Question about i.phys.normalForce()

Hi,

The error says the i.phys you want to access is "NoneType", probably it does not exist. Did you run at least one iteration (with O.step(), or O.run() ) ?
It is necessary for the interactions to be detected and exist.

Jérôme

Hi Henry,

in your example, it is really veeeeery strange, that
F0 = i.phys.normalForce[0]
works without ok, but
F1 = i.phys.normalForce[1]
gives this error..

So a little investigation :-)
- is this the first error you get during the running of the program?
- could you please create a minimal working example (deleting all
unnecessary code not related to your problem) and send it to us?

cheers
Jan

2014-04-15 10:31 GMT+02:00 Henry <email address hidden>:

> New question #247021 on Yade:
> https://answers.launchpad.net/yade/+question/247021
>
> Dear all,
> I want to generate a sample with the average contact force lies in a
> range [Permit_Min_Force,Permit_Max_Force] throught the following code.
> However when I obtain the interaction force through "i.phys.normalForce()",
> some errors are listed during the calculations.
> Is the interaciton not update, after I change the radius of the
> spheres? if so, how can I update the incteraction properties during the
> simulaiton?
>
> Errors:
>
> File "PackInPolygon_new.py", line 229, in Cal_Interface
> F1=i.phys.normalForce[1]
> AttributeError: 'NoneType' object has no attribute 'normalForce'
>
>
> The codes:
>
> Permit_Min_Force=500.0
> Permit_Max_Force=2.0*Permit_Min_Force
>
> def Cal_Interface():
> Rf=0.0
> Contact_Num=0
> aa=dict(O.energy.items())
> for i in O.interactions:
> if not i.isReal:continue
> F0=i.phys.normalForce[0]
> F1=i.phys.normalForce[1]
> F2=i.phys.normalForce[1]
> f=sqrt(F0*F0+F1*F1+F2*F2)
> # print('f:', f)
> Rf=Rf+f
> Contact_Num=Contact_Num+1
> return Rf, Contact_Num
>
> while 1:
> Sign=0
> O.run(1000)
> (Rf, Contact_Num)=Cal_Interface()
> print("Rf=", Rf,"Contact_Num=", Contact_Num)
> if Contact_Num>0:
> Rf=Rf/Contact_Num
> else:
> Rf=0.0
> if Rf>Permit_Min_Force:
> Mult=0.99
> if Rf<Permit_Max_Force:
> Mult=1.01
> if Rf>Permit_Min_Force and Rf<Permit_Max_Force:
> Sign=1
> Mult=1
> for o in O.bodies:
> if isinstance(o.shape,Sphere):
> R=o.shape.radius
> o.shape.radius=R*Mult
> print("Contact_Num=", Contact_Num,"Sign=", Sign)
> if Sign==1:
> break
>
> Thanks a lot!
>
> Henry
>
>
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Hi Jan,
    Many thanks for your help, and the script of my file, please check it. Thanks a lot!

# -*- coding: utf-8

from yade import utils,qt,export
from yade import plot
from yade.pack import *

mesh='Circle5cm' #name of gts mesh
surface=gts.read(open(mesh+'.gts'))

execfile('GenSPheresInSurface.py') #import a series of sphere in "surface"

O.materials.append(FrictMat(young=5.0e10,poisson=.1,density=3000000,frictionAngle=.0))

for b in O.bodies:

    if isinstance(b.shape,Sphere):
        b.state.blockedDOFs='zXY' # blocked movement along Z
        b.state.vel[1]=0.0
    if isinstance(b.shape,Clump):
        Clump_Num=Clump_Num+1
        b.state.blockedDOFs='yXYZ' # blocked movement along Y
        b.state.vel[1]=0.0

O.bodies.append(pack.gtsSurface2Facets(surface,color=(0.8,0.8,0.8),wire=True))

O.engines=[
 ForceResetter(),
 InsertionSortCollider([Bo1_Sphere_Aabb(),Bo1_Facet_Aabb()],label='collider'),
 InteractionLoop(
  [Ig2_Sphere_Sphere_ScGeom(),Ig2_Facet_Sphere_ScGeom()],
  [Ip2_FrictMat_FrictMat_FrictPhys()],
  [Law2_ScGeom_FrictPhys_CundallStrack()],
 ),
 NewtonIntegrator(damping=0.9,gravity=(0,0.0,0.0)),
]

O.dt=1.0*utils.PWaveTimeStep()
O.timingEnabled=True;
O.run(2000)

Permit_Min_Force=500.0
Permit_Max_Force=2.0*Permit_Min_Force

def Cal_Interface():
    Rf=0.0
    Contact_Num=0
    for i in O.interactions:
            if not i.isReal:continue
            F0=i.phys.normalForce[0]
            F1=i.phys.normalForce[1]
            f=sqrt(F0*F0+F1*F1)#i.phys.normalForce().norm()
            Rf=Rf+f
            Contact_Num=Contact_Num+1
    return Rf, Contact_Num

def Gen_S():
    while 1:
        Sign=0
        O.run(1000)
        (Rf, Contact_Num)=Cal_Interface()
        print("Rf=", Rf,"Contact_Num=", Contact_Num)
        if Contact_Num>0:
            Rf=Rf/Contact_Num
        else:
            Rf=0.0
        if Rf>Permit_Min_Force:
            Mult=0.99
        if Rf<Permit_Max_Force:
            Mult=1.01
        if Rf>Permit_Min_Force and Rf<Permit_Max_Force:
            Sign=1
            Mult=1
        for o in O.bodies:
            if isinstance(o.shape,Sphere):
                R=o.shape.radius
                o.shape.radius=R*Mult
        print("Contact_Num=", Contact_Num,"Sign=", Sign)
        if Sign==1:
            break

Gen_S()

export.text(mesh+'.spheres')
print("Export the Spheres model successfuly!")

Henry

However when I added the "Gen_S()" function in the Enginers as follows, its ok.

O.engines = O.engines+[PyRunner(command='Gen_S()',iterPeriod=10000,label='checker_Por')]

Thanks a lot!

I am really confused now :-) so your code is working now?
Jan

2014-04-15 11:56 GMT+02:00 Henry <email address hidden>:

> Question #247021 on Yade changed:
> https://answers.launchpad.net/yade/+question/247021
>
> Henry posted a new comment:
> However when I added the "Gen_S()" function in the Enginers as follows,
> its ok.
>
> O.engines =
>
> O.engines+[PyRunner(command='Gen_S()',iterPeriod=10000,label='checker_Por')]
>
> Thanks a lot!
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-users
> Post to : <email address hidden>
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> More help : https://help.launchpad.net/ListHelp
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The code is not working.
And I can't find the reason now.
Thanks!
Henry

ok :-)
to test your script, I will also need files:
- Circle5cm.gts
- GenSPheresInSurface.py

could you please place it somewhere on the internet so I can download them?
thanks
Jan

2014-04-17 2:51 GMT+02:00 Henry <email address hidden>:

> Question #247021 on Yade changed:
> https://answers.launchpad.net/yade/+question/247021
>
> Henry posted a new comment:
> The code is not working.
> And I can't find the reason now.
> Thanks!
> Henry
>
> --
> You received this question notification because you are a member of
> yade-users, which is an answer contact for Yade.
>
> _______________________________________________
> Mailing list: https://launchpad.net/~yade-users
> Post to : <email address hidden>
> Unsubscribe : https://launchpad.net/~yade-users
> More help : https://help.launchpad.net/ListHelp
>