fix multisphere/break integration, how to work?

Hi

I am trying a mulisphere break case.

In the LIGGGHTS Tutorials-public "multisphere_stone_restitution" example in.multisphere file, I add

"fix m6 all property/atom fz scalar yes no no 0.02"
before integrator, and change integrator to be

"fix integr all multisphere/break trigger_threshold 0.1 trigger_timeStep 0 trigger_fixName m6"

After type ./lmp_fedora -echo both < in.multisphere2, I get the ERROR of

run 20000 upto
ERROR: Could not locate a fix/property storing value(s) for m6 as requested by multisphere/break. (../modify_liggghts.cpp:385)
(../modify_liggghts.cpp:385)

Does anyone help to tell me how to figure it out?

Thanks!

Below are Error information and input file. Thanks for helping!

#######################################################
... ...
#region and insertion
region bc cylinder z 0.0 0.0 0.25 0.1 0.4 units box

fix ins all insert/pack seed 32452843 distributiontemplate pdd1 vel constant 0. 0. -1. insert_every once overlapcheck yes region bc ntry_mc 10000 volumefraction_region 0.0004

fix m6 all property/atom fz scalar yes no no 0.02

#integrator for multisphere rigid bodies
#fix integr all multisphere
fix integr all multisphere/break trigger_threshold 0.1 trigger_timeStep 0 trigger_fixName m6
iarg:3
FixMultisphereBreak will use trigger_threshold: 0.1
iarg:5
FixMultisphereBreak will use trigger_timeStep: 0
iarg:7
FixMultisphereBreak will use fixPropertyAtom with name 'm6' (length: 2) as trigger.
...initialized FixMultisphereBreak with trigger_fixName: m6!

#output settings, include total thermal energy
compute 1 all erotate/sphere
fix ts all check/timestep/gran 1000 0.1 0.1
thermo_style custom step atoms ke c_1 f_ts[1] f_ts[2] vol
thermo 1000
thermo_modify lost ignore norm no

#insert the first particles so that dump is not empty
dump dmp all custom 200 post/dump*.multi id type mol x y z vx vy vz fx fy fz omegax omegay omegaz radius

#insert particles
run 20000 upto
ERROR: Could not locate a fix/property storing value(s) for m6 as requested by multisphere/break. (../modify_liggghts.cpp:385)
(../modify_liggghts.cpp:385)

#######################################################

#%%%%%%% in.multisphere2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
#put in the folder of LIGGGHTS-PUBLIC/examples/LIGGGHTS/Tutorials_public/multisphere_stone_restitution/
#Multisphere

atom_style sphere
atom_modify map array sort 0 0
boundary m m m
newton off

communicate single vel yes

#PUBLIC version only supports serial execution
processors 1 1 1

units si

region reg block -0.3 0.3 -0.3 0.3 0. 0.5 units box
create_box 1 reg

neighbor 0.004 bin
neigh_modify delay 0

#Material properties required for new pair styles

fix m1 all property/global youngsModulus peratomtype 1.e7
fix m2 all property/global poissonsRatio peratomtype 0.45
fix m3 all property/global coefficientRestitution peratomtypepair 1 0.3
fix m4 all property/global coefficientFriction peratomtypepair 1 0.5
fix m5 all property/global characteristicVelocity scalar 2.

#New pair style
pair_style gran model hertz tangential history #Hertzian without cohesion
pair_coeff * *

timestep 0.00001

fix gravi all gravity 9.81 vector 0.0 0.0 -1.0

fix zwalls all wall/gran model hertz tangential history primitive type 1 zplane 0.0

#distributions for insertion
fix pts1 all particletemplate/multisphere 15485863 atom_type 1 density constant 2500 nspheres 2 ntry 1000000 spheres file data/stone1.test scale 0.001 type 1
fix pdd1 all particledistribution/discrete 15485867 1 pts1 1.0

#region and insertion
region bc cylinder z 0.0 0.0 0.25 0.1 0.4 units box

fix ins all insert/pack seed 32452843 distributiontemplate pdd1 vel constant 0. 0. -1. &
insert_every once overlapcheck yes region bc ntry_mc 10000 volumefraction_region 0.0004

fix m6 all property/atom fz scalar yes no no 0.02 #I CHANGE HERE
#fix m6 all property/atom characteristicVelocity scalar yes no no 0.02 #I CHANGE HERE

#integrator for multisphere rigid bodies
#fix integr all multisphere
fix integr all multisphere/break trigger_threshold 0.1 trigger_timeStep 0 trigger_fixName m6 #I CHANGE HERE

#output settings, include total thermal energy
compute 1 all erotate/sphere
fix ts all check/timestep/gran 1000 0.1 0.1
thermo_style custom step atoms ke c_1 f_ts[1] f_ts[2] vol
thermo 1000
thermo_modify lost ignore norm no

#insert the first particles so that dump is not empty
dump dmp all custom 200 post/dump*.multi id type mol x y z vx vy vz fx fy fz omegax omegay omegaz radius

#insert particles
run 20000 upto

#%%%%%%% in.multisphere2 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%