cylinder_offset)
        fs.correct(cylinders)

        # Output particles.
        print_particles(fs.particles, f)

        # Output state estimated from all particles.
        mean = get_mean(fs.particles)
        print >> f, "F %.0f %.0f %.3f" %\
              (mean[0] + scanner_displacement * cos(mean[2]),
               mean[1] + scanner_displacement * sin(mean[2]),
               mean[2])

        # Output error ellipse and standard deviation of heading.
        errors = get_error_ellipse_and_heading_variance(fs.particles, mean)
        print >> f, "E %.3f %.0f %.0f %.3f" % errors

        # Output landmarks of particle which is closest to the mean position.
        output_particle = min([
            (np.linalg.norm(mean[0:2] - fs.particles[i].pose[0:2]), i)
            for i in xrange(len(fs.particles))
        ])[1]
        # Write estimates of landmarks.
        write_cylinders(f, "W C",
                        fs.particles[output_particle].landmark_positions)
        # Write covariance matrices.
        write_error_ellipses(
            f, "W E", fs.particles[output_particle].landmark_covariances)

    f.close()
        cylinders = get_cylinders_from_scan(logfile.scan_data[i], depth_jump,
            minimum_valid_distance, cylinder_offset)
        fs.correct(cylinders)

        # Output particles.
        print_particles(fs.particles, f)

        # Output state estimated from all particles.
        mean = get_mean(fs.particles)
        print >> f, "F %.0f %.0f %.3f" %\
              (mean[0] + scanner_displacement * cos(mean[2]),
               mean[1] + scanner_displacement * sin(mean[2]),
               mean[2])

        # Output error ellipse and standard deviation of heading.
        errors = get_error_ellipse_and_heading_variance(fs.particles, mean)
        print >> f, "E %.3f %.0f %.0f %.3f" % errors

        # Output landmarks of particle which is closest to the mean position.
        output_particle = min([
            (np.linalg.norm(mean[0:2] - fs.particles[i].pose[0:2]),i)
            for i in xrange(len(fs.particles)) ])[1]
        # Write estimates of landmarks.
        write_cylinders(f, "W C",
                        fs.particles[output_particle].landmark_positions)
        # Write covariance matrices.
        write_error_ellipses(f, "W E",
                             fs.particles[output_particle].landmark_covariances)

    f.close()