gtsam/gtsam/hybrid/tests/testHybridGaussianISAM.cpp

506 lines
19 KiB
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 testHybridGaussianISAM.cpp
* @brief Unit tests for incremental inference
* @author Fan Jiang, Varun Agrawal, Frank Dellaert
* @date Jan 2021
*/
#include <gtsam/discrete/DiscreteBayesNet.h>
#include <gtsam/discrete/DiscreteDistribution.h>
#include <gtsam/discrete/DiscreteFactorGraph.h>
#include <gtsam/geometry/Pose2.h>
#include <gtsam/hybrid/HybridConditional.h>
#include <gtsam/hybrid/HybridGaussianISAM.h>
#include <gtsam/linear/GaussianBayesNet.h>
#include <gtsam/linear/GaussianFactorGraph.h>
#include <gtsam/nonlinear/PriorFactor.h>
#include <gtsam/sam/BearingRangeFactor.h>
#include "Switching.h"
// Include for test suite
#include <CppUnitLite/TestHarness.h>
using namespace std;
using namespace gtsam;
using symbol_shorthand::M;
using symbol_shorthand::W;
using symbol_shorthand::X;
using symbol_shorthand::Y;
using symbol_shorthand::Z;
/* ****************************************************************************/
namespace switching3 {
// ϕ(x0) ϕ(x0,x1,m0) ϕ(x1,x2,m1) ϕ(x1;z1) ϕ(x2;z2) ϕ(m0) ϕ(m0,m1)
const Switching switching(3);
const HybridGaussianFactorGraph &lfg = switching.linearizedFactorGraph;
// First update graph: ϕ(x0) ϕ(x0,x1,m0) ϕ(m0)
const HybridGaussianFactorGraph graph1{lfg.at(0), lfg.at(1), lfg.at(5)};
// Second update graph: ϕ(x1,x2,m1) ϕ(x1;z1) ϕ(x2;z2) ϕ(m0,m1)
const HybridGaussianFactorGraph graph2{lfg.at(2), lfg.at(3), lfg.at(4),
lfg.at(6)};
} // namespace switching3
/* ****************************************************************************/
// Test if we can perform elimination incrementally.
TEST(HybridGaussianElimination, IncrementalElimination) {
using namespace switching3;
HybridGaussianISAM isam;
// Run first update step
isam.update(graph1);
// Check that after update we have 2 hybrid Bayes net nodes:
// P(M0) and P(X0, X1 | M0)
EXPECT_LONGS_EQUAL(2, isam.size());
EXPECT(isam[M(0)]->conditional()->frontals() == KeyVector({M(0)}));
EXPECT(isam[M(0)]->conditional()->parents() == KeyVector());
EXPECT(isam[X(0)]->conditional()->frontals() == KeyVector({X(0), X(1)}));
EXPECT(isam[X(0)]->conditional()->parents() == KeyVector({M(0)}));
/********************************************************/
// Run second update step
isam.update(graph2);
// Check that after update we have 3 hybrid Bayes net nodes:
// P(X1, X2 | M0, M1) P(X1, X2 | M0, M1)
EXPECT_LONGS_EQUAL(3, isam.size());
EXPECT(isam[M(0)]->conditional()->frontals() == KeyVector({M(0), M(1)}));
EXPECT(isam[M(0)]->conditional()->parents() == KeyVector());
EXPECT(isam[X(1)]->conditional()->frontals() == KeyVector({X(1), X(2)}));
EXPECT(isam[X(1)]->conditional()->parents() == KeyVector({M(0), M(1)}));
EXPECT(isam[X(0)]->conditional()->frontals() == KeyVector{X(0)});
EXPECT(isam[X(0)]->conditional()->parents() == KeyVector({X(1), M(0)}));
}
/* ****************************************************************************/
// Test if we can incrementally do the inference
TEST(HybridGaussianElimination, IncrementalInference) {
using namespace switching3;
HybridGaussianISAM isam;
// Run update step
isam.update(graph1);
auto discreteConditional_m0 = isam[M(0)]->conditional()->asDiscrete();
EXPECT(discreteConditional_m0->keys() == KeyVector({M(0)}));
/********************************************************/
// Second incremental update.
isam.update(graph2);
/********************************************************/
// Run batch elimination so we can compare results.
const Ordering ordering{X(0), X(1), X(2)};
// Now we calculate the expected factors using full elimination
const auto [expectedHybridBayesTree, expectedRemainingGraph] =
switching.linearizedFactorGraph.eliminatePartialMultifrontal(ordering);
// The densities on X(0) should be the same
auto x0_conditional = dynamic_pointer_cast<HybridGaussianConditional>(
isam[X(0)]->conditional()->inner());
auto expected_x0_conditional =
dynamic_pointer_cast<HybridGaussianConditional>(
(*expectedHybridBayesTree)[X(0)]->conditional()->inner());
EXPECT(assert_equal(*x0_conditional, *expected_x0_conditional));
// The densities on X(1) should be the same
auto x1_conditional = dynamic_pointer_cast<HybridGaussianConditional>(
isam[X(1)]->conditional()->inner());
auto expected_x1_conditional =
dynamic_pointer_cast<HybridGaussianConditional>(
(*expectedHybridBayesTree)[X(1)]->conditional()->inner());
EXPECT(assert_equal(*x1_conditional, *expected_x1_conditional));
// The densities on X(2) should be the same
auto x2_conditional = dynamic_pointer_cast<HybridGaussianConditional>(
isam[X(2)]->conditional()->inner());
auto expected_x2_conditional =
dynamic_pointer_cast<HybridGaussianConditional>(
(*expectedHybridBayesTree)[X(2)]->conditional()->inner());
EXPECT(assert_equal(*x2_conditional, *expected_x2_conditional));
// We only perform manual continuous elimination for 0,0.
// The other discrete probabilities on M(2) are calculated the same way
const Ordering discreteOrdering{M(0), M(1)};
HybridBayesTree::shared_ptr discreteBayesTree =
expectedRemainingGraph->eliminateMultifrontal(discreteOrdering);
// Test the probability values with regression tests.
auto discrete = isam[M(1)]->conditional()->asDiscrete();
EXPECT(assert_equal(0.095292, (*discrete)({{M(0), 0}, {M(1), 0}}), 1e-5));
EXPECT(assert_equal(0.282758, (*discrete)({{M(0), 1}, {M(1), 0}}), 1e-5));
EXPECT(assert_equal(0.314175, (*discrete)({{M(0), 0}, {M(1), 1}}), 1e-5));
EXPECT(assert_equal(0.307775, (*discrete)({{M(0), 1}, {M(1), 1}}), 1e-5));
// Check that the clique conditional generated from incremental elimination
// matches that of batch elimination.
auto expectedConditional = (*discreteBayesTree)[M(1)]->conditional();
auto actualConditional = isam[M(1)]->conditional();
EXPECT(assert_equal(*expectedConditional, *actualConditional, 1e-6));
}
/* ****************************************************************************/
// Test if we can approximately do the inference
TEST(HybridGaussianElimination, Approx_inference) {
Switching switching(4);
HybridGaussianISAM incrementalHybrid;
HybridGaussianFactorGraph graph1;
// Add the 3 hybrid factors, x0-x1, x1-x2, x2-x3
for (size_t i = 1; i < 4; i++) {
graph1.push_back(switching.linearizedFactorGraph.at(i));
}
// Add the Gaussian factors, 1 prior on X(0),
// 3 measurements on X(1), X(2), X(3)
graph1.push_back(switching.linearizedFactorGraph.at(0));
for (size_t i = 4; i <= 7; i++) {
graph1.push_back(switching.linearizedFactorGraph.at(i));
}
// Create ordering.
Ordering ordering;
for (size_t j = 0; j < 4; j++) {
ordering.push_back(X(j));
}
// Now we calculate the actual factors using full elimination
const auto [unPrunedHybridBayesTree, unPrunedRemainingGraph] =
switching.linearizedFactorGraph.eliminatePartialMultifrontal(ordering);
size_t maxNrLeaves = 5;
incrementalHybrid.update(graph1);
incrementalHybrid.prune(maxNrLeaves);
/*
unPruned factor is:
Choice(m3)
0 Choice(m2)
0 0 Choice(m1)
0 0 0 Leaf 0.11267528
0 0 1 Leaf 0.18576102
0 1 Choice(m1)
0 1 0 Leaf 0.18754662
0 1 1 Leaf 0.30623871
1 Choice(m2)
1 0 Choice(m1)
1 0 0 Leaf 0.18576102
1 0 1 Leaf 0.30622428
1 1 Choice(m1)
1 1 0 Leaf 0.30623871
1 1 1 Leaf 0.5
pruned factors is:
Choice(m3)
0 Choice(m2)
0 0 Leaf 0
0 1 Choice(m1)
0 1 0 Leaf 0.18754662
0 1 1 Leaf 0.30623871
1 Choice(m2)
1 0 Choice(m1)
1 0 0 Leaf 0
1 0 1 Leaf 0.30622428
1 1 Choice(m1)
1 1 0 Leaf 0.30623871
1 1 1 Leaf 0.5
*/
auto discreteConditional_m0 = *dynamic_pointer_cast<DiscreteConditional>(
incrementalHybrid[M(0)]->conditional()->inner());
EXPECT(discreteConditional_m0.keys() == KeyVector({M(0), M(1), M(2)}));
// Get the number of elements which are greater than 0.
auto count = [](const double &value, int count) {
return value > 0 ? count + 1 : count;
};
// Check that the number of leaves after pruning is 5.
EXPECT_LONGS_EQUAL(5, discreteConditional_m0.fold(count, 0));
// Check that the hybrid nodes of the bayes net match those of the pre-pruning
// bayes net, at the same positions.
auto &unPrunedLastDensity = *dynamic_pointer_cast<HybridGaussianConditional>(
unPrunedHybridBayesTree->clique(X(3))->conditional()->inner());
auto &lastDensity = *dynamic_pointer_cast<HybridGaussianConditional>(
incrementalHybrid[X(3)]->conditional()->inner());
std::vector<std::pair<DiscreteValues, double>> assignments =
discreteConditional_m0.enumerate();
// Loop over all assignments and check the pruned components
for (auto &&av : assignments) {
const DiscreteValues &assignment = av.first;
const double value = av.second;
if (value == 0.0) {
EXPECT(lastDensity(assignment) == nullptr);
} else {
CHECK(lastDensity(assignment));
EXPECT(assert_equal(*unPrunedLastDensity(assignment),
*lastDensity(assignment)));
}
}
}
/* ****************************************************************************/
// Test approximate inference with an additional pruning step.
TEST(HybridGaussianElimination, IncrementalApproximate) {
Switching switching(5);
HybridGaussianISAM incrementalHybrid;
HybridGaussianFactorGraph graph1;
/***** Run Round 1 *****/
// Add the 3 hybrid factors, x0-x1, x1-x2, x2-x3
for (size_t i = 1; i < 4; i++) {
graph1.push_back(switching.linearizedFactorGraph.at(i));
}
// Add the Gaussian factors, 1 prior on X(0),
// 3 measurements on X(1), X(2), X(3)
graph1.push_back(switching.linearizedFactorGraph.at(0));
for (size_t i = 5; i <= 7; i++) {
graph1.push_back(switching.linearizedFactorGraph.at(i));
}
// Run update with pruning
size_t maxComponents = 5;
incrementalHybrid.update(graph1);
incrementalHybrid.prune(maxComponents);
// Check if we have a bayes tree with 4 hybrid nodes,
// each with 2, 4, 8, and 5 (pruned) leaves respectively.
EXPECT_LONGS_EQUAL(4, incrementalHybrid.size());
EXPECT_LONGS_EQUAL(
2, incrementalHybrid[X(0)]->conditional()->asHybrid()->nrComponents());
EXPECT_LONGS_EQUAL(
3, incrementalHybrid[X(1)]->conditional()->asHybrid()->nrComponents());
EXPECT_LONGS_EQUAL(
5, incrementalHybrid[X(2)]->conditional()->asHybrid()->nrComponents());
EXPECT_LONGS_EQUAL(
5, incrementalHybrid[X(3)]->conditional()->asHybrid()->nrComponents());
/***** Run Round 2 *****/
HybridGaussianFactorGraph graph2;
graph2.push_back(switching.linearizedFactorGraph.at(4));
graph2.push_back(switching.linearizedFactorGraph.at(8));
// Run update with pruning a second time.
incrementalHybrid.update(graph2);
incrementalHybrid.prune(maxComponents);
// Check if we have a bayes tree with pruned hybrid nodes,
// with 5 (pruned) leaves.
CHECK_EQUAL(5, incrementalHybrid.size());
EXPECT_LONGS_EQUAL(
5, incrementalHybrid[X(3)]->conditional()->asHybrid()->nrComponents());
EXPECT_LONGS_EQUAL(
5, incrementalHybrid[X(4)]->conditional()->asHybrid()->nrComponents());
}
/* ************************************************************************/
// A GTSAM-only test for running inference on a single-legged robot.
// The leg links are represented by the chain X-Y-Z-W, where X is the base and
// W is the foot.
// We use BetweenFactor<Pose2> as constraints between each of the poses.
TEST(HybridGaussianISAM, NonTrivial) {
/*************** Run Round 1 ***************/
HybridNonlinearFactorGraph fg;
// Add a prior on pose x0 at the origin.
// A prior factor consists of a mean and
// a noise model (covariance matrix)
Pose2 prior(0.0, 0.0, 0.0); // prior mean is at origin
auto priorNoise = noiseModel::Diagonal::Sigmas(
Vector3(0.3, 0.3, 0.1)); // 30cm std on x,y, 0.1 rad on theta
fg.emplace_shared<PriorFactor<Pose2>>(X(0), prior, priorNoise);
// create a noise model for the landmark measurements
auto poseNoise = noiseModel::Isotropic::Sigma(3, 0.1);
// We model a robot's single leg as X - Y - Z - W
// where X is the base link and W is the foot link.
// Add connecting poses similar to PoseFactors in GTD
fg.emplace_shared<BetweenFactor<Pose2>>(X(0), Y(0), Pose2(0, 1.0, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Y(0), Z(0), Pose2(0, 1.0, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Z(0), W(0), Pose2(0, 1.0, 0),
poseNoise);
// Create initial estimate
Values initial;
initial.insert(X(0), Pose2(0.0, 0.0, 0.0));
initial.insert(Y(0), Pose2(0.0, 1.0, 0.0));
initial.insert(Z(0), Pose2(0.0, 2.0, 0.0));
initial.insert(W(0), Pose2(0.0, 3.0, 0.0));
HybridGaussianFactorGraph gfg = *fg.linearize(initial);
fg = HybridNonlinearFactorGraph();
HybridGaussianISAM inc;
// Update without pruning
// The result is a HybridBayesNet with no discrete variables
// (equivalent to a GaussianBayesNet).
// Factorization is:
// `P(X | measurements) = P(W0|Z0) P(Z0|Y0) P(Y0|X0) P(X0)`
inc.update(gfg);
/*************** Run Round 2 ***************/
using PlanarMotionModel = BetweenFactor<Pose2>;
// Add odometry factor with discrete modes.
Pose2 odometry(1.0, 0.0, 0.0);
auto noise_model = noiseModel::Isotropic::Sigma(3, 1.0);
std::vector<NoiseModelFactor::shared_ptr> components;
components.emplace_back(
new PlanarMotionModel(W(0), W(1), odometry, noise_model)); // moving
components.emplace_back(
new PlanarMotionModel(W(0), W(1), Pose2(0, 0, 0), noise_model)); // still
fg.emplace_shared<HybridNonlinearFactor>(DiscreteKey(M(1), 2), components);
// Add equivalent of ImuFactor
fg.emplace_shared<BetweenFactor<Pose2>>(X(0), X(1), Pose2(1.0, 0.0, 0),
poseNoise);
// PoseFactors-like at k=1
fg.emplace_shared<BetweenFactor<Pose2>>(X(1), Y(1), Pose2(0, 1, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Y(1), Z(1), Pose2(0, 1, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Z(1), W(1), Pose2(-1, 1, 0),
poseNoise);
initial.insert(X(1), Pose2(1.0, 0.0, 0.0));
initial.insert(Y(1), Pose2(1.0, 1.0, 0.0));
initial.insert(Z(1), Pose2(1.0, 2.0, 0.0));
// The leg link did not move so we set the expected pose accordingly.
initial.insert(W(1), Pose2(0.0, 3.0, 0.0));
gfg = *fg.linearize(initial);
fg = HybridNonlinearFactorGraph();
// Update without pruning
// The result is a HybridBayesNet with 1 discrete variable M(1).
// P(X | measurements) = P(W0|Z0, W1, M1) P(Z0|Y0, W1, M1) P(Y0|X0, W1, M1)
// P(X0 | X1, W1, M1) P(W1|Z1, X1, M1) P(Z1|Y1, X1, M1)
// P(Y1 | X1, M1)P(X1 | M1)P(M1)
// The MHS tree is a 1 level tree for time indices (1,) with 2 leaves.
inc.update(gfg);
/*************** Run Round 3 ***************/
// Add odometry factor with discrete modes.
components.clear();
components.emplace_back(
new PlanarMotionModel(W(1), W(2), odometry, noise_model)); // moving
components.emplace_back(
new PlanarMotionModel(W(1), W(2), Pose2(0, 0, 0), noise_model)); // still
fg.emplace_shared<HybridNonlinearFactor>(DiscreteKey(M(2), 2), components);
// Add equivalent of ImuFactor
fg.emplace_shared<BetweenFactor<Pose2>>(X(1), X(2), Pose2(1.0, 0.0, 0),
poseNoise);
// PoseFactors-like at k=1
fg.emplace_shared<BetweenFactor<Pose2>>(X(2), Y(2), Pose2(0, 1, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Y(2), Z(2), Pose2(0, 1, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Z(2), W(2), Pose2(-2, 1, 0),
poseNoise);
initial.insert(X(2), Pose2(2.0, 0.0, 0.0));
initial.insert(Y(2), Pose2(2.0, 1.0, 0.0));
initial.insert(Z(2), Pose2(2.0, 2.0, 0.0));
initial.insert(W(2), Pose2(0.0, 3.0, 0.0));
gfg = *fg.linearize(initial);
fg = HybridNonlinearFactorGraph();
// Now we prune!
// P(X | measurements) = P(W0|Z0, W1, M1) P(Z0|Y0, W1, M1) P(Y0|X0, W1, M1)
// P(X0 | X1, W1, M1) P(W1|W2, Z1, X1, M1, M2)
// P(Z1| W2, Y1, X1, M1, M2) P(Y1 | W2, X1, M1, M2)
// P(X1 | W2, X2, M1, M2) P(W2|Z2, X2, M1, M2)
// P(Z2|Y2, X2, M1, M2) P(Y2 | X2, M1, M2)
// P(X2 | M1, M2) P(M1, M2)
// The MHS at this point should be a 2 level tree on (1, 2).
// 1 has 2 choices, and 2 has 4 choices.
inc.update(gfg);
inc.prune(2);
/*************** Run Round 4 ***************/
// Add odometry factor with discrete modes.
components.clear();
components.emplace_back(
new PlanarMotionModel(W(2), W(3), odometry, noise_model)); // moving
components.emplace_back(
new PlanarMotionModel(W(2), W(3), Pose2(0, 0, 0), noise_model)); // still
fg.emplace_shared<HybridNonlinearFactor>(DiscreteKey(M(3), 2), components);
// Add equivalent of ImuFactor
fg.emplace_shared<BetweenFactor<Pose2>>(X(2), X(3), Pose2(1.0, 0.0, 0),
poseNoise);
// PoseFactors-like at k=3
fg.emplace_shared<BetweenFactor<Pose2>>(X(3), Y(3), Pose2(0, 1, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Y(3), Z(3), Pose2(0, 1, 0),
poseNoise);
fg.emplace_shared<BetweenFactor<Pose2>>(Z(3), W(3), Pose2(-3, 1, 0),
poseNoise);
initial.insert(X(3), Pose2(3.0, 0.0, 0.0));
initial.insert(Y(3), Pose2(3.0, 1.0, 0.0));
initial.insert(Z(3), Pose2(3.0, 2.0, 0.0));
initial.insert(W(3), Pose2(0.0, 3.0, 0.0));
gfg = *fg.linearize(initial);
fg = HybridNonlinearFactorGraph();
// Keep pruning!
inc.update(gfg);
inc.prune(3);
// The final discrete graph should not be empty since we have eliminated
// all continuous variables.
auto discreteTree = inc[M(3)]->conditional()->asDiscrete();
EXPECT_LONGS_EQUAL(3, discreteTree->size());
// Test if the optimal discrete mode assignment is (1, 1, 1).
DiscreteFactorGraph discreteGraph;
discreteGraph.push_back(discreteTree);
DiscreteValues optimal_assignment = discreteGraph.optimize();
DiscreteValues expected_assignment;
expected_assignment[M(1)] = 1;
expected_assignment[M(2)] = 1;
expected_assignment[M(3)] = 1;
EXPECT(assert_equal(expected_assignment, optimal_assignment));
// Test if pruning worked correctly by checking that we only have 3 leaves in
// the last node.
auto lastConditional = inc[X(3)]->conditional()->asHybrid();
EXPECT_LONGS_EQUAL(3, lastConditional->nrComponents());
}
/* ************************************************************************* */
int main() {
TestResult tr;
return TestRegistry::runAllTests(tr);
}