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Message #26239
[Question #698825]: Yade-batch is being indeterministic
New question #698825 on Yade:
https://answers.launchpad.net/yade/+question/698825
Hello,
I am simulating the interaction between a brush (modelled using gridConnections) and a rotating box (pfacet clump). I noticed some inconsistencies in the batch simulations and I tried a batch simulation in which the only parameter that was changed was the ID. The outputs of each simulation in the batch were different. From what I understand according to [1], there YADE will be indeterministic when it a single simulation is run in parallel multiple times. However, I understood that YADE-batch has each simulation running using one thread/code by default. So why are all the results different? Please find my code below. Please note I am using the json module in python to write and read the data. You may have to install it using pip install json
Kind regards,
Rohit K. John
[1] https://yade-dem.org/doc/formulation.html#result-indeterminism
# -------------------------------------------------------------------------------------------------------------------------------------------- parameters.table
ID
1
2
3
4
5
6
7
8
9
10
# -------------------------------------------------------------------------------------------------------------------------------------------- cube_LP.gts
14 36 24 GtsSurface GtsFace GtsEdge GtsVertex
0.03 0.03 0.03
0.03 0.03 -0.03
0.03 -0.03 0.03
0.03 -0.03 -0.03
-0.03 0.03 0.03
-0.03 0.03 -0.03
-0.03 -0.03 0.03
-0.03 -0.03 -0.03
0.03 0.0 0.0
0.0 0.03 0.0
-0.03 0.0 0.0
0.0 0.0 0.03
0.0 -0.03 0.0
0.0 0.0 -0.03
6 8
2 6
1 2
8 7
3 4
5 6
3 7
1 3
8 4
7 5
5 1
4 2
9 3
2 9
4 9
1 9
10 1
6 10
5 10
2 10
11 5
8 11
7 11
6 11
12 3
5 12
7 12
1 12
13 7
4 13
8 13
3 13
14 4
6 14
8 14
2 14
7 25 27
7 29 32
10 21 23
12 33 36
8 13 16
11 17 19
12 14 15
5 15 13
3 16 14
2 18 20
6 19 18
3 20 17
1 22 24
4 23 22
6 24 21
11 26 28
10 27 26
8 28 25
9 30 31
4 31 29
5 32 30
1 34 35
9 35 33
2 36 34
# --------------------------------------------------------------------------------------------------------------------------------------------python script
from yade.gridpfacet import *
from yade import plot
import sys
import json
from json import JSONEncoder
sys.path.append(".")
# ---------------------------------------------------------------------------------------------- input parameter
simulation_mode = "batch"
if simulation_mode == 'single':
ID = 14
# randomness = 0e-7
elif simulation_mode == 'batch':
readParamsFromTable(
ID = 14,
# randomness = 0e-7
)
from yade.params.table import *
# ---------------------------------------------------------------------------------------------- input parameter
# ----------------------------------------------------- target
target_young = 3.2e6
target_density = 1250
target_poisson = 0.48
target_friction = radians(44)
p_radius = 1e-3
# ---------------------------------------------------------------------------------------------------------------------------- Materials
target_int_mat = 'pfacet_int_mat'
target_ext_mat = 'pfacet_ext_mat'
O.materials.append(
FrictMat(
young = target_young,
poisson = target_poisson,
density = target_density,
label = target_ext_mat,
frictionAngle = target_friction,
)
)
O.materials.append(
CohFrictMat(
young = target_young,
poisson = target_poisson,
density = target_density,
label = target_int_mat,
frictionAngle = target_friction,
normalCohesion = 3e100,
shearCohesion = 3e100,
momentRotationLaw = True,
)
)
# ---------------------------------------------------------------------------------------------------------------------------- Engines
O.engines = [
ForceResetter(),
InsertionSortCollider([
Bo1_GridConnection_Aabb(),
Bo1_PFacet_Aabb(),
Bo1_Sphere_Aabb(),
]),
InteractionLoop(
[
Ig2_PFacet_PFacet_ScGeom(),
Ig2_GridConnection_GridConnection_GridCoGridCoGeom(),
Ig2_GridNode_GridNode_GridNodeGeom6D(),
Ig2_GridConnection_PFacet_ScGeom(),
Ig2_Sphere_PFacet_ScGridCoGeom(),
],
[
Ip2_FrictMat_FrictMat_FrictPhys(),
Ip2_CohFrictMat_CohFrictMat_CohFrictPhys(
setCohesionNow = True,
setCohesionOnNewContacts = False
),
],
[
Law2_GridCoGridCoGeom_FrictPhys_CundallStrack(),
Law2_ScGeom_FrictPhys_CundallStrack(),
Law2_ScGridCoGeom_FrictPhys_CundallStrack(),
Law2_ScGeom6D_CohFrictPhys_CohesionMoment(),
],
)
]
# ---------------------------------------------------------------------------------------------------------------------------- objects
# ---------------------------------------------------------------------- target
target_pos = [0.0, 0.0, 70e-3]
(
pnode,
pcyl,
pfacet
) = gtsPFacet(
'cube_LP.gts',
radius = p_radius,
shift = target_pos,
scale = 1,
wire = False,
fixed = False,
color = [0.1,0.5,0.1],
materialNodes = 'pfacet_int_mat',
material = 'pfacet_ext_mat',
)
target_ids = pnode + pcyl + pfacet
for i in pcyl:
O.bodies[i].state.mass = 1e-13 # or else the mass of the gridConnections will be added to clump
target_clump_ID = O.bodies.clump(target_ids)
O.bodies[target_clump_ID].state.blockedDOFs = "xyzYZ"
ang_vel = 50
O.bodies[target_clump_ID].state.angVel = [ang_vel, 0.0, 0.0]
# ---------------------------------------------------------------------- brush
n_rows = 5
n_cols = 11
n_segs = 11
dx = 2.4375e-3
dz = 2.4375e-3
bristle_tip_pos_y = 35.55e-3
bristle_tip_pos_z = 63.5e-3
brislte_len = 35e-3
dy = brislte_len / (n_segs - 1)
bristle_radius = 1e-3
nodeIds=[]
connectionIds=[]
for row_i in range(n_rows):
for col_i in range(n_cols):
brislte_seg_ids = []
for seg_i in range(n_segs):
pos = Vector3([
col_i * dx,
seg_i * dy + bristle_tip_pos_y,
row_i * dz + bristle_tip_pos_z,
])
brislte_seg_ids.append(
O.bodies.append(
gridNode(pos,
bristle_radius,
wire=False,
fixed=False,
material='pfacet_int_mat',
) ) )
nodeIds = nodeIds + brislte_seg_ids
O.bodies[nodeIds[-1]].state.blockedDOFs = "xyzXYZ"
for idx in range(len(brislte_seg_ids[1:])):
connectionIds.append(
O.bodies.append(
gridConnection(
brislte_seg_ids[idx], brislte_seg_ids[idx + 1],
bristle_radius,
material='pfacet_ext_mat'
) ) )
# ----------------------------------------------------------------------------------------------- Additional engines
O.engines += [
NewtonIntegrator(gravity = [0,0,0], damping = 0),
PyRunner(command = 'graph()', iterPeriod = 1000),
PyRunner(command = 'stopper()', iterPeriod = 200000)
]
# ---------------------------------------------------------------------- plotting
plot.plots = {'t':('wx')}
def graph():
w = O.bodies[target_clump_ID].state.angVel
plot.addData(
t = O.time,
wx = w[0]
)
plot.plot()
# ---------------------------------------------------------------------- VectorEncoder
class VectorEncoder(JSONEncoder):
"""
This is used to serialise the Vector3 class so that json.dump can write this class
"""
def default(self, o):
return list(o)
def stopper():
result_dict = {}
result_dict['data'] = plot.data
result_dict["ID"] = ID
file_json = 'Sim_result_ID_' + str(ID) + '.json'
with open(file_json, 'w') as f:
json.dump(result_dict, f, indent=4, cls=VectorEncoder)
O.pause()
# ----------------------------------------------------------------------------------------------- Sim controller
O.dt = 1e-6
if simulation_mode == 'batch':
O.run()
waitIfBatch()
else:
O.saveTmp()
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