gtsam/cpp/testPose2Factor.cpp

138 lines
4.2 KiB
C++

/**
* @file testPose2Factor.cpp
* @brief Unit tests for Pose2Factor Class
* @authors Frank Dellaert, Viorela Ila
**/
#include <CppUnitLite/TestHarness.h>
#define GTSAM_MAGIC_KEY
#include "numericalDerivative.h"
#include "pose2SLAM.h"
using namespace std;
using namespace gtsam;
// Common measurement covariance
static double sx=0.5, sy=0.5,st=0.1;
static noiseModel::Gaussian::shared_ptr covariance(
noiseModel::Gaussian::Covariance(Matrix_(3, 3,
sx*sx, 0.0, 0.0,
0.0, sy*sy, 0.0,
0.0, 0.0, st*st
)));
/* ************************************************************************* */
// Very simple test establishing Ax-b \approx z-h(x)
TEST( Pose2Factor, error )
{
// Choose a linearization point
Pose2 p1; // robot at origin
Pose2 p2(1, 0, 0); // robot at (1,0)
Pose2Config x0;
x0.insert(1, p1);
x0.insert(2, p2);
// Create factor
Pose2 z = between(p1,p2);
Pose2Factor factor(1, 2, z, covariance);
// Actual linearization
boost::shared_ptr<GaussianFactor> linear = factor.linearize(x0);
// Check error at x0, i.e. delta = zero !
VectorConfig delta;
delta.insert("x1", zero(3));
delta.insert("x2", zero(3));
Vector error_at_zero = Vector_(3,0.0,0.0,0.0);
CHECK(assert_equal(error_at_zero,factor.unwhitenedError(x0)));
CHECK(assert_equal(-error_at_zero,linear->error_vector(delta)));
// Check error after increasing p2
VectorConfig plus = delta;
plus.insertAdd("x2", Vector_(3, 0.1, 0.0, 0.0));
Pose2Config x1 = expmap(x0, plus);
Vector error_at_plus = Vector_(3,0.1/sx,0.0,0.0); // h(x)-z = 0.1 !
CHECK(assert_equal(error_at_plus,factor.whitenedError(x1)));
CHECK(assert_equal(error_at_plus,linear->error_vector(plus)));
}
/* ************************************************************************* */
// common Pose2Factor for tests below
static Pose2 measured(2,2,M_PI_2);
static Pose2Factor factor(1,2,measured, covariance);
/* ************************************************************************* */
TEST( Pose2Factor, rhs )
{
// Choose a linearization point
Pose2 p1(1.1,2,M_PI_2); // robot at (1.1,2) looking towards y (ground truth is at 1,2, see testPose2)
Pose2 p2(-1,4.1,M_PI); // robot at (-1,4.1) looking at negative (ground truth is at -1,4)
Pose2Config x0;
x0.insert(1,p1);
x0.insert(2,p2);
// Actual linearization
boost::shared_ptr<GaussianFactor> linear = factor.linearize(x0);
// Check RHS
Pose2 hx0 = between(p1,p2);
CHECK(assert_equal(Pose2(2.1, 2.1, M_PI_2),hx0));
Vector expected_b = Vector_(3, -0.1/sx, 0.1/sy, 0.0);
CHECK(assert_equal(expected_b,-factor.whitenedError(x0)));
CHECK(assert_equal(expected_b,linear->get_b()));
}
/* ************************************************************************* */
// The error |A*dx-b| approximates (h(x0+dx)-z) = -error_vector
// Hence i.e., b = approximates z-h(x0) = error_vector(x0)
Vector h(const Pose2& p1,const Pose2& p2) {
return covariance->whiten(factor.evaluateError(p1,p2));
}
/* ************************************************************************* */
TEST( Pose2Factor, linearize )
{
// Choose a linearization point at ground truth
Pose2 p1(1,2,M_PI_2);
Pose2 p2(-1,4,M_PI);
Pose2Config x0;
x0.insert(1,p1);
x0.insert(2,p2);
// expected linearization
Matrix expectedH1 = covariance->Whiten(Matrix_(3,3,
0.0,-1.0,-2.0,
1.0, 0.0,-2.0,
0.0, 0.0,-1.0
));
Matrix expectedH2 = covariance->Whiten(Matrix_(3,3,
1.0, 0.0, 0.0,
0.0, 1.0, 0.0,
0.0, 0.0, 1.0
));
Vector expected_b = Vector_(3, 0.0, 0.0, 0.0);
// expected linear factor
SharedDiagonal probModel1 = noiseModel::Unit::Create(3);
GaussianFactor expected("x1", expectedH1, "x2", expectedH2, expected_b, probModel1);
// Actual linearization
boost::shared_ptr<GaussianFactor> actual = factor.linearize(x0);
CHECK(assert_equal(expected,*actual));
// Numerical do not work out because BetweenFactor is approximate ?
Matrix numericalH1 = numericalDerivative21(h, p1, p2, 1e-5);
CHECK(assert_equal(expectedH1,numericalH1));
Matrix numericalH2 = numericalDerivative22(h, p1, p2, 1e-5);
CHECK(assert_equal(expectedH2,numericalH2));
}
/* ************************************************************************* */
int main() {
TestResult tr;
return TestRegistry::runAllTests(tr);
}
/* ************************************************************************* */