(1) Begin
(2) Each processor sends the update data of particles in the border to other processors, then
receives the update data of particles from other processors and copies them in Neighbor_Copy;
(3) Calculate the diffusion probability and diffusion direction of the particle j in Local_Store;
(4) Execute the diffusion of particles, update , mark particles which enter other Neighbor_Copy;
(5) If all particles in Local_Store are finished scanning, go to (6); Otherwise, go to (3);
(6) Communicate with other processor to update the data of particles in Neighbor_Copy;
(7) End
Algorithm 4: The diffusion simulation algorithm of dust particles.