SPARTA (23 Dec 2017)
# advect particles via VSS collisional flow on a uniform grid
# particles reflect off global box boundaries

variable            x index 10
variable            y index 10
variable            z index 10

variable            lx equal $x*1.0e-5
variable            lx equal 128*1.0e-5
variable            ly equal $y*1.0e-5
variable            ly equal 80*1.0e-5
variable            lz equal $z*1.0e-5
variable            lz equal 80*1.0e-5

variable            n equal 10*$x*$y*$z
variable            n equal 10*128*$y*$z
variable            n equal 10*128*80*$z
variable            n equal 10*128*80*80

seed	    	    12345
dimension   	    3
global              gridcut 1.0e-5

boundary	    rr rr rr

create_box  	    0 ${lx} 0 ${ly} 0 ${lz}
create_box  	    0 0.00128 0 ${ly} 0 ${lz}
create_box  	    0 0.00128 0 0.0008 0 ${lz}
create_box  	    0 0.00128 0 0.0008 0 0.0008
Created orthogonal box = (0 0 0) to (0.00128 0.0008 0.0008)
create_grid 	    $x $y $z
create_grid 	    128 $y $z
create_grid 	    128 80 $z
create_grid 	    128 80 80
WARNING: Could not acquire nearby ghost cells b/c grid partition is not clumped (../grid.cpp:381)
Created 819200 child grid cells
  parent cells = 1
  CPU time = 0.0751324 secs
  create/ghost percent = 6.5853 93.4147

balance_grid        rcb part
Balance grid migrated 817791 cells
  CPU time = 0.528547 secs
  reassign/sort/migrate/ghost percent = 69.0234 0.022737 25.3367 5.61714

species		    ar.species Ar
mixture		    air Ar vstream 0.0 0.0 0.0 temp 273.15

global              nrho 7.07043E22
global              fnum 7.07043E6

collide		    vss air ar.vss

create_particles    air n $n
create_particles    air n 8192000
Created 8192000 particles
  CPU time = 0.0133918 secs

stats		    100
compute             temp temp
stats_style	    step cpu np nattempt ncoll c_temp

# first equilibrate with large timestep to unsort particles
# then benchmark with normal timestep

timestep 	    7.00E-8
run                 30
Memory usage per proc in Mbytes:
  particles (ave,min,max) = 1.6875 1.6875 1.6875
  grid      (ave,min,max) = 1.51388 1.51388 1.51388
  surf      (ave,min,max) = 0 0 0
  total     (ave,min,max) = 3.20138 3.20138 3.20138
Step CPU Np Natt Ncoll c_temp 
       0            0  8192000        0        0    273.03674 
      30   0.42253228  8192000  8219131  5787583    273.03674 
Loop time of 0.422642 on 576 procs for 30 steps with 8192000 particles

Particle moves    = 245760000 (246M)
Cells touched     = 1221122326 (1.22B)
Particle comms    = 73858883 (73.9M)
Boundary collides = 10742484 (10.7M)
Boundary exits    = 0 (0K)
SurfColl checks   = 0 (0K)
SurfColl occurs   = 0 (0K)
Surf reactions    = 0 (0K)
Collide attempts  = 237950823 (238M)
Collide occurs    = 172762622 (173M)
Reactions         = 0 (0K)
Particles stuck   = 0

Particle-moves/CPUsec/proc: 1.00952e+06
Particle-moves/step: 8.192e+06
Cell-touches/particle/step: 4.96876
Particle comm iterations/step: 3.73333
Particle fraction communicated: 0.300533
Particle fraction colliding with boundary: 0.0437113
Particle fraction exiting boundary: 0
Surface-checks/particle/step: 0
Surface-collisions/particle/step: 0
Surf-reactions/particle/step: 0
Collision-attempts/particle/step: 0.968224
Collisions/particle/step: 0.702973
Reactions/particle/step: 0

Move  time (%) = 0.154519 (36.5603)
Coll  time (%) = 0.116941 (27.669)
Sort  time (%) = 0.0246202 (5.82531)
Comm  time (%) = 0.125622 (29.723)
Modfy time (%) = 0 (0)
Outpt time (%) = 0.000790965 (0.187148)
Other time (%) = 0.000149033 (0.0352622)

Particles: 14222.2 ave 14603 max 13885 min
Histogram: 4 25 60 110 135 118 77 34 10 3
Cells:      1422.22 ave 1423 max 1422 min
Histogram: 448 0 0 0 0 0 0 0 0 128
GhostCell: 1947.17 ave 2861 max 978 min
Histogram: 11 38 60 37 146 87 32 109 41 15
EmptyCell: 803.806 ave 1364 max 120 min
Histogram: 19 23 59 64 62 112 57 86 39 55
timestep 	    7.00E-9
run 		    $t
run 		    100
Memory usage per proc in Mbytes:
  particles (ave,min,max) = 1.6875 1.6875 1.6875
  grid      (ave,min,max) = 1.51388 1.51388 1.51388
  surf      (ave,min,max) = 0 0 0
  total     (ave,min,max) = 3.20138 3.20138 3.20138
Step CPU Np Natt Ncoll c_temp 
      30            0  8192000  8219131  5787583    273.03674 
     100   0.23838149  8192000   786012   577939    273.03674 
     130   0.34455036  8192000   796683   578748    273.03674 
Loop time of 0.344732 on 576 procs for 100 steps with 8192000 particles

Particle moves    = 819200000 (819M)
Cells touched     = 1142903283 (1.14B)
Particle comms    = 30210745 (30.2M)
Boundary collides = 3582116 (3.58M)
Boundary exits    = 0 (0K)
SurfColl checks   = 0 (0K)
SurfColl occurs   = 0 (0K)
Surf reactions    = 0 (0K)
Collide attempts  = 76747672 (76.7M)
Collide occurs    = 57484993 (57.5M)
Reactions         = 0 (0K)
Particles stuck   = 0

Particle-moves/CPUsec/proc: 4.12559e+06
Particle-moves/step: 8.192e+06
Cell-touches/particle/step: 1.39515
Particle comm iterations/step: 1
Particle fraction communicated: 0.0368784
Particle fraction colliding with boundary: 0.0043727
Particle fraction exiting boundary: 0
Surface-checks/particle/step: 0
Surface-collisions/particle/step: 0
Surf-reactions/particle/step: 0
Collision-attempts/particle/step: 0.0936861
Collisions/particle/step: 0.0701721
Reactions/particle/step: 0

Move  time (%) = 0.156579 (45.4206)
Coll  time (%) = 0.0645955 (18.7379)
Sort  time (%) = 0.0766265 (22.2278)
Comm  time (%) = 0.0450604 (13.0711)
Modfy time (%) = 0 (0)
Outpt time (%) = 0.0016936 (0.49128)
Other time (%) = 0.000176785 (0.0512819)

Particles: 14222.2 ave 14562 max 13836 min
Histogram: 6 10 35 74 110 138 112 59 26 6
Cells:      1422.22 ave 1423 max 1422 min
Histogram: 448 0 0 0 0 0 0 0 0 128
GhostCell: 1947.17 ave 2861 max 978 min
Histogram: 11 38 60 37 146 87 32 109 41 15
EmptyCell: 803.806 ave 1364 max 120 min
Histogram: 19 23 59 64 62 112 57 86 39 55