text: #!/usr/bin/python
  
  import os
  import sys
  import time
  import rospkg
  import numpy as np
  import matplotlib.pyplot as plt
  import yaml
  import argparse
  from matplotlib import rc
  
  # tell matplotlib to use latex font
  rc('font',**{'family':'serif','serif':['Cardo']})
  rc('text', usetex=True)    
    
  from mpl_toolkits.axes_grid1.inset_locator import zoomed_inset_axes
  from mpl_toolkits.axes_grid1.inset_locator import mark_inset
  
  def plot_trajectory(ax, filename, label, color, linewidth):
    file = open(filename)
    data = file.read()
    lines = data.replace(","," ").replace("\t"," ").split("\n")
    trajectory = np.array([[v.strip() for v in line.split(" ") if v.strip()!=""] for line in lines if len(line)>0 and line[0]!="#"], dtype=np.float64)
    ax.plot(trajectory[:,1], trajectory[:,2], label=label, color=color, linewidth=linewidth)
  
  def compare_results(experiments, results_dir, comparison_dir, 
                      plot_scale_drift = False):
    
    # ------------------------------------------------------------------------------
    # position error 
    fig_poserr = plt.figure(figsize=(8,6))
    ax_poserr_x = fig_poserr.add_subplot(311, ylabel='x-error [m]')
    ax_poserr_y = fig_poserr.add_subplot(312, ylabel='y-error [m]')
    ax_poserr_z = fig_poserr.add_subplot(313, ylabel='z-error [m]', xlabel='time [s]')
    
    for exp in experiments:
      
      # load dataset parameters
      params_stream = open(os.path.join(results_dir, exp, 'params.yaml'))
      params = yaml.load(params_stream)
    
      # plot translation error
      trans_error = np.loadtxt(os.path.join(results_dir, exp, 'translation_error.txt'))
      trans_error[:,0] = trans_error[:,0]-trans_error[0,0]
      ax_poserr_x.plot(trans_error[:,0], trans_error[:,1], label=params['experiment_label'])
      ax_poserr_y.plot(trans_error[:,0], trans_error[:,2])
      ax_poserr_z.plot(trans_error[:,0], trans_error[:,3])
      
    ax_poserr_x.set_xlim([0, trans_error[-1,0]+4])
    ax_poserr_y.set_xlim([0, trans_error[-1,0]+4]) 
    ax_poserr_z.set_xlim([0, trans_error[-1,0]+4])
    ax_poserr_x.legend(bbox_to_anchor=[0, 0], loc='lower left', ncol=3)
    ax_poserr_x.grid()
    ax_poserr_y.grid()
    ax_poserr_z.grid()
    fig_poserr.tight_layout()
    fig_poserr.savefig(os.path.join(comparison_dir, 'translation_error.pdf'))
    
    # ------------------------------------------------------------------------------
    # orientation error 
    fig_roterr = plt.figure(figsize=(8,6))
    ax_roterr_r = fig_roterr.add_subplot(311, ylabel='roll-error [rad]')
    ax_roterr_p = fig_roterr.add_subplot(312, ylabel='pitch-error [rad]')
    ax_roterr_y = fig_roterr.add_subplot(313, ylabel='yaw-error [rad]', xlabel='time [s]')
    
    for exp in experiments:
      
      # load dataset parameters
      params_stream = open(os.path.join(results_dir, exp, 'params.yaml'))
      params = yaml.load(params_stream)
    
      # plot translation error
      rot_error = np.loadtxt(os.path.join(results_dir, exp, 'orientation_error.txt'))
      rot_error[:,0] = rot_error[:,0]-rot_error[0,0]
      ax_roterr_r.plot(rot_error[:,0], rot_error[:,3], label=params['experiment_label'])
      ax_roterr_p.plot(rot_error[:,0], rot_error[:,2])
      ax_roterr_y.plot(rot_error[:,0], rot_error[:,1])
      
    ax_roterr_r.set_xlim([0, rot_error[-1,0]+4])
    ax_roterr_p.set_xlim([0, rot_error[-1,0]+4])
    ax_roterr_y.set_xlim([0, rot_error[-1,0]+4])
    ax_roterr_r.legend(bbox_to_anchor=[0, 1], loc='upper left', ncol=3)
    ax_roterr_r.grid()
    ax_roterr_p.grid()
    ax_roterr_y.grid()
    fig_roterr.tight_layout()
    fig_roterr.savefig(os.path.join(comparison_dir, 'orientation_error.pdf'))
    
    # ------------------------------------------------------------------------------
    # scale error 
    if plot_scale_drift:
      fig_scale = plt.figure(figsize=(8,2.5))
      ax_scale = fig_scale.add_subplot(111, xlabel='time [s]', ylabel='scale change [\%]')
      
      for exp in experiments:
        
        # load dataset parameters
        params = yaml.load(open(os.path.join(results_dir, exp, 'params.yaml')))
      
        # plot translation error
        scale_drift = open(os.path.join(results_dir, exp, 'scale_drift.txt'))
        scale_drift[:,0] = scale_drift[:,0]-scale_drift[0,0]
        ax_scale.plot(scale_drift[:,0], scale_drift[:,1], label=params['experiment_label'])
    
      ax_scale.set_xlim([0, rot_error[-1,0]+4])
      ax_scale.legend(bbox_to_anchor=[0, 1], loc='upper left', ncol=3)
      ax_scale.grid()
      fig_scale.tight_layout()
      fig_scale.savefig(os.path.join(comparison_dir, 'scale_drift.pdf'))
    
    # ------------------------------------------------------------------------------
    # trajectory
    
  #   fig_traj = plt.figure(figsize=(8,4.8))
  #   ax_traj = fig_traj.add_subplot(111, xlabel='x [m]', ylabel='y [m]', aspect='equal', xlim=[-3.1, 4], ylim=[-1.5, 2.6])
  # 
  #   plotTrajectory(ax_traj, '/home/cforster/Datasets/asl_vicon_d2/groundtruth_filtered.txt', 'Groundtruth', 'k', 1.5)
  #   plotTrajectory(ax_traj, results_dir+'/20130911_2229_nslam_i7_asl2_fast/traj_estimate_rotated.txt', 'Fast', 'g', 1)
  #   plotTrajectory(ax_traj, results_dir+'/20130906_2149_ptam_i7_asl2/traj_estimate_rotated.txt', 'PTAM', 'r', 1)
  # 
  #   mark_inset(ax_traj, axins, loc1=2, loc2=4, fc="none", ec='b')
  #   plt.draw()
  #   plt.show() 
  #   ax_traj.legend(bbox_to_anchor=[1, 0], loc='lower right', ncol=3)
  #   ax_traj.grid()
  #   fig_traj.tight_layout()
  #   fig_traj.savefig('../results/trajectory_asl.pdf')
    
    
  if __name__ == '__main__':
    
    default_name = time.strftime("%Y%m%d_%H%M", time.localtime())+'_comparison'
    parser = argparse.ArgumentParser(description='Compare results.')
    parser.add_argument('result_directories', nargs='+', help='list of result directories to compare')
    parser.add_argument('--name', help='name of the comparison', default=default_name)
    args = parser.parse_args()
   
    # create folder for comparison results
    results_dir = os.path.join(rospkg.RosPack().get_path('svo_analysis'), 'results')
    comparison_dir = os.path.join(results_dir, args.name)
    if not os.path.exists(comparison_dir):
      os.makedirs(comparison_dir)
      
    # run comparison
    compare_results(args.result_directories, results_dir, comparison_dir) 
    
   
                   
             
  