Generation of sphere packing using CohFrictMat model

Hello all,

I want to make a simulation of slope using FEMxDEM code. Dr. Guo Ning proposed a good example for the generation of 2D friction packing. I also see Ning also using the FEMxDEM method for cohesive materials. I want to change the prepare.py and set cohesion and rolling friction using CohFrictMat model. The problem is divided into two sstep, firstly a sphere packing without friction and cohesion is compressed to the hydrostatic stress. Then I want to add rolling friction and cohesion to the model. But it does not work, I really appriciate if anyone can give me some advice. Tho code is as following:

from yade import pack

#O.materials.append(FrictMat(young=6.e8,poisson=.8,frictionAngle=.0))
materialId=O.materials.append(CohFrictMat(young=15e6,poisson=0.4,frictionAngle=0,normalCohesion=1e6,shearCohesion=1e6,momentRotationLaw=True,etaRoll=0.1,label='spheres'))

sp = pack.SpherePack()
size = .24
sp.makeCloud(minCorner=(0,0,.05),maxCorner=(size,size,.05),rMean=.005,rRelFuzz=.4,num=400,periodic=True,seed=1)
sp.toSimulation(material='spheres')
O.cell.hSize = Matrix3(size,0,0, 0,size,0, 0,0,.1)
print len(O.bodies)
for p in O.bodies:
   p.state.blockedDOFs = 'zXY'
   p.state.mass = 2650 * 0.1 * pi * p.shape.radius**2 # 0.1 = thickness of cylindrical particle
   inertia = 0.5 * p.state.mass * p.shape.radius**2
   p.state.inertia = (.5*inertia,.5*inertia,inertia)

O.dt = utils.PWaveTimeStep()
print O.dt

O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb()]),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom6D()],
  [Ip2_CohFrictMat_CohFrictMat_CohFrictPhys()],
  [Law2_ScGeom6D_CohFrictPhys_CohesionMoment(always_use_moment_law=False)]
 ),
 PeriTriaxController(
  dynCell=True,
  goal=(-1.e5,-1.e5,0),
  stressMask=3,
  relStressTol=.001,
  maxUnbalanced=.001,
  maxStrainRate=(.5,.5,.0),
  doneHook='term()',
  label='biax'
 ),
 GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.5),
 NewtonIntegrator(damping=.2)
]

def term():
   O.engines = O.engines[:3]+O.engines[4:]
   print getStress()
   print O.cell.hSize
   setContactFriction(radians(30))
   O.cell.trsf=Matrix3.Identity
   O.cell.velGrad=Matrix3.Zero
   for p in O.bodies:
      p.state.vel = Vector3.Zero
      p.state.angVel = Vector3.Zero
      p.state.refPos = p.state.pos
      p.state.refOri = p.state.ori
   O.save('0.yade.gz')
   O.pause()

# servo the stress to the hydrostress state
O.run();O.wait()
#This will reload the autosaved compacted sample
O.reload()
# I want to change the model with rolling friction and Cohesion
O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb()]),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom6D()],
  [Ip2_CohFrictMat_CohFrictMat_CohFrictPhys()],
  [Law2_ScGeom6D_CohFrictPhys_CohesionMoment(always_use_moment_law=False)]
 ),
 GlobalStiffnessTimeStepper(active=1,timeStepUpdateInterval=100,timestepSafetyCoefficient=0.5),
 NewtonIntegrator(damping=.2)
]
# Add rolling friction and Cohesion to the model
O.engines[2].lawDispatcher.functors[1].always_use_moment_law = True
O.engines[2].physDispatcher.functors[1].setCohesionNow = True
O.step();O.wait();O.save('1.yade.gz')

Thanks in advance!!!
The error information is as follows：
Traceback (most recent call last):
  File "/usr/bin/yadedaily", line 182, in runScript
    execfile(script,globals())
  File "prepareRVECoh.py", line 75, in <module>
    O.engines[2].lawDispatcher.functors[1].always_use_moment_law = True
IndexError: list index out of range
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