from espressomd import System, lb, lbboundaries, shapes

sys = System()
sys.box_l = [64, 64, 64]
sys.time_step = 0.1
sys.cell_system.skin = 0.4

lb = lb.LBFluid(agrid=1.0, dens=1.0, visc=1.0, fric=1.0, tau=0.1)
sys.actors.add(lb)

v = [0, 0, 0.01]  #the boundary slip
walls = [None] * 4

wall_shape = shapes.Wall(normal=[1,0,0], dist=1)
walls[0] = lbboundaries.LBBoundary(shape=wall_shape, velocity=v)

wall_shape = shapes.Wall(normal=[-1,0,0], dist=-63)
walls[1] = lbboundaries.LBBoundary(shape=wall_shape, velocity=v)

wall_shape = shapes.Wall(normal=[0,1,0], dist=1)
walls[2] = lbboundaries.LBBoundary(shape=wall_shape, velocity=v)

wall_shape = shapes.Wall(normal=[0,-1,0], dist=-63)
walls[3] = lbboundaries.LBBoundary(shape=wall_shape, velocity=v)

for wall in walls:
    sys.lbboundaries.add(wall)

sphere_shape = shapes.Sphere(radius=5.5, center=[33,33,33], direction=1)
sphere = lbboundaries.LBBoundary(shape=sphere_shape)
sys.lbboundaries.add(sphere)

cycle = 0
while (cycle < 4000):
    print(str(cycle ))
    print("fluid velocity near right wall: " + str(lb[62,30,30].velocity))

    sys.integrator.run(10)
    cycle = cycle + 10

print(sphere.get_force())