I got a memory error when conducted an impact simulation

Hi,
I plan to conduct an impact simulation, i.e. a rigid ball impact on a cuboid assembly of particles at a certain speed. But, I got an error as follows:
huihuangxia@huihuangxia-Presario-CQ42-Notebook-PC:~$ cd Desktop/impact
huihuangxia@huihuangxia-Presario-CQ42-Notebook-PC:~/Desktop/impact$ mpirun -np 2 `which esysparticle` impact.py
CSubLatticeControler::initMPI()
slave started at local/global rank 0 / 1
Traceback (most recent call last):
  File "impact.py", line 55, in <module>
    pList = geoRandomBlock_particles
MemoryError

My code is here, please help me to tackle this problem.

#import essential modules to simulation
from esys.lsm import *
from esys.lsm.util import *
from esys.lsm.geometry import *
#initialise a simulation and neighbour search algorithm
sim = LsmMpi(numWorkerProcesses=1, mpiDimList=[1,1,1])
sim.initNeighbourSearch(
    particleType="NRotSphere",
 gridSpacing=2.5,
 verletDist=0.5
)
#set total timestep and its increment
sim.setNumTimeSteps(10000)
sim.setTimeStepSize(0.1)
#specify the spatial domain
domain = BoundingBox(Vec3(0,0,0),Vec3(0.1,0.1,0.5))
sim.setSpatialDomain(domain)
#cerate checkpointer to save simulation data
sim.createCheckPointer(
    CheckPointPrms(
     fileNamePrefix="impact_",
  beginTimeStep=0,
  endTimeStep=10000,
  timeStepIncr=100
 )
)
#add the impactor to this simulation
impactor=NRotSphere(id=0,posn=Vec3(0.05,0.05,1.0),radius=0.05,mass=5.0)
impactor.setLinearVelocity(Vec3(0,0,-1))
sim.createParticle(impactor)
#create a random spherical partcile package
geoRandomBlock = RandomBoxPacker (
 minRadius = 0.005,
 maxRadius = 0.01,
 cubicPackRadius = 2.2000,
 maxInsertFails = 5000,
 bBox = BoundingBox(
  Vec3(0,0,0),
  Vec3(0.1,0.1,0.5)
 ),
 circDimList = [False, False, False],
 tolerance = 1.0000e-05
)
geoRandomBlock.generate()
geoRandomBlock_particles = geoRandomBlock.getSimpleSphereCollection()
#add the particles to the simulation object:
sim.createParticles(geoRandomBlock_particles)
#bond particles together with bondTag = 1:
sim.createConnections(
 ConnectionFinder(
 maxDist = 0.0005,
 bondTag = 1,
 pList = geoRandomBlock_particles
 )
)
#create rotational elastic-brittle bonds between particles:
pp_bonds = sim.createInteractionGroup (
BrittleBeamPrms(
name="pp_bonds",
youngsModulus=100000.0,
poissonsRatio=0.25,
cohesion=100.0,
tanAngle=1.0,
tag=1
)
)
#initialise frictional interactions for unbonded particles:
sim.createInteractionGroup (
FrictionPrms(
name="friction",
youngsModulus=100000.0,
poissonsRatio=0.25,
dynamicMu=0.4,
staticMu=0.6
)
)
#create an exclusion between bonded and frictional interactions:
sim.createExclusion (
interactionName1 = "pp_bonds",
interactionName2 = "friction"
)
#initialise gravity in the domain
sim.createInteractionGroup(
 GravityPrms(name="gravity",acceleration=Vec3(0,0,-9.81))
)
#create a wall at the bottom of this model
sim.createWall(
 name="bottom_wall",
 posn=Vec3(0.1,0,0),
 normal=Vec3(0,0,1)
)
#specify elastic repulsion from th ebottom wall
sim.createInteractionGroup (
 NRotElasticWallPrms (
 name = "bottom_wall_repel",
 wallName = "bottom_wall",
 normalK = 100000.0
 )
)
#add translational viscous damping:
sim.createInteractionGroup (
 LinDampingPrms(
 name="damping1",
 viscosity=0.002,
 maxIterations=50
 )
)
#add rotational viscous damping:
sim.createInteractionGroup (
 RotDampingPrms(
 name="damping2",
 viscosity=0.002,
 maxIterations=50
 )
)
#execute the simulation
sim.run()