I am trying to create a simulation within yade with different sphere radius to fall by gravity into a container

import random
import math
from yade import geom, pack, plot

# create cylindrical body with radius 6 cm and height 6.05 cm
cylinder = yade.geom.facetCylinder((0,0,0), radius=0.06, height=0.065, segmentsNumber=80, wallMask=6)
O.bodies.append(cylinder)

# create empty sphere packing
sp = pack.SpherePack()

# specify the radii and ratios
radii_ratios = [(0.000075, 0.04), (0.0006, 0.06), (0.00236, 0.05), (0.00475, 0.35), (0.0095, 0.20), (0.0125, 0.30)]

# generate spheres with specified radii and ratios
for r, ratio in radii_ratios:
   num_spheres = int(ratio * 1000)
   sp.makeCloud((-0.055,-0.055,0.20), (0.055,0.055,0.09), rMean=r, rRelFuzz=0, num=num_spheres)

# add the sphere pack to the simulation
sp.toSimulation()

O.engines = [ForceResetter(),
  InsertionSortCollider([Bo1_Sphere_Aabb(), Bo1_Facet_Aabb()]),
  InteractionLoop(
          # handle sphere+sphere and facet+sphere collisions
          [Ig2_Sphere_Sphere_ScGeom(), Ig2_Facet_Sphere_ScGeom()],
          [Ip2_FrictMat_FrictMat_FrictPhys()],
          [Law2_ScGeom_FrictPhys_CundallStrack()]
  ),
  NewtonIntegrator(gravity=(0,0,-9.81), damping=0.4),
]
O.dt = 2 * PWaveTimeStep()

# run the simulation for 1000 steps
O.run(1000)

# calculate the volume of the packing
volume_packing = 0
num_spheres = 0
for b in O.bodies:
  if isinstance(b.shape, yade.wrapper.Sphere):
      volume_packing += 4/3 * math.pi * b.shape.radius**3
      num_spheres += 1

# calculate the volume of the cylinder
volume_cylinder = math.pi * 0.06**2 * 0.0605

# calculate the porosity and porosity percentage
porosity = (volume_cylinder - volume_packing) / volume_cylinder
porosity_percent = porosity * 100

print("Number of spheres:", "{:.2f}".format(num_spheres))
print("V Packing:", "{:.2f}".format(volume_packing))
print("V Cylinder:", "{:.2f}".format(volume_cylinder))
print("Porosity:", "{:.2f}".format(porosity))
print("Porosity:", "{:.2f}%".format(porosity_percent))

I was able to complete the simulation but the simulation doesn't fully packed and V packing and V cylinder are calculated as 0
Is there any guide on how to make the sphere pack better in the container?
Why does the calculation is calculated as 0?