Exemplo n.º 1
0
  public void testMdlToGraph() {
    List models = TestInference.createTestModels();
    for (Iterator mdlIt = models.iterator(); mdlIt.hasNext(); ) {
      UndirectedModel mdl = (UndirectedModel) mdlIt.next();
      UndirectedGraph g = Graphs.mdlToGraph(mdl);
      Set vertices = g.vertexSet();

      // check the number of vertices
      assertEquals(mdl.numVariables(), vertices.size());

      // check the number of edges
      int numEdgePtls = 0;
      for (Iterator factorIt = mdl.factors().iterator(); factorIt.hasNext(); ) {
        Factor factor = (Factor) factorIt.next();
        if (factor.varSet().size() == 2) numEdgePtls++;
      }
      assertEquals(numEdgePtls, g.edgeSet().size());

      // check that the neighbors of each vertex contain at least some of what they're supposed to
      Iterator it = vertices.iterator();
      while (it.hasNext()) {
        Variable var = (Variable) it.next();
        assertTrue(vertices.contains(var));
        Set neighborsInG = new HashSet(GraphHelper.neighborListOf(g, var));
        neighborsInG.add(var);

        Iterator factorIt = mdl.allFactorsContaining(var).iterator();
        while (factorIt.hasNext()) {
          Factor factor = (Factor) factorIt.next();
          assertTrue(neighborsInG.containsAll(factor.varSet()));
        }
      }
    }
  }
Exemplo n.º 2
0
  /**
   * Tests that models can be created that have multiple factors over the same edge, and that
   * potentialOfEdge returns the product in that case.
   */
  public void testMultipleEdgePotentials() {
    Variable v1 = new Variable(2);
    Variable v2 = new Variable(2);
    Variable[] vars = new Variable[] {v1, v2};

    FactorGraph mdl = new FactorGraph(vars);

    Factor ptl1 = new TableFactor(vars, new double[] {0.5, 0.5, 0.5, 0.5});
    mdl.addFactor(ptl1);

    Factor ptl2 = new TableFactor(vars, new double[] {0.25, 0.25, 0.5, 0.5});
    mdl.addFactor(ptl2);

    try {
      mdl.factorOf(v1, v2);
      fail();
    } catch (RuntimeException e) {
    }

    Collection factors = mdl.allFactorsContaining(new HashVarSet(vars));
    assertEquals(2, factors.size());
    assertTrue(factors.contains(ptl1));
    assertTrue(factors.contains(ptl2));

    double[] vals = {0.125, 0.125, 0.25, 0.25};
    Factor total = TableFactor.multiplyAll(factors);
    Factor expected = new TableFactor(vars, vals);

    assertTrue(
        "Arrays not equal\n  Expected "
            + ArrayUtils.toString(vals)
            + "\n  Actual "
            + ArrayUtils.toString(((TableFactor) total).toValueArray()),
        expected.almostEquals(total, 1e-10));
  }
Exemplo n.º 3
0
  private void verifyCachesConsistent(FactorGraph mdl) {
    Factor pot, pot2, pot3;
    for (Iterator it = mdl.factors().iterator(); it.hasNext(); ) {
      pot = (Factor) it.next();
      //				System.out.println("Testing model "+i+" potential "+pot);

      Object[] vars = pot.varSet().toArray();
      switch (vars.length) {
        case 1:
          pot2 = mdl.factorOf((Variable) vars[0]);
          assertTrue(pot == pot2);
          break;

        case 2:
          Variable var1 = (Variable) vars[0];
          Variable var2 = (Variable) vars[1];
          pot2 = mdl.factorOf(var1, var2);
          pot3 = mdl.factorOf(var2, var1);
          assertTrue(pot == pot2);
          assertTrue(pot2 == pot3);
          break;

          // Factors of size > 2 aren't now cached.
        default:
          break;
      }
    }
  }
Exemplo n.º 4
0
 private double sumValues(List ptlList, Assignment assn) {
   double sum = 0;
   for (Iterator it = ptlList.iterator(); it.hasNext(); ) {
     Factor ptl = (Factor) it.next();
     sum += ptl.logValue(assn);
   }
   return sum;
 }
Exemplo n.º 5
0
  public void testFactorOfSet() {
    Variable[] vars = new Variable[3];
    for (int i = 0; i < vars.length; i++) {
      vars[i] = new Variable(2);
    }
    Factor factor = new TableFactor(vars, new double[] {0, 1, 2, 3, 4, 5, 6, 7});

    FactorGraph fg = new FactorGraph(vars);
    fg.addFactor(factor);

    assertTrue(factor == fg.factorOf(factor.varSet()));

    HashSet set = new HashSet(factor.varSet());
    assertTrue(factor == fg.factorOf(set));
    set.remove(vars[0]);
    assertTrue(null == fg.factorOf(set));
  }
Exemplo n.º 6
0
  // backtracking search for a feasible assignment
  private Assignment initialAssignmentRec(FactorGraph mdl, Assignment assn, int fi) {
    if (fi >= mdl.factors().size()) return assn;
    Factor f = mdl.getFactor(fi);

    Factor sliced = f.slice(assn);
    if (sliced.varSet().isEmpty()) {
      double val = f.value(assn);
      if (val > 1e-50) {
        return initialAssignmentRec(mdl, assn, fi + 1);
      } else {
        return null;
      }
    }

    for (AssignmentIterator it = sliced.assignmentIterator(); it.hasNext(); ) {
      double val = sliced.value(it);
      if (val > 1e-50) {
        Assignment new_assn = Assignment.union(assn, it.assignment());
        Assignment assn_ret = initialAssignmentRec(mdl, new_assn, fi + 1);
        if (assn_ret != null) return assn_ret;
      }
      it.advance();
    }

    return null;
  }
  private void initJtCpts(FactorGraph mdl, JunctionTree jt) {
    for (Iterator it = jt.getVerticesIterator(); it.hasNext(); ) {
      VarSet c = (VarSet) it.next();
      //      DiscreteFactor ptl = createBlankFactor (c);
      //      jt.setCPF(c, ptl);
      jt.setCPF(c, new ConstantFactor(1.0));
    }

    for (Iterator it = mdl.factors().iterator(); it.hasNext(); ) {
      Factor ptl = (Factor) it.next();
      VarSet parent = jt.findParentCluster(ptl.varSet());
      assert parent != null : "Unable to find parent cluster for ptl " + ptl + "in jt " + jt;

      Factor cpf = jt.getCPF(parent);
      Factor newCpf = cpf.multiply(ptl);
      jt.setCPF(parent, newCpf);

      /* debug
      if (jt.isNaN()) {
        throw new RuntimeException ("Got a NaN");
      }
      */
    }
  }