The initial arrangement of particles in SPH (solved by two pictures)

Therefore, the corresponding code is （ Change from Tai Chi k-ye Of pbf2d.py）

def init():
    init_pos = ti.Vector([0.2,0.3,0.2])
    cube_size = 0.4
    spacing = 0.02
    num_per_row = (int) (cube_size // spacing)
    num_per_floor = num_per_row * num_per_row
    for i in range(num_particles):
        floor = i // (num_per_floor) 
        row = (i % num_per_floor) // num_per_row
        col = (i % num_per_floor) % num_per_row
        positions[i] = ti.Vector([row*spacing, floor*spacing, col*spacing]) + init_pos