>> whos
  Name                 Size            Bytes  Class
  graph                1x1               112  gtsam.NonlinearFactorGraph
  priorNoise           1x1               112  gtsam.noiseModel.Diagonal
  model                1x1               112  gtsam.noiseModel.Diagonal
  initialEstimate      1x1               112  gtsam.Values                                   
  optimizer            1x1               112  gtsam.LevenbergMarquardtOptimizer