# encoding: utf-8
# 2010 © Václav Šmilauer <eudoxos@arcig.cz>
'''
Various computations affected by the periodic boundary conditions.
'''
import unittest
import random,math
from minieigen import *
from woo import utils
import woo
from woo.core import *
from woo.dem import *
[docs]class TestPBC(unittest.TestCase):
# prefix test names with PBC:
[docs] def setUp(self):
woo.master.scene=S=Scene(fields=[DemField()])
S.periodic=True;
S.cell.setBox(2.5,2.5,3)
self.cellDist=Vector3i(0,0,10) # how many cells away we go
self.relDist=Vector3(0,.999999999999999999,0) # rel position of the 2nd ball within the cell
self.initVel=Vector3(0,0,5)
S.dem.par.add(Sphere.make((1,1,1),.5))
self.initPos=Vector3([S.dem.par[0].pos[i]+self.relDist[i]+self.cellDist[i]*S.cell.hSize0.col(i).norm() for i in (0,1,2)])
S.dem.par.add(utils.sphere(self.initPos,.5))
S.dem.par[1].vel=self.initVel
S.engines=[Leapfrog(reset=True)]
S.cell.nextGradV=Matrix3(0,0,0, 0,0,0, 0,0,-1)
S.cell.homoDeform='vel2'
S.dt=0 # do not change positions with dt=0 in NewtonIntegrator, but still update velocities from velGrad
[docs] def testVelGrad(self):
"PBC: velGrad changes hSize but not hSize0, accumulates in trsf (homoDeform='vel2')"
S=woo.master.scene
S.cell.homoDeform='vel2'
S.dt=1e-3
hSize,trsf=S.cell.hSize,Matrix3.Identity
hSize0=hSize
for i in range(0,10):
hSize+=S.dt*S.cell.gradV*hSize; trsf+=S.dt*S.cell.gradV*trsf
S.one();
#print hSize, S.cell.hSize
#print trsf, S.cell.trsf
for i in range(0,len(S.cell.hSize)):
self.assertAlmostEqual(hSize[i],S.cell.hSize[i])
self.assertAlmostEqual(trsf[i],S.cell.trsf[i])
# ?? should work
#self.assertAlmostEqual(hSize0[i],S.cell.hSize0[i])
[docs] def testTrsfChange(self):
'PBC: chaing trsf changes hSize0, but does not modify hSize'
S=woo.master.scene
S.dt=1e-2
S.one()
S.cell.trsf=Matrix3.Identity
for i in range(0,len(S.cell.hSize)):
self.assertAlmostEqual(S.cell.hSize0[i],S.cell.hSize[i])
[docs] def testDegenerate(self):
"PBC: degenerate cell raises exception"
S=woo.master.scene
self.assertRaises(RuntimeError,lambda: setattr(S.cell,'hSize',Matrix3(1,0,0, 0,0,0, 0,0,1)))
[docs] def testSetBox(self):
"PBC: setBox modifies hSize correctly"
S=woo.master.scene
S.cell.setBox(2.55,11,45)
self.assertTrue(S.cell.hSize==Matrix3(2.55,0,0, 0,11,0, 0,0,45));
[docs] def testHomotheticResizeVel(self):
"PBC: homothetic cell deformation adjusts particle velocity (homoDeform=='vel')"
S=woo.master.scene
S.dt=1e-5
S.cell.homoDeform='vel'
s1=S.dem.par[1]
#print 'init',self.initPos,self.initVel
#print 'before',s1.pos,s1.vel
S.one()
#print 'after',s1.pos,s1.vel
self.assertAlmostEqual(s1.vel[2],self.initVel[2]+self.initPos[2]*S.cell.gradV[2,2])
[docs] def testHomotheticResizePos(self):
"PBC: homothetic cell deformation adjusts particle position (homoDeform=='pos')"
S=woo.master.scene
S.cell.homoDeform='pos'
S.one()
s1=S.dem.par[1]
self.assertAlmostEqual(s1.vel[2],self.initVel[2])
self.assertAlmostEqual(s1.pos[2],self.initPos[2]+self.initPos[2]*S.cell.gradV[2,2]*S.dt)
[docs] def testL6GeomIncidentVelocity(self):
"PBC: L6Geom incident velocity (homoDeform=='gradV2')"
S=woo.master.scene
S.cell.homoDeform='gradV2'
S.one()
S.engines=[ForceResetter(),ContactLoop([Cg2_Sphere_Sphere_L6Geom()],[Cp2_FrictMat_FrictPhys()],[Law2_L6Geom_FrictPhys_IdealElPl(noBreak=True)]),Leapfrog(reset=True)]
i=utils.createContacts([0],[1])[0]
S.dt=1e-10; S.one() # tiny timestep, to not move the normal too much
self.assertAlmostEqual(self.initVel.norm(),i.geom.vel.norm())
[docs] def testL3GeomIncidentVelocity_homoPos(self):
"PBC: L6Geom incident velocity (homoDeform=='pos')"
S=woo.master.scene
S.cell.homoDeform='pos'; S.one()
S.engines=[ForceResetter(),ContactLoop([Cg2_Sphere_Sphere_L6Geom()],[Cp2_FrictMat_FrictPhys()],[Law2_L6Geom_FrictPhys_IdealElPl(noBreak=True)]),Leapfrog(reset=True)]
i=utils.createContacts([0],[1])[0]
S.dt=1e-10; S.one()
self.assertAlmostEqual(self.initVel.norm(),i.geom.vel.norm())
#self.assertAlmostEqual(self.relDist[1],1-i.geom.penetrationDepth)
[docs] def testKineticEnergy(self):
"PBC: Particle.getEk considers only fluctuation velocity, not the velocity gradient (homoDeform=='vel2')"
S=woo.master.scene
S.cell.homoDeform='vel2'
S.one() # updates velocity with homotheticCellResize
# ½(mv²+ωIω)
# #0 is still, no need to add it; #1 has zero angular velocity
# we must take self.initVel since S.dem.par[1].vel now contains the homothetic resize which utils.kineticEnergy is supposed to compensate back
Ek=.5*S.dem.par[1].mass*self.initVel.squaredNorm()
self.assertAlmostEqual(Ek,S.dem.par[1].getEk(trans=True,rot=False,scene=S))
[docs] def testKineticEnergy_homoPos(self):
"PBC: Particle.Ekt considers only fluctuation velocity, not the velocity gradient (homoDeform=='pos')"
S=woo.master.scene
S.cell.homoDeform='pos'; S.one()
self.assertAlmostEqual(.5*S.dem.par[1].mass*self.initVel.squaredNorm(),S.dem.par[1].Ekt)
[docs]class TestPBCCollisions(unittest.TestCase):
[docs] def setUp(self):
woo.master.scene=S=Scene(fields=[DemField()])
S.periodic=True
S.cell.setBox(1.,1.,1.)
S.engines=[InsertionSortCollider([Bo1_Sphere_Aabb()])]
#self.cellDist=Vector3i(0,0,10) # how many cells away we go
#self.relDist=Vector3(0,.999999999999999999,0) # rel position of the 2nd ball within the cell
#self.initVel=Vector3(0,0,5)
#S.dem.par.add(utils.sphere((1,1,1),.5))
#S.one()
#self.assertTrue(S.dem.con[0,1].cellDist==Vector3i(0,0,0))
[docs] @unittest.skipIf(woo.config.compiler[0]=='clang','THIS CRASHES WITH CLANG AND DEBUGGING, SKIPPING. SHOULD BE FIXED!!!')
def testCrossBoundarySort(self):
'PBC: InsertionSortCollider correctly sorts on the boundary (bug #... discovered by Bruno)'
rr=1e-6
S=woo.core.Scene(dt=1,
fields=[woo.dem.DemField(par=[woo.dem.Sphere.make((x+rr,0,0),rr) for x in (0,.5,.8)])],
engines=[woo.dem.Leapfrog(reset=True),woo.dem.InsertionSortCollider([woo.dem.Bo1_Sphere_Aabb()],verletDist=0,label='coll',paraPeri=False)]
)
S.periodic=True
S.cell.setBox(1,1,1)
S.one()
# check initial bound for #1
#print(S.lab.coll.dumpBounds()[0])
x0,sid,wrap,flags=S.lab.coll.dumpBounds()[0][2]
self.assertEqual(x0,.5)
self.assertEqual(sid,-1) # signed ID, neg. for lower bound
self.assertEqual(wrap,0)
# move by one step
s1=S.dem.par[1]
s1.vel=(.53,0,0)
S.one()
# check updated bound for #1
#print(S.lab.coll.dumpBounds()[0])
x0,sid,wrap,_=S.lab.coll.dumpBounds()[0][2]
self.assertAlmostEqual(x0,.03,delta=1e-5) # moved by this amount
self.assertEqual(sid,-1)
self.assertEqual(wrap,1) # moved by one period already
# check bounds are sorted correctly
bb=[float(b[0]) for b in S.lab.coll.dumpBounds()[0]]
bs=sorted(bb)
self.assertEqual(bb,bs)