gtsam/gtsam_unstable/nonlinear/tests/testSQPSimple.cpp

389 lines
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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 testQPSimple.cpp
* @brief Unit tests for testQPSimple
* @author Krunal Chande
* @author Duy-Nguyen Ta
* @author Luca Carlone
* @date Dec 15, 2014
*/
#include <gtsam/inference/Symbol.h>
#include <gtsam/nonlinear/NonlinearFactorGraph.h>
#include <gtsam/nonlinear/LinearContainerFactor.h>
#include <gtsam_unstable/linear/QPSolver.h>
#include <gtsam_unstable/nonlinear/NonlinearConstraint.h>
#include <CppUnitLite/TestHarness.h>
#include <iostream>
namespace gtsam {
class LinearEqualityManifoldFactorGraph: public FactorGraph<NonlinearFactor> {
public:
/// default constructor
LinearEqualityManifoldFactorGraph() {
}
/// linearize to a LinearEqualityFactorGraph
LinearEqualityFactorGraph::shared_ptr linearize(
const Values& linearizationPoint) const {
LinearEqualityFactorGraph::shared_ptr linearGraph(
new LinearEqualityFactorGraph());
BOOST_FOREACH(const NonlinearFactor::shared_ptr& factor, *this){
JacobianFactor::shared_ptr jacobian = boost::dynamic_pointer_cast<JacobianFactor>(
factor->linearize(linearizationPoint));
NonlinearConstraint::shared_ptr constraint = boost::dynamic_pointer_cast<NonlinearConstraint>(factor);
linearGraph->add(LinearEquality(*jacobian, constraint->dualKey()));
}
return linearGraph;
}
/**
* Return true if the max absolute error all factors is less than a tolerance
*/
bool checkFeasibility(const Values& values, double tol) const {
BOOST_FOREACH(const NonlinearFactor::shared_ptr& factor, *this){
NoiseModelFactor::shared_ptr noiseModelFactor = boost::dynamic_pointer_cast<NoiseModelFactor>(
factor);
Vector error = noiseModelFactor->unwhitenedError(values);
if (error.lpNorm<Eigen::Infinity>() > tol) {
return false;
}
}
return true;
}
};
class NonlinearEqualityFactorGraph: public LinearEqualityManifoldFactorGraph {
public:
/// default constructor
NonlinearEqualityFactorGraph() {
}
GaussianFactorGraph::shared_ptr multipliedHessians(const Values& values, const VectorValues& duals) const {
GaussianFactorGraph::shared_ptr constrainedHessians(new GaussianFactorGraph());
BOOST_FOREACH(const NonlinearFactor::shared_ptr& factor, *this) {
NonlinearConstraint::shared_ptr constraint = boost::dynamic_pointer_cast<NonlinearConstraint>(factor);
constrainedHessians->push_back(constraint->multipliedHessian(values, duals));
}
return constrainedHessians;
}
};
struct NLP {
NonlinearFactorGraph cost;
NonlinearEqualityFactorGraph linearEqualities;
NonlinearEqualityFactorGraph nonlinearEqualities;
};
struct SQPSimpleState {
Values values;
VectorValues duals;
bool converged;
size_t iterations;
/// Default constructor
SQPSimpleState() : values(), duals(), converged(false), iterations(0) {}
/// Constructor with an initialValues
SQPSimpleState(const Values& initialValues) :
values(initialValues), duals(VectorValues()), converged(false), iterations(0) {
}
};
/**
* Simple SQP optimizer to solve nonlinear constrained problems.
* This simple version won't care about nonconvexity, which needs
* more advanced techniques to solve, e.g., merit function, line search, second-order correction etc.
*/
class SQPSimple {
NLP nlp_;
static const double errorTol = 1e-5;
public:
SQPSimple(const NLP& nlp) :
nlp_(nlp) {
}
/// Check if \nabla f(x) - \lambda * \nabla c(x) == 0
bool isDualFeasible(const VectorValues& delta) const {
return delta.vector().lpNorm<Eigen::Infinity>() < errorTol;
// return false;
}
/// Check if c(x) == 0
bool isPrimalFeasible(const SQPSimpleState& state) const {
return nlp_.linearEqualities.checkFeasibility(state.values, errorTol)
&& nlp_.nonlinearEqualities.checkFeasibility(state.values, errorTol);
}
/// Check convergence
bool checkConvergence(const SQPSimpleState& state, const VectorValues& delta) const {
return isPrimalFeasible(state) & isDualFeasible(delta);
}
/**
* Single iteration of SQP
*/
SQPSimpleState iterate(const SQPSimpleState& state) const {
static const bool debug = true;
// construct the qp subproblem
QP qp;
qp.cost = *nlp_.cost.linearize(state.values);
GaussianFactorGraph::shared_ptr multipliedHessians = nlp_.nonlinearEqualities.multipliedHessians(state.values, state.duals);
qp.cost.push_back(*multipliedHessians);
qp.equalities.add(*nlp_.linearEqualities.linearize(state.values));
qp.equalities.add(*nlp_.nonlinearEqualities.linearize(state.values));
if (debug)
qp.print("QP subproblem:");
// solve the QP subproblem
VectorValues delta, duals;
QPSolver qpSolver(qp);
boost::tie(delta, duals) = qpSolver.optimize();
if (debug)
delta.print("delta = ");
if (debug)
duals.print("duals = ");
// update new state
SQPSimpleState newState;
newState.values = state.values.retract(delta);
newState.duals = duals;
newState.converged = checkConvergence(newState, delta);
newState.iterations = state.iterations + 1;
return newState;
}
VectorValues initializeDuals() const {
VectorValues duals;
BOOST_FOREACH(const NonlinearFactor::shared_ptr& factor, nlp_.linearEqualities) {
NonlinearConstraint::shared_ptr constraint = boost::dynamic_pointer_cast<NonlinearConstraint>(factor);
duals.insert(constraint->dualKey(), zero(factor->dim()));
}
BOOST_FOREACH(const NonlinearFactor::shared_ptr& factor, nlp_.nonlinearEqualities) {
NonlinearConstraint::shared_ptr constraint = boost::dynamic_pointer_cast<NonlinearConstraint>(factor);
duals.insert(constraint->dualKey(), zero(factor->dim()));
}
return duals;
}
/**
* Main optimization function.
*/
std::pair<Values, VectorValues> optimize(const Values& initialValues) const {
SQPSimpleState state(initialValues);
state.duals = initializeDuals();
while (!state.converged && state.iterations < 100) {
state = iterate(state);
}
return std::make_pair(state.values, state.duals);
}
};
}
#include <gtsam/slam/PriorFactor.h>
#include <gtsam/geometry/Pose3.h>
#include <gtsam/base/numericalDerivative.h>
using namespace std;
using namespace gtsam::symbol_shorthand;
using namespace gtsam;
const double tol = 1e-10;
//******************************************************************************
// x + y - 1 = 0
class ConstraintProblem1 : public NonlinearConstraint2<double, double> {
typedef NonlinearConstraint2<double, double> Base;
public:
ConstraintProblem1(Key xK, Key yK, Key dualKey) : Base(xK, yK, dualKey, 1) {}
// x + y - 1
Vector evaluateError(const double& x, const double& y,
boost::optional<Matrix&> H1 = boost::none, boost::optional<Matrix&> H2 =
boost::none) const {
if (H1) *H1 = eye(1);
if (H2) *H2 = eye(1);
return (Vector(1) << x + y - 1.0).finished();
}
};
TEST(testSQPSimple, QPProblem) {
const Key dualKey = 0;
// Simple quadratic cost: x1^2 + x2^2
// Note the Hessian encodes:
// 0.5*x1'*G11*x1 + x1'*G12*x2 + 0.5*x2'*G22*x2 - x1'*g1 - x2'*g2 + 0.5*f
// Hence here we have G11 = 2, G12 = 0, G22 = 2, g1 = 0, g2 = 0, f = 0
HessianFactor hf(X(1), Y(1), 2.0 * ones(1,1), zero(1), zero(1),
2*ones(1,1), zero(1) , 0);
LinearEqualityFactorGraph equalities;
LinearEquality linearConstraint(X(1), ones(1), Y(1), ones(1), 1*ones(1), dualKey); // x + y - 1 = 0
equalities.push_back(linearConstraint);
// Compare against QP
QP qp;
qp.cost.add(hf);
qp.equalities = equalities;
// instantiate QPsolver
QPSolver qpSolver(qp);
// create initial values for optimization
VectorValues initialVectorValues;
initialVectorValues.insert(X(1), zero(1));
initialVectorValues.insert(Y(1), ones(1));
VectorValues expectedSolution = qpSolver.optimize(initialVectorValues).first;
//Instantiate NLP
NLP nlp;
Values linPoint;
linPoint.insert<Vector1>(X(1), zero(1));
linPoint.insert<Vector1>(Y(1), zero(1));
nlp.cost.add(LinearContainerFactor(hf, linPoint)); // wrap it using linearcontainerfactor
nlp.linearEqualities.add(ConstraintProblem1(X(1), Y(1), dualKey));
Values initialValues;
initialValues.insert(X(1), 0.0);
initialValues.insert(Y(1), 0.0);
// Instantiate SQP
SQPSimple sqpSimple(nlp);
Values actualValues = sqpSimple.optimize(initialValues).first;
DOUBLES_EQUAL(expectedSolution.at(X(1))[0], actualValues.at<double>(X(1)), 1e-100);
DOUBLES_EQUAL(expectedSolution.at(Y(1))[0], actualValues.at<double>(Y(1)), 1e-100);
}
//******************************************************************************
class CircleConstraint : public NonlinearConstraint2<double, double> {
typedef NonlinearConstraint2<double, double> Base;
public:
CircleConstraint(Key xK, Key yK, Key dualKey) : Base(xK, yK, dualKey, 1) {}
Vector evaluateError(const double& x, const double& y,
boost::optional<Matrix&> H1 = boost::none, boost::optional<Matrix&> H2 =
boost::none) const {
if (H1) *H1 = (Matrix(1,1) << 2*(x-1)).finished();
if (H2) *H2 = (Matrix(1,1) << 2*y).finished();
return (Vector(1) << (x-1)*(x-1) + y*y - 0.25).finished();
}
void evaluateHessians(const double& x, const double& y,
std::vector<Matrix>& G11, std::vector<Matrix>& G12,
std::vector<Matrix>& G22) const {
G11.push_back((Matrix(1,1) << 2).finished());
G12.push_back((Matrix(1,1) << 0).finished());
G22.push_back((Matrix(1,1) << 2).finished());
}
};
TEST_UNSAFE(testSQPSimple, quadraticCostNonlinearConstraint) {
const Key dualKey = 0;
//Instantiate NLP
NLP nlp;
// Simple quadratic cost: x1^2 + x2^2 +1000
// Note the Hessian encodes:
// 0.5*x1'*G11*x1 + x1'*G12*x2 + 0.5*x2'*G22*x2 - x1'*g1 - x2'*g2 + 0.5*f
// Hence here we have G11 = 2, G12 = 0, G22 = 2, g1 = 0, g2 = 0, f = 0
Values linPoint;
linPoint.insert<Vector1>(X(1), zero(1));
linPoint.insert<Vector1>(Y(1), zero(1));
HessianFactor hf(X(1), Y(1), 2.0 * ones(1,1), zero(1), zero(1),
2*ones(1,1), zero(1) , 1000);
nlp.cost.add(LinearContainerFactor(hf, linPoint)); // wrap it using linearcontainerfactor
nlp.nonlinearEqualities.add(CircleConstraint(X(1), Y(1), dualKey));
Values initialValues;
initialValues.insert<double>(X(1), 4.0);
initialValues.insert<double>(Y(1), 10.0);
Values expectedSolution;
expectedSolution.insert<double>(X(1), 0.5);
expectedSolution.insert<double>(Y(1), 0.0);
// Instantiate SQP
SQPSimple sqpSimple(nlp);
Values actualSolution = sqpSimple.optimize(initialValues).first;
CHECK(assert_equal(expectedSolution, actualSolution, 1e-10));
actualSolution.print("actualSolution: ");
}
//******************************************************************************
class LineConstraintX : public NonlinearConstraint1<Pose3> {
typedef NonlinearConstraint1<Pose3> Base;
public:
LineConstraintX(Key key, Key dualKey) : Base(key, dualKey, 1) {
}
double computeError(const Pose3& pose) const {
return pose.x();
}
Vector evaluateError(const Pose3& pose, boost::optional<Matrix&> H = boost::none) const {
if (H)
*H = (Matrix(1,6) << zeros(1,3), pose.rotation().matrix().row(0)).finished();
return (Vector(1) << pose.x()).finished();
}
};
TEST_UNSAFE(testSQPSimple, poseOnALine) {
const Key dualKey = 0;
//Instantiate NLP
NLP nlp;
nlp.cost.add(PriorFactor<Pose3>(X(1), Pose3(Rot3::ypr(0.1, 0.2, 0.3), Point3(1, 0, 0)), noiseModel::Unit::Create(6)));
LineConstraintX constraint(X(1), dualKey);
nlp.nonlinearEqualities.add(constraint);
Values initialValues;
initialValues.insert(X(1), Pose3(Rot3::ypr(0.3, 0.2, 0.3), Point3(1,0,0)));
Values expectedSolution;
expectedSolution.insert(X(1), Pose3(Rot3::ypr(0.1, 0.2, 0.3), Point3()));
// Instantiate SQP
SQPSimple sqpSimple(nlp);
Values actualSolution = sqpSimple.optimize(initialValues).first;
CHECK(assert_equal(expectedSolution, actualSolution, 1e-10));
actualSolution.print("actualSolution: ");
Pose3 pose(Rot3::ypr(0.1, 0.2, 0.3), Point3());
Matrix hessian = numericalHessian<Pose3>(boost::bind(&LineConstraintX::computeError, constraint, _1), pose, 1e-2);
cout << "hessian: \n" << hessian << endl;
}
//******************************************************************************
int main() {
TestResult tr;
return TestRegistry::runAllTests(tr);
}
//******************************************************************************