def __init__(self):
    self.n_particles = 0
    self.n_solid_particles = 0
    self.x = []
    self.actuator_id = []
    self.particle_type = []
    self.offset_x = 0
    self.offset_y = 0
    self.offset_z = 0
    self.num_actuators = 0
def __init__(self):
    self.n_particles = 0
    self.n_solid_particles = 0
    self.x = []
    self.actuator_id = []
    self.particle_type = []
    self.offset_x = 0
    self.offset_y = 0
    self.offset_z = 0
    self.num_actuators = 0