gtsam/gtsam/linear/SubgraphSolver.cpp

138 lines
5.1 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
* -------------------------------------------------------------------------- */
#include <gtsam/linear/Errors.h>
#include <gtsam/linear/GaussianConditional.h>
#include <gtsam/linear/GaussianBayesNet.h>
#include <gtsam/linear/GaussianFactorGraph.h>
#include <gtsam/linear/iterative-inl.h>
#include <gtsam/linear/GaussianFactorGraph.h>
#include <gtsam/linear/SubgraphSolver.h>
#include <gtsam/linear/VectorValues.h>
#include <gtsam/inference/graph-inl.h>
#include <gtsam/inference/EliminationTree.h>
#include <gtsam/base/DSFVector.h>
#include <boost/foreach.hpp>
#include <boost/shared_ptr.hpp>
#include <list>
using namespace std;
namespace gtsam {
/**************************************************************************************************/
SubgraphSolver::SubgraphSolver(const GaussianFactorGraph &gfg, const Parameters &parameters)
: parameters_(parameters)
{
initialize(gfg);
}
/**************************************************************************************************/
SubgraphSolver::SubgraphSolver(const GaussianFactorGraph::shared_ptr &jfg, const Parameters &parameters)
: parameters_(parameters)
{
initialize(*jfg);
}
/**************************************************************************************************/
SubgraphSolver::SubgraphSolver(const GaussianFactorGraph &Ab1, const GaussianFactorGraph &Ab2, const Parameters &parameters)
: parameters_(parameters) {
GaussianBayesNet::shared_ptr Rc1 = EliminationTree<GaussianFactor>::Create(Ab1)->eliminate(&EliminateQR);
initialize(Rc1, boost::make_shared<GaussianFactorGraph>(Ab2));
}
/**************************************************************************************************/
SubgraphSolver::SubgraphSolver(const GaussianFactorGraph::shared_ptr &Ab1,
const GaussianFactorGraph::shared_ptr &Ab2, const Parameters &parameters)
: parameters_(parameters) {
GaussianBayesNet::shared_ptr Rc1 = EliminationTree<GaussianFactor>::Create(*Ab1)->eliminate(&EliminateQR);
initialize(Rc1, Ab2);
}
/**************************************************************************************************/
SubgraphSolver::SubgraphSolver(const GaussianBayesNet::shared_ptr &Rc1, const GaussianFactorGraph &Ab2,
const Parameters &parameters) : parameters_(parameters)
{
initialize(Rc1, boost::make_shared<GaussianFactorGraph>(Ab2));
}
/**************************************************************************************************/
SubgraphSolver::SubgraphSolver(const GaussianBayesNet::shared_ptr &Rc1,
const GaussianFactorGraph::shared_ptr &Ab2, const Parameters &parameters) : parameters_(parameters)
{
initialize(Rc1, Ab2);
}
VectorValues SubgraphSolver::optimize() {
VectorValues ybar = conjugateGradients<SubgraphPreconditioner, VectorValues, Errors>(*pc_, pc_->zero(), parameters_);
return pc_->x(ybar);
}
void SubgraphSolver::initialize(const GaussianFactorGraph &jfg)
{
GaussianFactorGraph::shared_ptr Ab1 = boost::make_shared<GaussianFactorGraph>(),
Ab2 = boost::make_shared<GaussianFactorGraph>();
boost::tie(Ab1, Ab2) = splitGraph(jfg) ;
if (parameters_.verbosity())
cout << "Split A into (A1) " << Ab1->size() << " and (A2) " << Ab2->size() << " factors" << endl;
GaussianBayesNet::shared_ptr Rc1 = EliminationTree<GaussianFactor>::Create(*Ab1)->eliminate(&EliminateQR);
VectorValues::shared_ptr xbar(new VectorValues(gtsam::optimize(*Rc1)));
pc_ = boost::make_shared<SubgraphPreconditioner>(Ab2, Rc1, xbar);
}
void SubgraphSolver::initialize(const GaussianBayesNet::shared_ptr &Rc1, const GaussianFactorGraph::shared_ptr &Ab2)
{
VectorValues::shared_ptr xbar(new VectorValues(gtsam::optimize(*Rc1)));
pc_ = boost::make_shared<SubgraphPreconditioner>(Ab2, Rc1, xbar);
}
boost::tuple<GaussianFactorGraph::shared_ptr, GaussianFactorGraph::shared_ptr>
SubgraphSolver::splitGraph(const GaussianFactorGraph &jfg) {
const VariableIndex index(jfg);
const size_t n = index.size();
DSFVector D(n);
GaussianFactorGraph::shared_ptr At(new GaussianFactorGraph());
GaussianFactorGraph::shared_ptr Ac( new GaussianFactorGraph());
size_t t = 0;
BOOST_FOREACH ( const GaussianFactor::shared_ptr &gf, jfg ) {
if ( gf->keys().size() > 2 ) {
throw runtime_error("SubgraphSolver::splitGraph the graph is not simple, sanity check failed ");
}
bool augment = false ;
/* check whether this factor should be augmented to the "tree" graph */
if ( gf->keys().size() == 1 ) augment = true;
else {
const Index u = gf->keys()[0], v = gf->keys()[1],
u_root = D.findSet(u), v_root = D.findSet(v);
if ( u_root != v_root ) {
t++; augment = true ;
D.makeUnionInPlace(u_root, v_root);
}
}
if ( augment ) At->push_back(gf);
else Ac->push_back(gf);
}
return boost::tie(At, Ac);
}
} // \namespace gtsam