gtsam/cpp/testBayesTree.cpp

315 lines
11 KiB
C++

/**
* @file testBayesTree.cpp
* @brief Unit tests for Bayes Tree
* @author Frank Dellaert
*/
#include <boost/assign/std/list.hpp> // for operator +=
using namespace boost::assign;
#include <CppUnitLite/TestHarness.h>
#include "SymbolicBayesNet.h"
#include "GaussianBayesNet.h"
#include "Ordering.h"
#include "BayesTree-inl.h"
#include "smallExample.h"
using namespace gtsam;
typedef BayesTree<ConditionalGaussian> Gaussian;
// Conditionals for ASIA example from the tutorial with A and D evidence
SymbolicConditional::shared_ptr B(new SymbolicConditional("B")), L(
new SymbolicConditional("L", "B")), E(
new SymbolicConditional("E", "L", "B")), S(new SymbolicConditional("S",
"L", "B")), T(new SymbolicConditional("T", "E", "L")), X(
new SymbolicConditional("X", "E"));
/* ************************************************************************* */
TEST( BayesTree, Front )
{
SymbolicBayesNet f1;
f1.push_back(B);
f1.push_back(L);
SymbolicBayesNet f2;
f2.push_back(L);
f2.push_back(B);
CHECK(f1.equals(f1));
CHECK(!f1.equals(f2));
}
/* ************************************************************************* */
TEST( BayesTree, constructor )
{
// Create using insert
BayesTree<SymbolicConditional> bayesTree;
bayesTree.insert(B);
bayesTree.insert(L);
bayesTree.insert(E);
bayesTree.insert(S);
bayesTree.insert(T);
bayesTree.insert(X);
// Check Size
LONGS_EQUAL(6,bayesTree.size());
// Check root
BayesNet<SymbolicConditional> expected_root;
expected_root.push_back(E);
expected_root.push_back(L);
expected_root.push_back(B);
boost::shared_ptr<BayesNet<SymbolicConditional> > actual_root = bayesTree.root();
CHECK(assert_equal(expected_root,*actual_root));
// Create from symbolic Bayes chain in which we want to discover cliques
SymbolicBayesNet ASIA;
ASIA.push_back(X);
ASIA.push_back(T);
ASIA.push_back(S);
ASIA.push_back(E);
ASIA.push_back(L);
ASIA.push_back(B);
BayesTree<SymbolicConditional> bayesTree2(ASIA);
//bayesTree2.print("bayesTree2");
// Check whether the same
CHECK(assert_equal(bayesTree,bayesTree2));
}
/* ************************************************************************* */
// Some numbers that should be consistent among all smoother tests
double sigmax1 = 0.786153, sigmax2 = 0.687131, sigmax3 = 0.671512, sigmax4 =
0.669534, sigmax5 = sigmax3, sigmax6 = sigmax2, sigmax7 = sigmax1;
/* ************************************************************************* *
Bayes tree for smoother with "natural" ordering:
C1 x6 x7
C2 x5 : x6
C3 x4 : x5
C4 x3 : x4
C5 x2 : x3
C6 x1 : x2
/* ************************************************************************* */
TEST( BayesTree, linear_smoother_shortcuts )
{
// Create smoother with 7 nodes
LinearFactorGraph smoother = createSmoother(7);
Ordering ordering;
for (int t = 1; t <= 7; t++)
ordering.push_back(symbol('x', t));
// eliminate using the "natural" ordering
GaussianBayesNet chordalBayesNet = smoother.eliminate(ordering);
// Create the Bayes tree
Gaussian bayesTree(chordalBayesNet);
LONGS_EQUAL(7,bayesTree.size());
// Check the conditional P(Root|Root)
GaussianBayesNet empty;
Gaussian::sharedClique R = bayesTree.root();
GaussianBayesNet actual1 = R->shortcut<LinearFactor>(R);
CHECK(assert_equal(empty,actual1,1e-4));
// Check the conditional P(C2|Root)
Gaussian::sharedClique C2 = bayesTree["x5"];
GaussianBayesNet actual2 = C2->shortcut<LinearFactor>(R);
CHECK(assert_equal(empty,actual2,1e-4));
// Check the conditional P(C3|Root)
Vector sigma3 = repeat(2, 0.61808);
Matrix A56 = Matrix_(2,2,-0.382022,0.,0.,-0.382022);
ConditionalGaussian::shared_ptr cg3(new ConditionalGaussian("x5", zero(2), eye(2), "x6", A56, sigma3));
GaussianBayesNet expected3; expected3.push_back(cg3);
Gaussian::sharedClique C3 = bayesTree["x4"];
GaussianBayesNet actual3 = C3->shortcut<LinearFactor>(R);
CHECK(assert_equal(expected3,actual3,1e-4));
// Check the conditional P(C4|Root)
Vector sigma4 = repeat(2, 0.661968);
Matrix A46 = Matrix_(2,2,-0.146067,0.,0.,-0.146067);
ConditionalGaussian::shared_ptr cg4(new ConditionalGaussian("x4", zero(2), eye(2), "x6", A46, sigma4));
GaussianBayesNet expected4; expected4.push_back(cg4);
Gaussian::sharedClique C4 = bayesTree["x3"];
GaussianBayesNet actual4 = C4->shortcut<LinearFactor>(R);
CHECK(assert_equal(expected4,actual4,1e-4));
}
/* ************************************************************************* *
Bayes tree for smoother with "nested dissection" ordering:
Node[x1] P(x1 | x2)
Node[x3] P(x3 | x2 x4)
Node[x5] P(x5 | x4 x6)
Node[x7] P(x7 | x6)
Node[x2] P(x2 | x4)
Node[x6] P(x6 | x4)
Node[x4] P(x4)
becomes
C1 x5 x6 x4
C2 x3 x2 : x4
C3 x1 : x2
C4 x7 : x6
/* ************************************************************************* */
TEST( BayesTree, balanced_smoother_marginals )
{
// Create smoother with 7 nodes
LinearFactorGraph smoother = createSmoother(7);
Ordering ordering;
ordering += "x1","x3","x5","x7","x2","x6","x4";
// eliminate using a "nested dissection" ordering
GaussianBayesNet chordalBayesNet = smoother.eliminate(ordering);
VectorConfig expectedSolution;
BOOST_FOREACH(string key, ordering)
expectedSolution.insert(key,zero(2));
VectorConfig actualSolution = optimize(chordalBayesNet);
CHECK(assert_equal(expectedSolution,actualSolution,1e-4));
// Create the Bayes tree
Gaussian bayesTree(chordalBayesNet);
LONGS_EQUAL(7,bayesTree.size());
// Check marginal on x1
GaussianBayesNet expected1 = simpleGaussian("x1", zero(2), sigmax1);
GaussianBayesNet actual1 = bayesTree.marginalBayesNet<LinearFactor>("x1");
CHECK(assert_equal(expected1,actual1,1e-4));
// Check marginal on x2
GaussianBayesNet expected2 = simpleGaussian("x2", zero(2), sigmax2);
GaussianBayesNet actual2 = bayesTree.marginalBayesNet<LinearFactor>("x2");
CHECK(assert_equal(expected2,actual2,1e-4));
// Check marginal on x3
GaussianBayesNet expected3 = simpleGaussian("x3", zero(2), sigmax3);
GaussianBayesNet actual3 = bayesTree.marginalBayesNet<LinearFactor>("x3");
CHECK(assert_equal(expected3,actual3,1e-4));
// Check marginal on x4
GaussianBayesNet expected4 = simpleGaussian("x4", zero(2), sigmax4);
GaussianBayesNet actual4 = bayesTree.marginalBayesNet<LinearFactor>("x4");
CHECK(assert_equal(expected4,actual4,1e-4));
// Check marginal on x7 (should be equal to x1)
GaussianBayesNet expected7 = simpleGaussian("x7", zero(2), sigmax7);
GaussianBayesNet actual7 = bayesTree.marginalBayesNet<LinearFactor>("x7");
CHECK(assert_equal(expected7,actual7,1e-4));
}
/* ************************************************************************* */
TEST( BayesTree, balanced_smoother_shortcuts )
{
// Create smoother with 7 nodes
LinearFactorGraph smoother = createSmoother(7);
Ordering ordering;
ordering += "x1","x3","x5","x7","x2","x6","x4";
// Create the Bayes tree
GaussianBayesNet chordalBayesNet = smoother.eliminate(ordering);
Gaussian bayesTree(chordalBayesNet);
// Check the conditional P(Root|Root)
GaussianBayesNet empty;
Gaussian::sharedClique R = bayesTree.root();
GaussianBayesNet actual1 = R->shortcut<LinearFactor>(R);
CHECK(assert_equal(empty,actual1,1e-4));
// Check the conditional P(C2|Root)
Gaussian::sharedClique C2 = bayesTree["x3"];
GaussianBayesNet actual2 = C2->shortcut<LinearFactor>(R);
CHECK(assert_equal(empty,actual2,1e-4));
// Check the conditional P(C3|Root), which should be equal to P(x2|x4)
ConditionalGaussian::shared_ptr p_x2_x4 = chordalBayesNet["x2"];
GaussianBayesNet expected3; expected3.push_back(p_x2_x4);
Gaussian::sharedClique C3 = bayesTree["x1"];
GaussianBayesNet actual3 = C3->shortcut<LinearFactor>(R);
CHECK(assert_equal(expected3,actual3,1e-4));
}
/* ************************************************************************* */
TEST( BayesTree, balanced_smoother_clique_marginals )
{
// Create smoother with 7 nodes
LinearFactorGraph smoother = createSmoother(7);
Ordering ordering;
ordering += "x1","x3","x5","x7","x2","x6","x4";
// Create the Bayes tree
GaussianBayesNet chordalBayesNet = smoother.eliminate(ordering);
Gaussian bayesTree(chordalBayesNet);
// Check the clique marginal P(C3)
GaussianBayesNet expected = simpleGaussian("x2",zero(2),sigmax2);
Vector sigma = repeat(2, 0.707107);
Matrix A12 = (-0.5)*eye(2);
ConditionalGaussian::shared_ptr cg(new ConditionalGaussian("x1", zero(2), eye(2), "x2", A12, sigma));
expected.push_front(cg);
Gaussian::sharedClique R = bayesTree.root(), C3 = bayesTree["x1"];
FactorGraph<LinearFactor> marginal = C3->marginal<LinearFactor>(R);
GaussianBayesNet actual = eliminate<LinearFactor,ConditionalGaussian>(marginal,C3->keys());
CHECK(assert_equal(expected,actual,1e-4));
}
/* ************************************************************************* */
TEST( BayesTree, balanced_smoother_joint )
{
// Create smoother with 7 nodes
LinearFactorGraph smoother = createSmoother(7);
Ordering ordering;
ordering += "x1","x3","x5","x7","x2","x6","x4";
// Create the Bayes tree
GaussianBayesNet chordalBayesNet = smoother.eliminate(ordering);
Gaussian bayesTree(chordalBayesNet);
// Conditional density elements reused by both tests
Vector sigma = repeat(2, 0.786146);
Matrix A = (-0.00429185)*eye(2);
// Check the joint density P(x1,x7) factored as P(x1|x7)P(x7)
GaussianBayesNet expected1 = simpleGaussian("x7", zero(2), sigmax7);
ConditionalGaussian::shared_ptr cg1(new ConditionalGaussian("x1", zero(2), eye(2), "x7", A, sigma));
expected1.push_front(cg1);
GaussianBayesNet actual1 = bayesTree.jointBayesNet<LinearFactor>("x1","x7");
CHECK(assert_equal(expected1,actual1,1e-4));
// Check the joint density P(x7,x1) factored as P(x7|x1)P(x1)
GaussianBayesNet expected2 = simpleGaussian("x1", zero(2), sigmax1);
ConditionalGaussian::shared_ptr cg2(new ConditionalGaussian("x7", zero(2), eye(2), "x1", A, sigma));
expected2.push_front(cg2);
GaussianBayesNet actual2 = bayesTree.jointBayesNet<LinearFactor>("x7","x1");
CHECK(assert_equal(expected2,actual2,1e-4));
// Check the joint density P(x1,x4), i.e. with a root variable
GaussianBayesNet expected3 = simpleGaussian("x4", zero(2), sigmax4);
Vector sigma14 = repeat(2, 0.784465);
Matrix A14 = (-0.0769231)*eye(2);
ConditionalGaussian::shared_ptr cg3(new ConditionalGaussian("x1", zero(2), eye(2), "x4", A14, sigma14));
expected3.push_front(cg3);
GaussianBayesNet actual3 = bayesTree.jointBayesNet<LinearFactor>("x1","x4");
CHECK(assert_equal(expected3,actual3,1e-4));
// Check the joint density P(x4,x1), i.e. with a root variable, factored the other way
GaussianBayesNet expected4 = simpleGaussian("x1", zero(2), sigmax1);
Vector sigma41 = repeat(2, 0.668096);
Matrix A41 = (-0.055794)*eye(2);
ConditionalGaussian::shared_ptr cg4(new ConditionalGaussian("x4", zero(2), eye(2), "x1", A41, sigma41));
expected4.push_front(cg4);
GaussianBayesNet actual4 = bayesTree.jointBayesNet<LinearFactor>("x4","x1");
CHECK(assert_equal(expected4,actual4,1e-4));
}
/* ************************************************************************* */
int main() {
TestResult tr;
return TestRegistry::runAllTests(tr);
}
/* ************************************************************************* */