Description

Methods

####################################
#
# A granular Büttiker-Landauer motor, O. Devauchelle, P. Popović, P. Szymczak, A. Abramian & A. Lazarus (2026)
# Thermodynamics of bouncing grains, O. Devauchelle, P. Popović, P. Szymczak, A. Abramian & A. Lazarus (2026)  
# https://www.doi.org/10.5281/zenodo.18862698
# https://github.com/odevauchelle/BrownTrack
#
####################################

from pylab import *
from glob import glob
import json

sys.path.append('/home/olivier/git/BrownTrack/') 
import BrownTrack as BT

####################
#
# parameters & data
#
###################

file_to_letter = {'big_grains_40Hz': 'A', 'siloxane_multiple_quick_3': 'B', 'siloxane_big_grains_large_swing': 'C', 'siloxane_small_low_freq': 'D', 'siloxane_multiple_quick': 'E', 'siloxane_multiple_quick_2': 'F', 'siloxane_small_grains': 'G', 'siloxane_small_large_amp': 'H', 'diffusivity_hard_30Hz_1_5_mm': 'I', 'diffusivity_soft_30Hz_2_5_4_mm': 'J', 'diffusivity_hard_30Hz_2_5_4_mm': 'K', 'diffusivity_soft_30Hz_6_mm': 'L', 'diffusivity_hard_30Hz_6_mm': 'M', 'diffusivity_soft_30Hz_1_5_mm': 'N'}

experiment = 'siloxane_small_low_freq'
movie_index = 4


data_path = '/home/olivier/no_backup/ganzeville/Bureau/bouncing_grains/BL_ratchet_paper_data/BLR_experiment/'
experiment_folder = data_path + experiment
processed_data_path = experiment_folder + '/processed_data/'

with open( processed_data_path + 'parameters.json' ) as the_file :
	p = json.load( the_file )

with open( processed_data_path + 'domains.json' ) as the_file :
	domains_data = json.load( the_file )

###############################
#
# show domains
#
###############################

fig = figure( figsize = (6,6), layout = 'tight' )
ax_phys = gca()

domains = {}

for name, domain in domains_data['domains'].items() :

	patch_style = dict( facecolor = 'none', linestyle = '--' )

	if name == 'main' :
		patch_style['linestyle'] = '-'

	domains[name] = BT.domain( **domain )

	ax_phys.add_patch( domains[name].get_patch( label = name.capitalize(), **patch_style ) )

radius = domains['main'].boundary['radius']
disk_diameter = 8 # cm
disk_diameter *= 1e-2 #m
meters_per_pixel = disk_diameter/radius

###################
#
# draw scale bar
#
###################

px_per_cm = 1e-2/meters_per_pixel

bar_size = 1 #cm

bar_pos = array( domains['main'].boundary['xy'] ) + .92*array([1,-1])*radius

bar_points = array( [ bar_pos - array([bar_size*px_per_cm, 0]), bar_pos + array([bar_size*px_per_cm, 0]) ] )

bar_color = 'k'
ax_phys.plot( *bar_points.T, '-|', color = bar_color )
ax_phys.text( *( mean(bar_points, axis = 0) + array([0, 0]) ), str(bar_size) + r'$\,$cm' + '\n', color = bar_color, ha = 'center' )

####################
#
# plot trajectories
#
####################

def is_acceptable( traj, **criteria ) :

    output = True

    try :
        output = output and len(traj.x) > criteria['min_length']
    except :
        pass

    try :
        output = output and norm( array( [ ( traj.x[-1] - traj.x[0] ), ( traj.y[-1] - traj.y[0] ) ] ) ) > criteria['min_displacement']*p['grain_size']
    except :
        pass

    return output

data_file = glob( processed_data_path + 'bunch_*.traj' )[movie_index]

with open( data_file ) as the_file :
	p_traj = json.loads( the_file.readline() )
	traj_movie_name = p_traj['movie_file'].replace( 'diffusion_', '' )
	trajectories = BT.load_trajectories( the_file )

plotted_length = 0
max_plotted_length = 3000

for traj in trajectories[::-1] :

	if is_acceptable( traj,  min_length = 5, min_displacement = 10 ) :

		if plotted_length < max_plotted_length : # plot some trajectories
			step = 1
			i_max = max_plotted_length - plotted_length
			ax_phys.plot( traj.x[:i_max], traj.y[:i_max], alpha = .5 )
			plotted_length += len(traj.x)

		index = arange( len( traj.x ) )

####################
#
# adjust plot
#
####################

ax_phys.axis('scaled')
ax_phys.set_xticks([])
ax_phys.set_yticks([])
ax_phys.axis('off')
ax_phys.set_title( 'Run ' + file_to_letter[experiment] )

fig.savefig('trajectories.pdf')

show()