def test_tribend(self):
self.system.actors.clear()
# two triangles with bending interaction
# move nodes, should relax back
system = self.system
system.virtual_sites = VirtualSitesInertialessTracers()
system.part.clear()
# Add four particles
system.part.add(id=0, pos=[5, 5, 5], virtual=1)
system.part.add(id=1, pos=[5, 5, 6], virtual=1)
system.part.add(id=2, pos=[5, 6, 6], virtual=1)
system.part.add(id=3, pos=[5, 6, 5], virtual=1)
# Add first triel, weak modulus
from espressomd.interactions import IBM_Triel
tri1 = IBM_Triel(
ind1=0, ind2=1, ind3=2, elasticLaw="Skalak", k1=0.1, k2=0, maxDist=2.4)
system.bonded_inter.add(tri1)
system.part[0].add_bond((tri1, 1, 2))
# Add second triel
tri2 = IBM_Triel(
ind1=0, ind2=2, ind3=3, elasticLaw="Skalak", k1=10, k2=0, maxDist=2.4)
system.bonded_inter.add(tri2)
system.part[0].add_bond((tri2, 2, 3))
# Add bending
from espressomd.interactions import IBM_Tribend
tribend = IBM_Tribend(
ind1=0, ind2=1, ind3=2, ind4=3, kb=1, refShape="Initial")
system.bonded_inter.add(tribend)
system.part[0].add_bond((tribend, 1, 2, 3))
# twist
system.part[1].pos = [5.2, 5, 6]
self.reset_lb()
# Perform integration
last_angle = self.compute_angle()
for i in range(6):
system.integrator.run(430)
angle = self.compute_angle()
self.assertLess(angle, last_angle)
last_angle = angle
self.assertLess(angle, 0.03)
def AddBending(system, kb):
# currently only works for ONE SINGLE soft object
# angles
from espressomd.interactions import IBM_Tribend
with open("tables/softAngles", "r") as fp:
numAngles = int(fp.readline())
print "Found " + str(numAngles) + " angles"
# actual add
for i in range(0, numAngles):
line = str.split(fp.readline())
id1 = int(line[0])
id2 = int(line[1])
id3 = int(line[2])
id4 = int(line[3])
tribend = IBM_Tribend(ind1=id1,
ind2=id2,
ind3=id3,
ind4=id4,
kb=kb,
refShape="initial")
system.bonded_inter.add(tribend)
system.part[id1].add_bond((tribend, id2, id3, id4))
def test_tribend(self):
# two triangles with bending interaction
# move nodes, should relax back
system = self.system
system.virtual_sites = VirtualSitesInertialessTracers()
self.lbf.set_params(ext_force_density=(0.0, 0., 0.))
self.stop_fluid()
system.part.clear()
## Add four particles
system.part.add(id=0, pos=[5, 5, 5], virtual=1)
system.part.add(id=1, pos=[5, 5, 6], virtual=1)
system.part.add(id=2, pos=[5, 6, 6], virtual=1)
system.part.add(id=3, pos=[5, 6, 5], virtual=1)
## Add first triel, weak modulus
from espressomd.interactions import IBM_Triel
tri1 = IBM_Triel(ind1=0,
ind2=1,
ind3=2,
elasticLaw="Skalak",
k1=0.1,
k2=0,
maxDist=2.4)
system.bonded_inter.add(tri1)
system.part[0].add_bond((tri1, 1, 2))
## Add second triel
tri2 = IBM_Triel(ind1=0,
ind2=2,
ind3=3,
elasticLaw="Skalak",
k1=10,
k2=0,
maxDist=2.4)
system.bonded_inter.add(tri2)
system.part[0].add_bond((tri2, 2, 3))
## Add bending
from espressomd.interactions import IBM_Tribend
tribend = IBM_Tribend(ind1=0,
ind2=1,
ind3=2,
ind4=3,
kb=1,
refShape="Initial")
system.bonded_inter.add(tribend)
system.part[0].add_bond((tribend, 1, 2, 3))
## output before
print("Angle before twisting: " + str(self.compute_angle()))
## twist
system.part[1].pos = [5.2, 5, 6]
## output after
print("Angle after twisting: " + str(self.compute_angle()))
## Perform integrat[ion
last_angle = self.compute_angle()
for i in range(8):
system.integrator.run(500)
angle = self.compute_angle()
print("Angle after relaxation: ", angle)
self.assertLess(angle, last_angle)
last_angle = angle
self.assertLess(angle, 0.03)