testDiscreteFactorGraph.cpp

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/* ----------------------------------------------------------------------------

 * GTSAM Copyright 2010, Georgia Tech Research Corporation,
 * Atlanta, Georgia 30332-0415
 * All Rights Reserved
 * Authors: Frank Dellaert, et al. (see THANKS for the full author list)

 * See LICENSE for the license information

 * -------------------------------------------------------------------------- */

/*
 *  @file testDiscreteFactorGraph.cpp
 *  @date Feb 14, 2011
 *  @author Duy-Nguyen Ta
 */

#include <gtsam/discrete/DiscreteFactor.h>
#include <gtsam/discrete/DiscreteFactorGraph.h>
#include <gtsam/discrete/DiscreteEliminationTree.h>
#include <gtsam/discrete/DiscreteBayesTree.h>
#include <gtsam/inference/BayesNet.h>

#include <CppUnitLite/TestHarness.h>

#include <boost/assign/std/map.hpp>
using namespace boost::assign;

using namespace std;
using namespace gtsam;

/* ************************************************************************* */
TEST_UNSAFE( DiscreteFactorGraph, debugScheduler) {
  DiscreteKey PC(0,4), ME(1, 4), AI(2, 4), A(3, 3);

  DiscreteFactorGraph graph;
  graph.add(AI, "1 0 0 1");
  graph.add(AI, "1 1 1 0");
  graph.add(A & AI, "1 1 1 0   1 1 1 1   0 1 1 1");
  graph.add(ME, "0 1 0 0");
  graph.add(ME, "1 1 1 0");
  graph.add(A & ME, "1 1 1 0   1 1 1 1   0 1 1 1");
  graph.add(PC, "1 0 1 0");
  graph.add(PC, "1 1 1 0");
  graph.add(A & PC, "1 1 1 0   1 1 1 1   0 1 1 1");
  graph.add(ME & AI, "0 1 1 1   1 0 1 1   1 1 0 1  1 1 1 0");
  graph.add(PC & ME, "0 1 1 1   1 0 1 1   1 1 0 1  1 1 1 0");
  graph.add(PC & AI, "0 1 1 1   1 0 1 1   1 1 0 1  1 1 1 0");

//  graph.print("Graph: ");
  DecisionTreeFactor product = graph.product();
  DecisionTreeFactor::shared_ptr sum = product.sum(1);
//  sum->print("Debug SUM: ");
  DiscreteConditional::shared_ptr cond(new DiscreteConditional(product, *sum));

//  cond->print("marginal:");

//  pair<DiscreteBayesNet::shared_ptr, DiscreteFactor::shared_ptr> result = EliminateDiscrete(graph, 1);
//  result.first->print("BayesNet: ");
//  result.second->print("New factor: ");
//
  Ordering ordering;
  ordering += Key(0),Key(1),Key(2),Key(3);
  DiscreteEliminationTree eliminationTree(graph, ordering);
//  eliminationTree.print("Elimination tree: ");
  eliminationTree.eliminate(EliminateDiscrete);
//  solver.optimize();
//  DiscreteBayesNet::shared_ptr bayesNet = solver.eliminate();
}

/* ************************************************************************* */
TEST_UNSAFE( DiscreteFactorGraph, DiscreteFactorGraphEvaluationTest) {

  // Three keys P1 and P2
  DiscreteKey P1(0,2), P2(1,2), P3(2,3);

  // Create the DiscreteFactorGraph
  DiscreteFactorGraph graph;
  graph.add(P1, "0.9 0.3");
  graph.add(P2, "0.9 0.6");
  graph.add(P1 & P2, "4 1 10 4");

  // Instantiate Values
  DiscreteFactor::Values values;
  values[0] = 1;
  values[1] = 1;

  // Check if graph evaluation works ( 0.3*0.6*4 )
  EXPECT_DOUBLES_EQUAL( .72, graph(values), 1e-9);

  // Creating a new test with third node and adding unary and ternary factors on it
  graph.add(P3, "0.9 0.2 0.5");
  graph.add(P1 & P2 & P3, "1 2 3 4 5 6 7 8 9 10 11 12");

  // Below values lead to selecting the 8th index in the ternary factor table
  values[0] = 1;
  values[1] = 0;
  values[2] = 1;

  // Check if graph evaluation works (0.3*0.9*1*0.2*8)
  EXPECT_DOUBLES_EQUAL( 4.32, graph(values), 1e-9);

  // Below values lead to selecting the 3rd index in the ternary factor table
  values[0] = 0;
  values[1] = 1;
  values[2] = 0;

  // Check if graph evaluation works (0.9*0.6*1*0.9*4)
  EXPECT_DOUBLES_EQUAL( 1.944, graph(values), 1e-9);

  // Check if graph product works
  DecisionTreeFactor product = graph.product();
  EXPECT_DOUBLES_EQUAL( 1.944, product(values), 1e-9);
}

/* ************************************************************************* */
TEST( DiscreteFactorGraph, test)
{
  // Declare keys and ordering
  DiscreteKey C(0,2), B(1,2), A(2,2);

  // A simple factor graph (A)-fAC-(C)-fBC-(B)
  // with smoothness priors
  DiscreteFactorGraph graph;
  graph.add(A & C, "3 1 1 3");
  graph.add(C & B, "3 1 1 3");

  // Test EliminateDiscrete
  // FIXME: apparently Eliminate returns a conditional rather than a net
  Ordering frontalKeys;
  frontalKeys += Key(0);
  DiscreteConditional::shared_ptr conditional;
  DecisionTreeFactor::shared_ptr newFactor;
  boost::tie(conditional, newFactor) = EliminateDiscrete(graph, frontalKeys);

  // Check Bayes net
  CHECK(conditional);
  DiscreteBayesNet expected;
  Signature signature((C | B, A) = "9/1 1/1 1/1 1/9");
  // cout << signature << endl;
  DiscreteConditional expectedConditional(signature);
  EXPECT(assert_equal(expectedConditional, *conditional));
  expected.add(signature);

  // Check Factor
  CHECK(newFactor);
  DecisionTreeFactor expectedFactor(B & A, "10 6 6 10");
  EXPECT(assert_equal(expectedFactor, *newFactor));

  // add conditionals to complete expected Bayes net
  expected.add(B | A = "5/3 3/5");
  expected.add(A % "1/1");
  //  GTSAM_PRINT(expected);

  // Test elimination tree
  Ordering ordering;
  ordering += Key(0), Key(1), Key(2);
  DiscreteEliminationTree etree(graph, ordering);
  DiscreteBayesNet::shared_ptr actual;
  DiscreteFactorGraph::shared_ptr remainingGraph;
  boost::tie(actual, remainingGraph) = etree.eliminate(&EliminateDiscrete);
  EXPECT(assert_equal(expected, *actual));

//  // Test solver
//  DiscreteBayesNet::shared_ptr actual2 = solver.eliminate();
//  EXPECT(assert_equal(expected, *actual2));

  // Test optimization
  DiscreteFactor::Values expectedValues;
  insert(expectedValues)(0, 0)(1, 0)(2, 0);
  DiscreteFactor::sharedValues actualValues = graph.optimize();
  EXPECT(assert_equal(expectedValues, *actualValues));
}

/* ************************************************************************* */
TEST( DiscreteFactorGraph, testMPE)
{
  // Declare a bunch of keys
  DiscreteKey C(0,2), A(1,2), B(2,2);

  // Create Factor graph
  DiscreteFactorGraph graph;
  graph.add(C & A, "0.2 0.8 0.3 0.7");
  graph.add(C & B, "0.1 0.9 0.4 0.6");
  //  graph.product().print();
  //  DiscreteSequentialSolver(graph).eliminate()->print();

  DiscreteFactor::sharedValues actualMPE = graph.optimize();

  DiscreteFactor::Values expectedMPE;
  insert(expectedMPE)(0, 0)(1, 1)(2, 1);
  EXPECT(assert_equal(expectedMPE, *actualMPE));
}

/* ************************************************************************* */
TEST( DiscreteFactorGraph, testMPE_Darwiche09book_p244)
{
  // The factor graph in Darwiche09book, page 244
  DiscreteKey A(4,2), C(3,2), S(2,2), T1(0,2), T2(1,2);

  // Create Factor graph
  DiscreteFactorGraph graph;
  graph.add(S, "0.55 0.45");
  graph.add(S & C, "0.05 0.95 0.01 0.99");
  graph.add(C & T1, "0.80 0.20 0.20 0.80");
  graph.add(S & C & T2, "0.80 0.20 0.20 0.80 0.95 0.05 0.05 0.95");
  graph.add(T1 & T2 & A, "1 0 0 1 0 1 1 0");
  graph.add(A, "1 0");// evidence, A = yes (first choice in Darwiche)
  //graph.product().print("Darwiche-product");
  //  graph.product().potentials().dot("Darwiche-product");
  //  DiscreteSequentialSolver(graph).eliminate()->print();

  DiscreteFactor::Values expectedMPE;
  insert(expectedMPE)(4, 0)(2, 0)(3, 1)(0, 1)(1, 1);

  // Use the solver machinery.
  DiscreteBayesNet::shared_ptr chordal = graph.eliminateSequential();
  DiscreteFactor::sharedValues actualMPE = chordal->optimize();
  EXPECT(assert_equal(expectedMPE, *actualMPE));
//  DiscreteConditional::shared_ptr root = chordal->back();
//  EXPECT_DOUBLES_EQUAL(0.4, (*root)(*actualMPE), 1e-9);

  // Let us create the Bayes tree here, just for fun, because we don't use it now
//  typedef JunctionTreeOrdered<DiscreteFactorGraph> JT;
//  GenericMultifrontalSolver<DiscreteFactor, JT> solver(graph);
//  BayesTreeOrdered<DiscreteConditional>::shared_ptr bayesTree = solver.eliminate(&EliminateDiscrete);
//  EXPECT_LONGS_EQUAL(2,bayesTree->size());

  Ordering ordering;
  ordering += Key(0),Key(1),Key(2),Key(3),Key(4);
  DiscreteBayesTree::shared_ptr bayesTree = graph.eliminateMultifrontal(ordering);
  //  bayesTree->print("Bayes Tree");
  EXPECT_LONGS_EQUAL(2,bayesTree->size());

#ifdef OLD
// Create the elimination tree manually
VariableIndexOrdered structure(graph);
typedef EliminationTreeOrdered<DiscreteFactor> ETree;
ETree::shared_ptr eTree = ETree::Create(graph, structure);
//eTree->print(">>>>>>>>>>> Elimination Tree <<<<<<<<<<<<<<<<<");

// eliminate normally and check solution
DiscreteBayesNet::shared_ptr bayesNet = eTree->eliminate(&EliminateDiscrete);
//  bayesNet->print(">>>>>>>>>>>>>> Bayes Net <<<<<<<<<<<<<<<<<<");
DiscreteFactor::sharedValues actualMPE = optimize(*bayesNet);
EXPECT(assert_equal(expectedMPE, *actualMPE));

// Approximate and check solution
//  DiscreteBayesNet::shared_ptr approximateNet = eTree->approximate();
//  approximateNet->print(">>>>>>>>>>>>>> Approximate Net <<<<<<<<<<<<<<<<<<");
//  EXPECT(assert_equal(expectedMPE, *actualMPE));
#endif
}
#ifdef OLD

/* ************************************************************************* */
class Key2 {
private:
std::string wff_;
size_t cardinality_;
public:
Key2(const std::string& name, size_t cardinality = 2) :
wff_(name), cardinality_(cardinality) {
}
const std::string& name() const {
  return wff_;
}

friend std::ostream& operator <<(std::ostream &os, const Key2 &key);
};

struct Factor2 {
std::string wff_;
Factor2() :
wff_("@") {
}
Factor2(const std::string& s) :
wff_(s) {
}
Factor2(const Key2& key) :
wff_(key.name()) {
}

friend std::ostream& operator <<(std::ostream &os, const Factor2 &f);
friend Factor2 operator -(const Key2& key);
};

std::ostream& operator <<(std::ostream &os, const Factor2 &f) {
os << f.wff_;
return os;
}

Factor2 operator -(const Key2& key) {
return Factor2("-" + key.name());
}

Factor2 operator ||(const Factor2 &factor1, const Factor2 &factor2) {
return Factor2(std::string("(") + factor1.wff_ + " || " + factor2.wff_ + ")");
}

Factor2 operator &&(const Factor2 &factor1, const Factor2 &factor2) {
return Factor2(std::string("(") + factor1.wff_ + " && " + factor2.wff_ + ")");
}

Factor2 operator >>(const Factor2 &factor1, const Factor2 &factor2) {
return Factor2(std::string("(") + factor1.wff_ + " >> " + factor2.wff_ + ")");
}

struct Graph2: public std::list<Factor2> {

//  void operator +=(const Graph2& graph) {
//    for(const Factor2& f: graph)
//        push_back(f);
//  }
friend std::ostream& operator <<(std::ostream &os, const Graph2& graph);

};

//Graph2 operator +=(Graph2& graph, const Factor2& factor) {
//  graph.push_back(factor);
//  return graph;
//}
std::ostream& operator <<(std::ostream &os, const Graph2& graph) {
for(const Factor2& f: graph)
os << f << endl;
return os;
}

/* ************************************************************************* */
TEST(DiscreteFactorGraph, Sugar)
{
Key2 M("Mythical"), I("Immortal"), A("Mammal"), H("Horned"), G("Magical");

// Test this desired construction
Graph2 unicorns;
unicorns += M >> -A;
unicorns += (-M) >> (-I && A);
unicorns += (I || A) >> H;
unicorns += H >> G;

// should be done by adapting boost::assign:
// unicorns += (-M) >> (-I && A), (I || A) >> H , H >> G;

cout << unicorns;
}
#endif

/* ************************************************************************* */
int main() {
TestResult tr;
return TestRegistry::runAllTests(tr);
}
/* ************************************************************************* */