test_Pose3SLAMExample.py

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"""
GTSAM Copyright 2010-2019, Georgia Tech Research Corporation,
Atlanta, Georgia 30332-0415
All Rights Reserved
 
See LICENSE for the license information
 
PoseSLAM unit tests.
Author: Frank Dellaert & Duy Nguyen Ta (Python)
"""
import unittest
from math import pi
 
import numpy as np
 
import gtsam
from gtsam.utils.test_case import GtsamTestCase
from gtsam.utils.circlePose3 import circlePose3
 
 
class TestPose3SLAMExample(GtsamTestCase):
 
    def test_Pose3SLAMExample(self) -> None:
        # Create a hexagon of poses
        hexagon = circlePose3(numPoses=6, radius=1.0)
        p0 = hexagon.atPose3(0)
        p1 = hexagon.atPose3(1)
 
        # create a Pose graph with one equality constraint and one measurement
        fg = gtsam.NonlinearFactorGraph()
        fg.add(gtsam.NonlinearEqualityPose3(0, p0))
        delta = p0.between(p1)
        covariance = gtsam.noiseModel.Diagonal.Sigmas(
            np.array([0.05, 0.05, 0.05, np.deg2rad(5.), np.deg2rad(5.), np.deg2rad(5.)]))
        fg.add(gtsam.BetweenFactorPose3(0, 1, delta, covariance))
        fg.add(gtsam.BetweenFactorPose3(1, 2, delta, covariance))
        fg.add(gtsam.BetweenFactorPose3(2, 3, delta, covariance))
        fg.add(gtsam.BetweenFactorPose3(3, 4, delta, covariance))
        fg.add(gtsam.BetweenFactorPose3(4, 5, delta, covariance))
        fg.add(gtsam.BetweenFactorPose3(5, 0, delta, covariance))
 
        # Create initial config
        initial = gtsam.Values()
        s = 0.10
        initial.insert(0, p0)
        initial.insert(1, hexagon.atPose3(1).retract(s * np.random.randn(6, 1)))
        initial.insert(2, hexagon.atPose3(2).retract(s * np.random.randn(6, 1)))
        initial.insert(3, hexagon.atPose3(3).retract(s * np.random.randn(6, 1)))
        initial.insert(4, hexagon.atPose3(4).retract(s * np.random.randn(6, 1)))
        initial.insert(5, hexagon.atPose3(5).retract(s * np.random.randn(6, 1)))
 
        # optimize
        optimizer = gtsam.LevenbergMarquardtOptimizer(fg, initial)
        result = optimizer.optimizeSafely()
 
        pose_1 = result.atPose3(1)
        self.gtsamAssertEquals(pose_1, p1, 1e-4)
 
if __name__ == "__main__":
    unittest.main()