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[Karol Brzezinski <question698541@xxxxxxxxxxxxxxxxxxxxx>]

Question #698541 on Yade changed:
https://answers.launchpad.net/yade/+question/698541

    Status: Open => Answered

Karol Brzezinski proposed the following answer:
Hi Leonard,

sphere pack only stores information about sphere positions and radii
(try to read sp1[0]). So, in my opinion, you can skip the part where you
append sphere pecks to simulation and then you read this information
back from simulation. I guess that you wanted* to achieve something like
this:


######### SCRIPT 1
from yade import pack
O.periodic=True
#### define material, two materials are used for 2 type of particles
Mat1 = O.materials.append(FrictMat(young=2e6,poisson=0.3,frictionAngle=radians(30),label='mat1'))
Mat2 = O.materials.append(FrictMat(young=2e6,poisson=0.3,frictionAngle=radians(30),label='mat2'))
######## particles with Mat1
sp1=pack.SpherePack()
sp1.makeCloud((0,0,0),(5,5,5),rMean=.5,rRelFuzz=.5,periodic=True,num=5)
######## particles with Mat2
sp2=pack.SpherePack()
sp2.makeCloud((0,0,0),(5,5,5),rMean=.05,rRelFuzz=.0,periodic=True,num=5)
######## this is a good moment to add sphere packs to simulation
sp1.cellRepeat((1, 3, 1))
sp2.cellRepeat((1, 3, 1))
sp1.toSimulation(color=(0,0,1),material='mat1')
sp2.toSimulation(color=[1,0,0],material='mat2')

## print the material ids, I found that all the material ids are 1, but I expect to have two types of materials.
for i in O.bodies:
 print (i.material.id)
######## END OF SCRIPT 1

*I don't really think you wanted the above script. If you generate
spheres in separate sphere packs, they do not see each other and may
overlap. I think that better approach is to run makeCloud twice on one
sphere pack, and then split to the separate sphere packs based on some
condition (most likely radius size in your example). This approach do
not work with cellRepeat command. But I think that you may just want to
create longer cell at the beginning of the simulation.

######### SCRIPT 2
from yade import pack
O.periodic=True
#### define material, two materials are used for 2 type of particles
Mat1 = O.materials.append(FrictMat(young=2e6,poisson=0.3,frictionAngle=radians(30),label='mat1'))
Mat2 = O.materials.append(FrictMat(young=2e6,poisson=0.3,frictionAngle=radians(30),label='mat2'))
### prepare sphere pack
sp=pack.SpherePack()
sp.makeCloud((0,0,0),(5,15,5),rMean=.5,rRelFuzz=.5,periodic=True,num=15)# I changed dimensions of the cell. I increased number of spheres for better visualization.
sp.makeCloud((0,0,0),(5,15,5),rMean=.05,rRelFuzz=.0,periodic=True,num=500)# Now, spheres shouldn't overlap since they can see each other.
#### now split into two packs, eg. based on the radius 
sp1=pack.SpherePack()
sp2=pack.SpherePack()
sp1.isPeriodic = True
sp2.isPeriodic = True
sp1.cellSize = (5,15,5)
sp1.cellSize = (5,15,5)
for s in sp:
	pos = s[0]
	r = s[1]
	if r>0.05:
		sp1.add(pos,r)
	else:
		sp2.add(pos,r)
######## this is a good moment to add sphere packs to simulation

sp1.toSimulation(color=(0,0,1),material='mat1')
sp2.toSimulation(color=[1,0,0],material='mat2')

## print the material ids, I found that all the material ids are 1, but I expect to have two types of materials.
for i in O.bodies:
 print (i.material.id)
######### END OF SCRIPT 2

Last, but not leas solution. Still, makeCloud twice on one spherePack.
Add it to simulation, and just change properties of selected spheres.

######### SCRIPT 3
from yade import pack
O.periodic=True
#### define material, two materials are used for 2 type of particles
Mat1 = O.materials.append(FrictMat(young=2e6,poisson=0.3,frictionAngle=radians(30),label='mat1'))
Mat2 = O.materials.append(FrictMat(young=2e6,poisson=0.3,frictionAngle=radians(30),label='mat2'))
### prepare sphere pack
sp=pack.SpherePack()
sp.makeCloud((0,0,0),(5,5,5),rMean=.5,rRelFuzz=.5,periodic=True,num=15)# @Karol: I increased number of spheres for better visualization.
sp.makeCloud((0,0,0),(5,5,5),rMean=.05,rRelFuzz=.0,periodic=True,num=500)# Now, spheres shouldn't overlap since they can see each other.
######## this is a good moment to add sphere packs to simulation
sp.cellRepeat((1, 3, 1))
sp.toSimulation(color=[1,0,0],material='mat1')

# now change the material of spheres based of the shere size
for b in O.bodies:
	if isinstance(b.shape, Sphere):#just making sure I am dealing with spheres before asking for radius
		if b.shape.radius <= 0.05:
			b.material = O.materials[Mat2]
			b.shape.color=[0,0,1] # change color for better visualization.

## print the material ids, I found that all the material ids are 1, but I expect to have two types of materials.
for i in O.bodies:
 print (i.material.id)
######### END OF SCRIPT 3

Cheers, 
Karol

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