imposible to reach specific porosity

Hello,
I cannot reach the target porosity. The script based on periodical triaxial test tutorial example. After isotropic stage finished, the simulation stopped as well so that the porosity condition could not be satisfied. Maybe I am wrong with O.run command. Could you please help me?

from __future__ import print_function

import time
import datetime
import os

from yade import pack, plot, export
import numpy as np

#FIXED PARAMETERS

poisson=0.2
R=1e-3
rate=1e-2
dimcell = 0.03
density= 1e9
young=1e9
frictionAngle=radians(30)
targetPorosity=0.43

#SETTINGS
O.periodic = True
O.cell.hSize = Matrix3(dimcell , 0, 0, 0, dimcell , 0, 0, 0, dimcell )

sp = pack.SpherePack()
sp.makeCloud((0, 0, 0), (dimcell, dimcell, dimcell), rMean=R, rRelFuzz=.1, periodic=True)

pp = O.materials.append(CohFrictMat(
 young=young,
 poisson=poisson,
 frictionAngle=frictionAngle,
 density=density,
 isCohesive=False,
 momentRotationLaw=True,
 etaRoll=.1,label='spheres'
 ))

sp.toSimulation(material='spheres')

O.engines = [
        ForceResetter(
               ),
        InsertionSortCollider([Bo1_Sphere_Aabb()]),
        InteractionLoop([Ig2_Sphere_Sphere_ScGeom6D()], [Ip2_CohFrictMat_CohFrictMat_CohFrictPhys()],[Law2_ScGeom6D_CohFrictPhys_CohesionMoment(useIncrementalForm=True,always_use_moment_law=True)]),
 PeriTriaxController(goal=(-1e4,-1e4,-1e4),
    relStressTol=1e-3,
    stressMask=7,
    maxStrainRate=(rate, rate, rate),
    dynCell=True,
    maxUnbalanced=.1,
    label='triax',
    doneHook = 'triaxDone()'
    ),
 NewtonIntegrator(damping=.2),
        PyRunner(command='addPlotData()', iterPeriod=500),
 ]

O.dt = .5 * PWaveTimeStep()
print('time step',O.dt)

def triaxDone():
 frictionAngle=radians(30)
 while utils.porosity>targetPorosity:
  frictionAngle = 0.7*frictionAngle
  setContactFriction(frictionAngle)
  print (frictionAngle," porosity:",utils.porosity())
                O.run(500000,1)

def addPlotData():
 plot.addData(
         i=O.iter,
         Ezz=log(O.cell.trsf[2,2]),
  Eyy=log(O.cell.trsf[1,1]),
  Exx=log(O.cell.trsf[0,0]),
  szz=utils.getStress()[2,2],
  syy=utils.getStress()[1,1],
  sxx=utils.getStress()[0,0],
         u=utils.porosity()
 )

# define what to plot
plot.plots = {
        'i ': ('sxx', 'syy', 'szz'),
        ' i': ('Exx', 'Eyy', 'Ezz'),
 ' i ':('u')
        # energy plot

}
# show the plot
plot.plot()