From 0d66ee8f72b5182bc13e88f194c2436dfea1c3a9 Mon Sep 17 00:00:00 2001
From: Frank Dellaert <dellaert@gmail.com>
Date: Thu, 15 Oct 2009 14:56:40 +0000
Subject: [PATCH] comments only

---
 .cproject                                | 18 ++----------------
 cpp/smallExample.cpp                     |  4 ++++
 cpp/testConstrainedLinearFactorGraph.cpp | 21 ++++++++++++++++-----
 3 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/.cproject b/.cproject
index 332430cf6..de1ddc75a 100644
--- a/.cproject
+++ b/.cproject
@@ -395,14 +395,6 @@
 <useDefaultCommand>true</useDefaultCommand>
 <runAllBuilders>true</runAllBuilders>
 </target>
-<target name="testLinearConstraint.run" path="cpp" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
-<buildCommand>make</buildCommand>
-<buildArguments/>
-<buildTarget>testLinearConstraint.run</buildTarget>
-<stopOnError>true</stopOnError>
-<useDefaultCommand>true</useDefaultCommand>
-<runAllBuilders>true</runAllBuilders>
-</target>
 <target name="testNonlinearFactorGraph.run" path="cpp" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
 <buildCommand>make</buildCommand>
 <buildArguments/>
@@ -418,14 +410,6 @@
 <useDefaultCommand>true</useDefaultCommand>
 <runAllBuilders>true</runAllBuilders>
 </target>
-<target name="testConstrainedConditionalGaussian.run" path="cpp" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
-<buildCommand>make</buildCommand>
-<buildArguments/>
-<buildTarget>testConstrainedConditionalGaussian.run</buildTarget>
-<stopOnError>true</stopOnError>
-<useDefaultCommand>true</useDefaultCommand>
-<runAllBuilders>true</runAllBuilders>
-</target>
 <target name="testConstrainedLinearFactorGraph.run" path="cpp" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
 <buildCommand>make</buildCommand>
 <buildArguments/>
@@ -436,6 +420,7 @@
 </target>
 <target name="install" path="" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
 <buildCommand>make</buildCommand>
+<buildArguments/>
 <buildTarget>install</buildTarget>
 <stopOnError>true</stopOnError>
 <useDefaultCommand>true</useDefaultCommand>
@@ -443,6 +428,7 @@
 </target>
 <target name="clean" path="" targetID="org.eclipse.cdt.build.MakeTargetBuilder">
 <buildCommand>make</buildCommand>
+<buildArguments/>
 <buildTarget>clean</buildTarget>
 <stopOnError>true</stopOnError>
 <useDefaultCommand>true</useDefaultCommand>
diff --git a/cpp/smallExample.cpp b/cpp/smallExample.cpp
index 80ac96f42..0a35299ba 100644
--- a/cpp/smallExample.cpp
+++ b/cpp/smallExample.cpp
@@ -241,6 +241,7 @@ ExampleNonlinearFactorGraph createReallyNonlinearFactorGraph() {
 /* ************************************************************************* */
 ConstrainedLinearFactorGraph createSingleConstraintGraph() {
 	// create unary factor
+	// prior on "x", mean = [1,-1], sigma=0.1
 	double sigma = 0.1;
 	Matrix Ax = eye(2) / sigma;
 	Vector b1(2);
@@ -249,6 +250,9 @@ ConstrainedLinearFactorGraph createSingleConstraintGraph() {
 	LinearFactor::shared_ptr f1(new LinearFactor("x", Ax, b1 / sigma));
 
 	// create binary constraint factor
+	// between "x" and "y", that is going to be the only factor on "y"
+	// |1 2||x_1| + |10 0||y_1| = |1|
+	// |2 1||x_2|   |0 10||y_2|   |2|
 	Matrix Ax1(2, 2);
 	Ax1(0, 0) = 1.0; Ax1(0, 1) = 2.0;
 	Ax1(1, 0) = 2.0; Ax1(1, 1) = 1.0;
diff --git a/cpp/testConstrainedLinearFactorGraph.cpp b/cpp/testConstrainedLinearFactorGraph.cpp
index 4370c4412..14289faa1 100644
--- a/cpp/testConstrainedLinearFactorGraph.cpp
+++ b/cpp/testConstrainedLinearFactorGraph.cpp
@@ -16,6 +16,7 @@ using namespace std;
 TEST( ConstrainedLinearFactorGraph, elimination1 )
 {
 	// get the graph
+	// *-X-x-Y
 	ConstrainedLinearFactorGraph fg = createSingleConstraintGraph();
 
 	// verify construction of the graph
@@ -26,9 +27,14 @@ TEST( ConstrainedLinearFactorGraph, elimination1 )
 	ord.push_back("x");
 	ChordalBayesNet::shared_ptr cbn = fg.eliminate(ord);
 
-	//verify changes and output
+	// verify result of elimination
+	// CBN of size 1, as we only eliminated X now
 	CHECK(fg.size() == 1);
 	CHECK(cbn->size() == 1);
+
+	// We will have a "delta function" on X as a function of Y
+	// |1 2||x_1| = |1| - |10 0||y_1|
+	// |2 1||x_2|   |2|   |0 10||y_2|
 	Matrix Ax1(2, 2);
 	Ax1(0, 0) = 1.0; Ax1(0, 1) = 2.0;
 	Ax1(1, 0) = 2.0; Ax1(1, 1) = 1.0;
@@ -36,6 +42,9 @@ TEST( ConstrainedLinearFactorGraph, elimination1 )
 	Vector b2 = Vector_(2, 1.0, 2.0);
 	ConstrainedConditionalGaussian expectedCCG1(b2, Ax1, "y", Ay1);
 	CHECK(expectedCCG1.equals(*(cbn->get("x"))));
+
+	// verify remaining factor on y
+	// Gaussian factor on X becomes different Gaussian factor on Y
 	Matrix Ap(2,2);
 	Ap(0, 0) =  1.0; Ap(0, 1) = -2.0;
 	Ap(1, 0) = -2.0; Ap(1, 1) =  1.0;
@@ -48,12 +57,14 @@ TEST( ConstrainedLinearFactorGraph, elimination1 )
 	Ordering ord2;
 	ord2.push_back("y");
 	cbn = fg.eliminate(ord2);
+
+	// Check result
 	CHECK(fg.size() == 0);
-	Matrix Ar(2,2);
-	Ar(0, 0) = 74.5356; Ar(0, 1) = -59.6285;
-	Ar(1, 0) = 0.0;     Ar(1, 1) = 44.7214;
+	Matrix R(2,2);
+	R(0, 0) = 74.5356; R(0, 1) = -59.6285;
+	R(1, 0) = 0.0;     R(1, 1) = 44.7214;
 	Vector br = Vector_(2, 8.9443, 4.4721);
-	ConditionalGaussian expected2(br, Ar);
+	ConditionalGaussian expected2(br, R);
 	CHECK(expected2.equals(*(cbn->get("y"))));
 }