gtsam/tests/testSubgraphPreconditioner.cpp

226 lines
7.7 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 testSubgraphConditioner.cpp
* @brief Unit tests for SubgraphPreconditioner
* @author Frank Dellaert
**/
#include <CppUnitLite/TestHarness.h>
#if 0
#include <tests/smallExample.h>
#include <gtsam/inference/Symbol.h>
#include <gtsam/linear/iterative.h>
#include <gtsam/linear/GaussianFactorGraph.h>
#include <gtsam/linear/SubgraphPreconditioner.h>
#include <gtsam/inference/Ordering.h>
#include <gtsam/base/numericalDerivative.h>
#include <boost/foreach.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/assign/std/list.hpp>
using namespace boost::assign;
using namespace std;
using namespace gtsam;
using namespace example;
// define keys
// Create key for simulated planar graph
Symbol key(int x, int y) {
return symbol_shorthand::X(1000*x+y);
}
/* ************************************************************************* */
TEST( SubgraphPreconditioner, planarOrdering ) {
// Check canonical ordering
Ordering expected, ordering = planarOrdering(3);
expected +=
key(3, 3), key(2, 3), key(1, 3),
key(3, 2), key(2, 2), key(1, 2),
key(3, 1), key(2, 1), key(1, 1);
CHECK(assert_equal(expected,ordering));
}
/* ************************************************************************* */
/** unnormalized error */
static double error(const GaussianFactorGraph& fg, const VectorValues& x) {
double total_error = 0.;
BOOST_FOREACH(const GaussianFactor::shared_ptr& factor, fg)
total_error += factor->error(x);
return total_error;
}
/* ************************************************************************* */
TEST( SubgraphPreconditioner, planarGraph )
{
// Check planar graph construction
GaussianFactorGraph A;
VectorValues xtrue;
boost::tie(A, xtrue) = planarGraph(3);
LONGS_EQUAL(13,A.size());
LONGS_EQUAL(9,xtrue.size());
DOUBLES_EQUAL(0,error(A,xtrue),1e-9); // check zero error for xtrue
// Check that xtrue is optimal
GaussianBayesNet::shared_ptr R1 = GaussianSequentialSolver(A).eliminate();
VectorValues actual = optimize(*R1);
CHECK(assert_equal(xtrue,actual));
}
/* ************************************************************************* */
TEST( SubgraphPreconditioner, splitOffPlanarTree )
{
// Build a planar graph
GaussianFactorGraph A;
VectorValues xtrue;
boost::tie(A, xtrue) = planarGraph(3);
// Get the spanning tree and constraints, and check their sizes
GaussianFactorGraph T, C;
boost::tie(T, C) = splitOffPlanarTree(3, A);
LONGS_EQUAL(9,T.size());
LONGS_EQUAL(4,C.size());
// Check that the tree can be solved to give the ground xtrue
GaussianBayesNet::shared_ptr R1 = GaussianSequentialSolver(T).eliminate();
VectorValues xbar = optimize(*R1);
CHECK(assert_equal(xtrue,xbar));
}
/* ************************************************************************* */
TEST( SubgraphPreconditioner, system )
{
// Build a planar graph
GaussianFactorGraph Ab;
VectorValues xtrue;
size_t N = 3;
boost::tie(Ab, xtrue) = planarGraph(N); // A*x-b
// Get the spanning tree and corresponding ordering
GaussianFactorGraph Ab1_, Ab2_; // A1*x-b1 and A2*x-b2
boost::tie(Ab1_, Ab2_) = splitOffPlanarTree(N, Ab);
SubgraphPreconditioner::sharedFG Ab1(new GaussianFactorGraph(Ab1_));
SubgraphPreconditioner::sharedFG Ab2(new GaussianFactorGraph(Ab2_));
// Eliminate the spanning tree to build a prior
SubgraphPreconditioner::sharedBayesNet Rc1 = GaussianSequentialSolver(Ab1_).eliminate(); // R1*x-c1
VectorValues xbar = optimize(*Rc1); // xbar = inv(R1)*c1
// Create Subgraph-preconditioned system
VectorValues::shared_ptr xbarShared(new VectorValues(xbar)); // TODO: horrible
SubgraphPreconditioner system(Ab2, Rc1, xbarShared);
// Create zero config
VectorValues zeros = VectorValues::Zero(xbar);
// Set up y0 as all zeros
VectorValues y0 = zeros;
// y1 = perturbed y0
VectorValues y1 = zeros;
y1[1] = (Vector(2) << 1.0, -1.0);
// Check corresponding x values
VectorValues expected_x1 = xtrue, x1 = system.x(y1);
expected_x1[1] = (Vector(2) << 2.01, 2.99);
expected_x1[0] = (Vector(2) << 3.01, 2.99);
CHECK(assert_equal(xtrue, system.x(y0)));
CHECK(assert_equal(expected_x1,system.x(y1)));
// Check errors
DOUBLES_EQUAL(0,error(Ab,xtrue),1e-9);
DOUBLES_EQUAL(3,error(Ab,x1),1e-9);
DOUBLES_EQUAL(0,error(system,y0),1e-9);
DOUBLES_EQUAL(3,error(system,y1),1e-9);
// Test gradient in x
VectorValues expected_gx0 = zeros;
VectorValues expected_gx1 = zeros;
CHECK(assert_equal(expected_gx0,gradient(Ab,xtrue)));
expected_gx1[2] = (Vector(2) << -100., 100.);
expected_gx1[4] = (Vector(2) << -100., 100.);
expected_gx1[1] = (Vector(2) << 200., -200.);
expected_gx1[3] = (Vector(2) << -100., 100.);
expected_gx1[0] = (Vector(2) << 100., -100.);
CHECK(assert_equal(expected_gx1,gradient(Ab,x1)));
// Test gradient in y
VectorValues expected_gy0 = zeros;
VectorValues expected_gy1 = zeros;
expected_gy1[2] = (Vector(2) << 2., -2.);
expected_gy1[4] = (Vector(2) << -2., 2.);
expected_gy1[1] = (Vector(2) << 3., -3.);
expected_gy1[3] = (Vector(2) << -1., 1.);
expected_gy1[0] = (Vector(2) << 1., -1.);
CHECK(assert_equal(expected_gy0,gradient(system,y0)));
CHECK(assert_equal(expected_gy1,gradient(system,y1)));
// Check it numerically for good measure
// TODO use boost::bind(&SubgraphPreconditioner::error,&system,_1)
// Vector numerical_g1 = numericalGradient<VectorValues> (error, y1, 0.001);
// Vector expected_g1 = (Vector(18) << 0., 0., 0., 0., 2., -2., 0., 0., -2., 2.,
// 3., -3., 0., 0., -1., 1., 1., -1.);
// CHECK(assert_equal(expected_g1,numerical_g1));
}
/* ************************************************************************* */
TEST( SubgraphPreconditioner, conjugateGradients )
{
// Build a planar graph
GaussianFactorGraph Ab;
VectorValues xtrue;
size_t N = 3;
boost::tie(Ab, xtrue) = planarGraph(N); // A*x-b
// Get the spanning tree and corresponding ordering
GaussianFactorGraph Ab1_, Ab2_; // A1*x-b1 and A2*x-b2
boost::tie(Ab1_, Ab2_) = splitOffPlanarTree(N, Ab);
SubgraphPreconditioner::sharedFG Ab1(new GaussianFactorGraph(Ab1_));
SubgraphPreconditioner::sharedFG Ab2(new GaussianFactorGraph(Ab2_));
// Eliminate the spanning tree to build a prior
Ordering ordering = planarOrdering(N);
SubgraphPreconditioner::sharedBayesNet Rc1 = GaussianSequentialSolver(Ab1_).eliminate(); // R1*x-c1
VectorValues xbar = optimize(*Rc1); // xbar = inv(R1)*c1
// Create Subgraph-preconditioned system
VectorValues::shared_ptr xbarShared(new VectorValues(xbar)); // TODO: horrible
SubgraphPreconditioner system(Ab2, Rc1, xbarShared);
// Create zero config y0 and perturbed config y1
VectorValues y0 = VectorValues::Zero(xbar);
VectorValues y1 = y0;
y1[1] = (Vector(2) << 1.0, -1.0);
VectorValues x1 = system.x(y1);
// Solve for the remaining constraints using PCG
ConjugateGradientParameters parameters;
VectorValues actual = conjugateGradients<SubgraphPreconditioner,
VectorValues, Errors>(system, y1, parameters);
CHECK(assert_equal(y0,actual));
// Compare with non preconditioned version:
VectorValues actual2 = conjugateGradientDescent(Ab, x1, parameters);
CHECK(assert_equal(xtrue,actual2,1e-4));
}
#endif
/* ************************************************************************* */
int main() { TestResult tr; return TestRegistry::runAllTests(tr); }
/* ************************************************************************* */