gtsam/gtsam/hybrid/tests/testHybridBayesNet.cpp

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C++

/* ----------------------------------------------------------------------------
* 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 testHybridBayesNet.cpp
* @brief Unit tests for HybridBayesNet
* @author Varun Agrawal
* @author Fan Jiang
* @author Frank Dellaert
* @date December 2021
*/
#include <gtsam/base/serializationTestHelpers.h>
#include <gtsam/hybrid/HybridBayesNet.h>
#include <gtsam/hybrid/HybridBayesTree.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include "TinyHybridExample.h"
#include "Switching.h"
// Include for test suite
#include <CppUnitLite/TestHarness.h>
using namespace std;
using namespace gtsam;
using namespace gtsam::serializationTestHelpers;
using noiseModel::Isotropic;
using symbol_shorthand::M;
using symbol_shorthand::X;
static const Key asiaKey = 0;
static const DiscreteKey Asia(asiaKey, 2);
/* ****************************************************************************/
// Test creation of a pure discrete Bayes net.
TEST(HybridBayesNet, Creation) {
HybridBayesNet bayesNet;
bayesNet.emplaceDiscrete(Asia, "99/1");
DiscreteConditional expected(Asia, "99/1");
CHECK(bayesNet.atDiscrete(0));
EXPECT(assert_equal(expected, *bayesNet.atDiscrete(0)));
}
/* ****************************************************************************/
// Test adding a Bayes net to another one.
TEST(HybridBayesNet, Add) {
HybridBayesNet bayesNet;
bayesNet.emplaceDiscrete(Asia, "99/1");
HybridBayesNet other;
other.push_back(bayesNet);
EXPECT(bayesNet.equals(other));
}
/* ****************************************************************************/
// Test evaluate for a pure discrete Bayes net P(Asia).
TEST(HybridBayesNet, EvaluatePureDiscrete) {
HybridBayesNet bayesNet;
bayesNet.emplaceDiscrete(Asia, "99/1");
HybridValues values;
values.insert(asiaKey, 0);
EXPECT_DOUBLES_EQUAL(0.99, bayesNet.evaluate(values), 1e-9);
}
/* ****************************************************************************/
// Test creation of a tiny hybrid Bayes net.
TEST(HybridBayesNet, Tiny) {
auto bayesNet = tiny::createHybridBayesNet();
EXPECT_LONGS_EQUAL(3, bayesNet.size());
}
/* ****************************************************************************/
// Test evaluate for a hybrid Bayes net P(X0|X1) P(X1|Asia) P(Asia).
TEST(HybridBayesNet, evaluateHybrid) {
const auto continuousConditional = GaussianConditional::FromMeanAndStddev(
X(0), 2 * I_1x1, X(1), Vector1(-4.0), 5.0);
const SharedDiagonal model0 = noiseModel::Diagonal::Sigmas(Vector1(2.0)),
model1 = noiseModel::Diagonal::Sigmas(Vector1(3.0));
const auto conditional0 = boost::make_shared<GaussianConditional>(
X(1), Vector1::Constant(5), I_1x1, model0),
conditional1 = boost::make_shared<GaussianConditional>(
X(1), Vector1::Constant(2), I_1x1, model1);
// Create hybrid Bayes net.
HybridBayesNet bayesNet;
bayesNet.emplaceGaussian(continuousConditional);
GaussianMixture gm({X(1)}, {}, {Asia}, {conditional0, conditional1});
bayesNet.emplaceMixture(gm); // copy :-(
bayesNet.emplaceDiscrete(Asia, "99/1");
// Create values at which to evaluate.
HybridValues values;
values.insert(asiaKey, 0);
values.insert(X(0), Vector1(-6));
values.insert(X(1), Vector1(1));
const double conditionalProbability =
continuousConditional.evaluate(values.continuous());
const double mixtureProbability = conditional0->evaluate(values.continuous());
EXPECT_DOUBLES_EQUAL(conditionalProbability * mixtureProbability * 0.99,
bayesNet.evaluate(values), 1e-9);
}
/* ****************************************************************************/
// Test choosing an assignment of conditionals
TEST(HybridBayesNet, Choose) {
Switching s(4);
Ordering ordering;
for (auto&& kvp : s.linearizationPoint) {
ordering += kvp.key;
}
HybridBayesNet::shared_ptr hybridBayesNet;
HybridGaussianFactorGraph::shared_ptr remainingFactorGraph;
std::tie(hybridBayesNet, remainingFactorGraph) =
s.linearizedFactorGraph.eliminatePartialSequential(ordering);
DiscreteValues assignment;
assignment[M(0)] = 1;
assignment[M(1)] = 1;
assignment[M(2)] = 0;
GaussianBayesNet gbn = hybridBayesNet->choose(assignment);
EXPECT_LONGS_EQUAL(4, gbn.size());
EXPECT(assert_equal(*(*boost::dynamic_pointer_cast<GaussianMixture>(
hybridBayesNet->atMixture(0)))(assignment),
*gbn.at(0)));
EXPECT(assert_equal(*(*boost::dynamic_pointer_cast<GaussianMixture>(
hybridBayesNet->atMixture(1)))(assignment),
*gbn.at(1)));
EXPECT(assert_equal(*(*boost::dynamic_pointer_cast<GaussianMixture>(
hybridBayesNet->atMixture(2)))(assignment),
*gbn.at(2)));
EXPECT(assert_equal(*(*boost::dynamic_pointer_cast<GaussianMixture>(
hybridBayesNet->atMixture(3)))(assignment),
*gbn.at(3)));
}
/* ****************************************************************************/
// Test Bayes net optimize
TEST(HybridBayesNet, OptimizeAssignment) {
Switching s(4);
Ordering ordering;
for (auto&& kvp : s.linearizationPoint) {
ordering += kvp.key;
}
HybridBayesNet::shared_ptr hybridBayesNet;
HybridGaussianFactorGraph::shared_ptr remainingFactorGraph;
std::tie(hybridBayesNet, remainingFactorGraph) =
s.linearizedFactorGraph.eliminatePartialSequential(ordering);
DiscreteValues assignment;
assignment[M(0)] = 1;
assignment[M(1)] = 1;
assignment[M(2)] = 1;
VectorValues delta = hybridBayesNet->optimize(assignment);
// The linearization point has the same value as the key index,
// e.g. X(0) = 1, X(1) = 2,
// but the factors specify X(k) = k-1, so delta should be -1.
VectorValues expected_delta;
expected_delta.insert(make_pair(X(0), -Vector1::Ones()));
expected_delta.insert(make_pair(X(1), -Vector1::Ones()));
expected_delta.insert(make_pair(X(2), -Vector1::Ones()));
expected_delta.insert(make_pair(X(3), -Vector1::Ones()));
EXPECT(assert_equal(expected_delta, delta));
}
/* ****************************************************************************/
// Test Bayes net optimize
TEST(HybridBayesNet, Optimize) {
Switching s(4, 1.0, 0.1, {0, 1, 2, 3}, "1/1 1/1");
Ordering hybridOrdering = s.linearizedFactorGraph.getHybridOrdering();
HybridBayesNet::shared_ptr hybridBayesNet =
s.linearizedFactorGraph.eliminateSequential(hybridOrdering);
HybridValues delta = hybridBayesNet->optimize();
// NOTE: The true assignment is 111, but the discrete priors cause 101
DiscreteValues expectedAssignment;
expectedAssignment[M(0)] = 1;
expectedAssignment[M(1)] = 1;
expectedAssignment[M(2)] = 1;
EXPECT(assert_equal(expectedAssignment, delta.discrete()));
VectorValues expectedValues;
expectedValues.insert(X(0), -Vector1::Ones());
expectedValues.insert(X(1), -Vector1::Ones());
expectedValues.insert(X(2), -Vector1::Ones());
expectedValues.insert(X(3), -Vector1::Ones());
EXPECT(assert_equal(expectedValues, delta.continuous(), 1e-5));
}
/* ****************************************************************************/
// Test Bayes net error
TEST(HybridBayesNet, Error) {
Switching s(3);
Ordering hybridOrdering = s.linearizedFactorGraph.getHybridOrdering();
HybridBayesNet::shared_ptr hybridBayesNet =
s.linearizedFactorGraph.eliminateSequential(hybridOrdering);
HybridValues delta = hybridBayesNet->optimize();
auto error_tree = hybridBayesNet->error(delta.continuous());
std::vector<DiscreteKey> discrete_keys = {{M(0), 2}, {M(1), 2}};
std::vector<double> leaves = {0.0097568009, 3.3973404e-31, 0.029126214,
0.0097568009};
AlgebraicDecisionTree<Key> expected_error(discrete_keys, leaves);
// regression
EXPECT(assert_equal(expected_error, error_tree, 1e-9));
// Error on pruned Bayes net
auto prunedBayesNet = hybridBayesNet->prune(2);
auto pruned_error_tree = prunedBayesNet.error(delta.continuous());
std::vector<double> pruned_leaves = {2e50, 3.3973404e-31, 2e50, 0.0097568009};
AlgebraicDecisionTree<Key> expected_pruned_error(discrete_keys,
pruned_leaves);
// regression
EXPECT(assert_equal(expected_pruned_error, pruned_error_tree, 1e-9));
// Verify error computation and check for specific error value
DiscreteValues discrete_values {{M(0), 1}, {M(1), 1}};
double total_error = 0;
for (size_t idx = 0; idx < hybridBayesNet->size(); idx++) {
if (hybridBayesNet->at(idx)->isHybrid()) {
double error = hybridBayesNet->atMixture(idx)->error(
{delta.continuous(), discrete_values});
total_error += error;
} else if (hybridBayesNet->at(idx)->isContinuous()) {
double error = hybridBayesNet->atGaussian(idx)->error(delta.continuous());
total_error += error;
}
}
EXPECT_DOUBLES_EQUAL(
total_error, hybridBayesNet->error({delta.continuous(), discrete_values}),
1e-9);
EXPECT_DOUBLES_EQUAL(total_error, error_tree(discrete_values), 1e-9);
EXPECT_DOUBLES_EQUAL(total_error, pruned_error_tree(discrete_values), 1e-9);
}
/* ****************************************************************************/
// Test Bayes net pruning
TEST(HybridBayesNet, Prune) {
Switching s(4);
Ordering hybridOrdering = s.linearizedFactorGraph.getHybridOrdering();
HybridBayesNet::shared_ptr hybridBayesNet =
s.linearizedFactorGraph.eliminateSequential(hybridOrdering);
HybridValues delta = hybridBayesNet->optimize();
auto prunedBayesNet = hybridBayesNet->prune(2);
HybridValues pruned_delta = prunedBayesNet.optimize();
EXPECT(assert_equal(delta.discrete(), pruned_delta.discrete()));
EXPECT(assert_equal(delta.continuous(), pruned_delta.continuous()));
}
/* ****************************************************************************/
// Test Bayes net updateDiscreteConditionals
TEST(HybridBayesNet, UpdateDiscreteConditionals) {
Switching s(4);
Ordering hybridOrdering = s.linearizedFactorGraph.getHybridOrdering();
HybridBayesNet::shared_ptr hybridBayesNet =
s.linearizedFactorGraph.eliminateSequential(hybridOrdering);
size_t maxNrLeaves = 3;
auto discreteConditionals = hybridBayesNet->discreteConditionals();
const DecisionTreeFactor::shared_ptr prunedDecisionTree =
boost::make_shared<DecisionTreeFactor>(
discreteConditionals->prune(maxNrLeaves));
EXPECT_LONGS_EQUAL(maxNrLeaves + 2 /*2 zero leaves*/,
prunedDecisionTree->nrLeaves());
auto original_discrete_conditionals = *(hybridBayesNet->at(4)->asDiscrete());
// Prune!
hybridBayesNet->prune(maxNrLeaves);
// Functor to verify values against the original_discrete_conditionals
auto checker = [&](const Assignment<Key>& assignment,
double probability) -> double {
// typecast so we can use this to get probability value
DiscreteValues choices(assignment);
if (prunedDecisionTree->operator()(choices) == 0) {
EXPECT_DOUBLES_EQUAL(0.0, probability, 1e-9);
} else {
EXPECT_DOUBLES_EQUAL(original_discrete_conditionals(choices), probability,
1e-9);
}
return 0.0;
};
// Get the pruned discrete conditionals as an AlgebraicDecisionTree
auto pruned_discrete_conditionals = hybridBayesNet->at(4)->asDiscrete();
auto discrete_conditional_tree =
boost::dynamic_pointer_cast<DecisionTreeFactor::ADT>(
pruned_discrete_conditionals);
// The checker functor verifies the values for us.
discrete_conditional_tree->apply(checker);
}
/* ****************************************************************************/
// Test HybridBayesNet serialization.
TEST(HybridBayesNet, Serialization) {
Switching s(4);
Ordering ordering = s.linearizedFactorGraph.getHybridOrdering();
HybridBayesNet hbn = *(s.linearizedFactorGraph.eliminateSequential(ordering));
EXPECT(equalsObj<HybridBayesNet>(hbn));
EXPECT(equalsXML<HybridBayesNet>(hbn));
EXPECT(equalsBinary<HybridBayesNet>(hbn));
}
/* ****************************************************************************/
// Test HybridBayesNet sampling.
TEST(HybridBayesNet, Sampling) {
HybridNonlinearFactorGraph nfg;
auto noise_model = noiseModel::Diagonal::Sigmas(Vector1(1.0));
auto zero_motion =
boost::make_shared<BetweenFactor<double>>(X(0), X(1), 0, noise_model);
auto one_motion =
boost::make_shared<BetweenFactor<double>>(X(0), X(1), 1, noise_model);
std::vector<NonlinearFactor::shared_ptr> factors = {zero_motion, one_motion};
nfg.emplace_nonlinear<PriorFactor<double>>(X(0), 0.0, noise_model);
nfg.emplace_hybrid<MixtureFactor>(
KeyVector{X(0), X(1)}, DiscreteKeys{DiscreteKey(M(0), 2)}, factors);
DiscreteKey mode(M(0), 2);
auto discrete_prior = boost::make_shared<DiscreteDistribution>(mode, "1/1");
nfg.push_discrete(discrete_prior);
Values initial;
double z0 = 0.0, z1 = 1.0;
initial.insert<double>(X(0), z0);
initial.insert<double>(X(1), z1);
// Create the factor graph from the nonlinear factor graph.
HybridGaussianFactorGraph::shared_ptr fg = nfg.linearize(initial);
// Eliminate into BN
Ordering ordering = fg->getHybridOrdering();
HybridBayesNet::shared_ptr bn = fg->eliminateSequential(ordering);
// Set up sampling
std::mt19937_64 gen(11);
// Initialize containers for computing the mean values.
vector<double> discrete_samples;
VectorValues average_continuous;
size_t num_samples = 1000;
for (size_t i = 0; i < num_samples; i++) {
// Sample
HybridValues sample = bn->sample(&gen);
discrete_samples.push_back(sample.discrete().at(M(0)));
if (i == 0) {
average_continuous.insert(sample.continuous());
} else {
average_continuous += sample.continuous();
}
}
EXPECT_LONGS_EQUAL(2, average_continuous.size());
EXPECT_LONGS_EQUAL(num_samples, discrete_samples.size());
// Regressions don't work across platforms :-(
// // regression for specific RNG seed
// double discrete_sum =
// std::accumulate(discrete_samples.begin(), discrete_samples.end(),
// decltype(discrete_samples)::value_type(0));
// EXPECT_DOUBLES_EQUAL(0.477, discrete_sum / num_samples, 1e-9);
// VectorValues expected;
// expected.insert({X(0), Vector1(-0.0131207162712)});
// expected.insert({X(1), Vector1(-0.499026377568)});
// // regression for specific RNG seed
// EXPECT(assert_equal(expected, average_continuous.scale(1.0 /
// num_samples)));
}
/* ************************************************************************* */
int main() {
TestResult tr;
return TestRegistry::runAllTests(tr);
}
/* ************************************************************************* */