -510,9 +510,9 @@ TEST( LinearFactorGraph, findAndRemoveFactors_twice )
 /* ************************************************************************* */
 TEST(timeLinearFactorGraph, createSmoother)
 {
-	LinearFactorGraph fg1 = createSmoother(1);
+	LinearFactorGraph fg1 = createSmoother(2);
 	LONGS_EQUAL(3,fg1.size());
-	LinearFactorGraph fg2 = createSmoother(2);
+	LinearFactorGraph fg2 = createSmoother(3);
 	LONGS_EQUAL(5,fg2.size());
 }
 
diff --git a/cpp/timeLinearFactorGraph.cpp b/cpp/timeLinearFactorGraph.cpp
index c91dd705a..19e54fe3e 100644
--- a/cpp/timeLinearFactorGraph.cpp
+++ b/cpp/timeLinearFactorGraph.cpp
@@ -16,7 +16,7 @@ using namespace gtsam;
 double timeKalmanSmoother(int T) {
 	LinearFactorGraph smoother = createSmoother(T);
 	Ordering ordering;
-	for (int t = 0; t <= T; t++) ordering.push_back(symbol('x',t));
+	for (int t = 1; t <= T; t++) ordering.push_back(symbol('x',t));
 	clock_t start = clock();
 	smoother.optimize(ordering);
 	clock_t end = clock ();