1*97929ea7SJunchao Zhang 2*97929ea7SJunchao ZhangOn rank 0 of PETSC_COMM_WORLD, x = 0 1 2 3 4 3*97929ea7SJunchao ZhangOn rank 0 of PETSC_COMM_WORLD, y1 = 0 1 2 3 4 4*97929ea7SJunchao ZhangOn rank 0 of PETSC_COMM_WORLD, y2 = 5 6 7 8 9 5