def test_melt_using_groups(self):
""" 3d Lennard-Jones melt with two atom types """
L = PyLammps()
L.units('lj')
L.atom_style('atomic')
L.lattice('fcc', 0.8442) # NOTE: lattice command is different in LJ units
L.region('whole block', 0.0, 10.0, 0, 10, 0, 10)
L.create_box(2, 'whole')
L.region('upper block', 4.9, 10.1, 'EDGE EDGE EDGE EDGE')
L.region('lower block', 0.0, 4.9, 'EDGE EDGE EDGE EDGE')
# fill box with atoms according to lattice positions
L.create_atoms(1, 'region upper')
L.create_atoms(2, 'region lower')
L.mass(1, 1.0)
L.mass(2, 2.0)
L.group('gu', 'type', 1)
L.group('gl', 'type', 2)
L.velocity('gu', 'create 2.0 12345 mom no rot no')
L.velocity('gl', 'create 4.0 54321 mom no rot no')
L.timestep(0.002)
L.pair_style('lj/cut', 2.5)
L.pair_coeff('* *', 1.0, 1.0, 2.5)
L.fix('f1 all nve')
#L.dump('d1 all image 500 snap-03.*.jpg type type')
L.thermo(50)
L.run(500)
def test_default_settings(self):
L = PyLammps()
# verify default settings
self.assertEqual(L.system.natoms, 0)
self.assertEqual(L.system.ntypes, 0)
self.assertEqual(L.system.style, 'none')
self.assertEqual(L.system.units, 'lj')
self.assertEqual(L.system.kspace_style, 'none')
self.assertEqual(L.system.atom_style, 'atomic')
self.assertEqual(L.system.atom_map, 'none')
# now explicitly set them and check if nothing changed
L.units('lj')
L.boundary("p p p")
L.lattice("none 1.0")
L.atom_style("atomic")
self.assertEqual(L.system.natoms, 0)
self.assertEqual(L.system.ntypes, 0)
self.assertEqual(L.system.style, 'none')
self.assertEqual(L.system.units, 'lj')
self.assertEqual(L.system.kspace_style, 'none')
self.assertEqual(L.system.atom_style, 'atomic')
self.assertEqual(L.system.atom_map, 'none')
def test_real_units(self):
L = PyLammps()
L.units('real') # angstrom, kcal/mol, femtoseconds
L.atom_style('atomic')
L.boundary('p p p')
L.lattice('none', 1.0)
# create simulation cell
L.region('r1 block', -15.0, 15.0, -15.0, 15.0, -15.0, 15.0)
L.create_box(1, 'r1')
# argon
L.mass(1, 39.948002)
L.pair_style('lj/cut', 8.5)
L.pair_coeff(1, 1, 0.2379, 3.405)
L.timestep(10.0)
L.create_atoms(1, 'single', -1.0, 0.0, 0.0)
L.create_atoms(1, 'single', 1.0, 0.0, 0.0)
L.velocity('all create', 250.0, 54321, 'mom no rot no')
L.minimize(1.0e-10, 1.0e-10, 100, 1000)
L.reset_timestep(0)
L.thermo(100)
L.fix('f1 all nve')
L.run(1000)
def test_melt(self):
""" 3d Lennard-Jones melt """
L = PyLammps()
L.units('lj')
L.atom_style('atomic')
L.lattice('fcc', 0.8442) # NOTE: lattice command is different in LJ units
# 0.8442 is density fraction
L.region('r1 block', 0, 10, 0, 10, 0, 10)
L.create_box(1, 'r1')
# fill box with atoms according to lattice positions
L.create_atoms(1, 'box')
L.mass(1, 1.0)
L.velocity('all create', 3.0, 87287, 'mom no')
L.timestep(0.002)
L.pair_style('lj/cut', 2.5)
L.pair_coeff(1, 1, 1.0, 1.0, 2.5)
L.fix('f1 all nve')
L.dump('d1 all image 500 snap-01.*.jpg type type')
L.thermo(50)
L.run(500)
self.assertTrue(os.path.exists('snap-01.0.jpg'))
self.assertTrue(os.path.exists('snap-01.500.jpg'))
os.remove('snap-01.0.jpg')
os.remove('snap-01.500.jpg')
def setUp(self):
"""create 3d rocksalt-like structure"""
L = PyLammps()
L.units('real') # kcal/mol, Angstrom, picoseconds
L.atom_style('charge') # atomic + charge
# lattice for Na+ ions and box
L.lattice('fcc', 6.0, 'origin', 0.0, 0.0, 0.0)
L.region('r1', 'block', -3, 3,-3, 3,-3, 3)
L.create_box(2, 'r1')
# fill box with Na+ ions according to lattice positions
L.create_atoms(1, 'box')
# new lattice for Cl- ions shifted by half box diagonal
L.lattice('fcc', 6.0, 'origin', 0.5, 0.5, 0.5)
L.create_atoms(2, 'box')
L.mass(1, 22.989770)
L.mass(2, 35.453)
L.set('type', 1, 'charge', 1.0)
L.set('type', 2, 'charge', -1.0)
L.group('na type', 1)
L.group('cl type', 2)
L.velocity('all create', 800.0, 12345, 'mom no rot no')
L.timestep(0.001)
self.L = L
def test_create_box(self):
L = PyLammps()
L.units('real')
L.lattice('fcc', 3.5)
L.region("a block", 0, 1, 0, 1, 0, 1)
L.create_box(1, 'a')
self.assertEqual(L.system.dimensions, 3)
self.assertEqual(L.system.orthogonal_box, [3.5, 3.5, 3.5])
self.assertEqual(L.system.boundaries, 'p,p p,p p,p')
self.assertEqual(L.system.xlo, 0.0)
self.assertEqual(L.system.ylo, 0.0)
self.assertEqual(L.system.zlo, 0.0)
self.assertEqual(L.system.xhi, 3.5)
self.assertEqual(L.system.yhi, 3.5)
self.assertEqual(L.system.zhi, 3.5)
def data(i):
lmp1 = lammps()
polymer = PyLammps(ptr=lmp1)
x = 60
y = 30
z = 30
t = 1
polymer.units("lj")
polymer.dimension(3)
polymer.atom_style("bond")
polymer.bond_style("harmonic")
polymer.pair_style("lj/cut", 3)
polymer.read_data("data.polymer")
polymer.region("void cylinder x", 15, 15, 2, 29, 31)
polymer.pair_coeff(1, 2, 2.5, 3)
polymer.pair_coeff(1, 3, 2.5, 1.12)
polymer.pair_coeff(2, 3, 2.5, 1.12)
polymer.velocity("all create", t, 97287)
polymer.group("polymer type", 1, 2)
polymer.group("first type", 1)
polymer.region("box block", 0, x, 0, y, 0, z)
polymer.region("spherein sphere", 29, 15, 15, 2)
polymer.region("boxin block", 27, 29, 13, 17, 13, 17)
polymer.region("hemiin intersect", 2, "boxin spherein")
x0 = polymer.atoms[0].position[0]
y0 = polymer.atoms[0].position[1]
z0 = polymer.atoms[0].position[2]
r = lambda x0, y0, z0: np.sqrt((x0 - 29)**2 + (y0 - 15)**2 + (z0 - 15)**2)
fx = lambda x0, y0, z0: 5 * (x0 - 29) / r(x0, y0, z0)
fy = lambda x0, y0, z0: 5 * (y0 - 15) / r(x0, y0, z0)
fz = lambda x0, y0, z0: 5 * (z0 - 15) / r(x0, y0, z0)
polymer.fix(1, "polymer nve")
polymer.fix(2, "polymer langevin", t, t, 1.5,
np.random.randint(2, high=200000))
polymer.fix(3, "polymer spring tether", 10, i, "NULL NULL", 0)
polymer.timestep(0.01)
polymer.compute("com polymer com")
polymer.variable("ftotal equal fcm(polymer,x)")
polymer.variable("c equal c_com[1]")
polymer.thermo_style("custom v_ftotal v_c")
polymer.thermo(1)
polymer.run(500000)
l = polymer.runs[0][0][1][20000:] + [i]
u = [np.mean(polymer.runs[0][0][0][20000:]), i]
np.savetxt("trial%dmean.txt" % i, u)
np.savetxt("trial%dall.txt" % i, l)
return u
def setUp(self):
L = PyLammps()
L.units('lj')
L.atom_style('atomic')
L.boundary('p p p')
L.atom_modify("map array")
L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0)
L.create_box(1, 'r1')
L.mass(1, 1.0)
L.create_atoms(1, 'single', -1.0, 0.0, 0.0)
L.create_atoms(1, 'single', 1.0, 0.0, 0.0)
L.pair_style('lj/cut', 5.0)
L.pair_coeff(1, 1, 1.0, 1.0)
L.run(0)
self.L = L
#!/usr/bin/env python3
from lammps import PyLammps, lammps
import numpy as np
import sys
l = lammps()
lmp = PyLammps(ptr=l)
lmp.units("lj")
lmp.atom_style("atomic")
lmp.lattice("fcc", 0.8442)
lmp.region("box", "block", 0, 4, 0, 4, 0, 4)
lmp.create_box(1, "box")
lmp.create_atoms(1, "box")
lmp.mass(1, 1.0)
lmp.velocity("all", "create", 10, 87287)
lmp.pair_style("lj/cut", 2.5)
lmp.pair_coeff(1, 1, 1.0, 1.0, 2.5)
lmp.neighbor(0.3, "bin")
lmp.neigh_modify("delay", 0, "every", 20, "check no")
lmp.fix("1 all nve")
a = l.extract_fix("2",2,2)
print(a.contents)
#nlocal = l.extract_global("nlocal",0)
#print(nlocal)
#lmp.fix("2 all addforce 1.0 0.0 0.0")
comm=mpi_comm,
verbose=args.verbose)
else:
py_lmp = PyLammps(cmdargs=['-echo', 'both'], comm=mpi_comm)
py_lmp.log('"' + log_path + '"')
rod_params = rods.Rod_params()
if mpi_rank == 0:
rod_params.from_file(args.cfg_file)
rod_params = mpi_comm.bcast(rod_params, root=0)
# CREATE BASE OBJECTS
model = rods.Rod_model(rod_params)
simulation = rods.Simulation(py_lmp, model, run_args.temp, seed, output_folder)
py_lmp.units("lj")
py_lmp.dimension(3)
py_lmp.boundary("p p p")
py_lmp.lattice("sc", 1 / (run_args.cell_size**3))
py_lmp.region("box", "block", -run_args.num_cells / 2, run_args.num_cells / 2,
-run_args.num_cells / 2, run_args.num_cells / 2,
-run_args.num_cells / 2, run_args.num_cells / 2)
simulation.setup("box")
simulation.create_rods(box=None)
# ROD DYNAMICS
py_lmp.fix("thermostat", "all", "langevin", run_args.temp, run_args.temp,
run_args.damp, seed) #, "zero yes")
simulation.set_rod_dynamics("nve", opt=["mol", model.rod_states[0]])
class RealUnitsLatticeBoxTests(unittest.TestCase):
def setUp(self):
self.L = PyLammps()
self.L.units('real') # default, use reduced units
self.L.atom_style('atomic') # default, point particles with mass and type
self.L.boundary('p p p') # default, periodic boundaries in 3-d
self.L.processors('* * *') # default, automatic domain decomposition
self.L.newton('on') # default, use newton's 3rd law for ghost particles
def assertAlmostEqualList(self, a_list, b_list):
for a, b in zip(a_list, b_list):
self.assertAlmostEqual(a, b, places=3)
def test_real_none_box(self):
self.L.lattice('none', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units box')
self.L.create_box(1, 'r1')
self.assertEqual(self.L.system.orthogonal_box, [10, 10, 10])
self.assertEqual(self.L.system.xlo, -5.0)
self.assertEqual(self.L.system.ylo, -5.0)
self.assertEqual(self.L.system.zlo, -5.0)
self.assertEqual(self.L.system.xhi, 5.0)
self.assertEqual(self.L.system.yhi, 5.0)
self.assertEqual(self.L.system.zhi, 5.0)
def test_real_sc_box(self):
self.L.lattice('sc', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units box')
self.L.create_box(1, 'r1')
self.assertEqual(self.L.system.orthogonal_box, [10, 10, 10])
self.assertEqual(self.L.system.xlo, -5.0)
self.assertEqual(self.L.system.ylo, -5.0)
self.assertEqual(self.L.system.zlo, -5.0)
self.assertEqual(self.L.system.xhi, 5.0)
self.assertEqual(self.L.system.yhi, 5.0)
self.assertEqual(self.L.system.zhi, 5.0)
def test_real_fcc_box(self):
self.L.lattice('fcc', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units box')
self.L.create_box(1, 'r1')
self.assertEqual(self.L.system.orthogonal_box, [10, 10, 10])
self.assertEqual(self.L.system.xlo, -5.0)
self.assertEqual(self.L.system.ylo, -5.0)
self.assertEqual(self.L.system.zlo, -5.0)
self.assertEqual(self.L.system.xhi, 5.0)
self.assertEqual(self.L.system.yhi, 5.0)
self.assertEqual(self.L.system.zhi, 5.0)
def test_real_bcc_box(self):
self.L.lattice('bcc', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units box')
self.L.create_box(1, 'r1')
self.assertEqual(self.L.system.orthogonal_box, [10, 10, 10])
self.assertEqual(self.L.system.xlo, -5.0)
self.assertEqual(self.L.system.ylo, -5.0)
self.assertEqual(self.L.system.zlo, -5.0)
self.assertEqual(self.L.system.xhi, 5.0)
self.assertEqual(self.L.system.yhi, 5.0)
self.assertEqual(self.L.system.zhi, 5.0)
def test_real_none_lattice(self):
self.L.lattice('none', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units lattice')
self.L.create_box(1, 'r1')
self.assertEqual(self.L.system.orthogonal_box, [10, 10, 10])
self.assertEqual(self.L.system.xlo, -5.0)
self.assertEqual(self.L.system.ylo, -5.0)
self.assertEqual(self.L.system.zlo, -5.0)
self.assertEqual(self.L.system.xhi, 5.0)
self.assertEqual(self.L.system.yhi, 5.0)
self.assertEqual(self.L.system.zhi, 5.0)
def test_real_sc_lattice(self):
self.L.lattice('sc', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units lattice')
self.L.create_box(1, 'r1')
self.assertEqual(self.L.system.orthogonal_box, [10, 10, 10])
self.assertAlmostEqual(self.L.system.xlo, -5.0)
self.assertAlmostEqual(self.L.system.ylo, -5.0)
self.assertAlmostEqual(self.L.system.zlo, -5.0)
self.assertAlmostEqual(self.L.system.xhi, 5.0)
self.assertAlmostEqual(self.L.system.yhi, 5.0)
self.assertAlmostEqual(self.L.system.zhi, 5.0)
def test_real_fcc_lattice(self):
self.L.lattice('fcc', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units lattice')
self.L.create_box(1, 'r1')
lattice_spacing = 1.0
self.assertAlmostEqualList(self.L.system.orthogonal_box, [10*lattice_spacing, 10*lattice_spacing, 10*lattice_spacing])
self.assertAlmostEqual(self.L.system.xlo, -5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.ylo, -5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.zlo, -5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.xhi, 5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.yhi, 5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.zhi, 5.0 * lattice_spacing, places=3)
def test_real_bcc_lattice(self):
self.L.lattice('bcc', 1.0)
self.L.region('r1 block', -5.0, 5.0, -5.0, 5.0, -5.0, 5.0, 'units lattice')
self.L.create_box(1, 'r1')
lattice_spacing = 1.0
self.assertAlmostEqualList(self.L.system.orthogonal_box, [10*lattice_spacing, 10*lattice_spacing, 10*lattice_spacing])
self.assertAlmostEqual(self.L.system.xlo, -5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.ylo, -5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.zlo, -5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.xhi, 5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.yhi, 5.0 * lattice_spacing, places=3)
self.assertAlmostEqual(self.L.system.zhi, 5.0 * lattice_spacing, places=3)
def test_change_system(self):
L = PyLammps()
L.units('real')
L.atom_style('charge')
self.assertEqual(L.system.units, 'real')
self.assertEqual(L.system.atom_style, 'charge')
membrane = Membrane(run_args.mem_sigma, run_args.mem_wc, run_args.mem_eps,
run_args.mem_Nx, run_args.mem_Ny, 0.0,
model.rod_length / 2, 5.0)
# ===== LAMMPS setup ====================================================================
if mpi_rank == 0:
py_lmp = PyLammps(cmdargs=['-echo', 'both'],
comm=mpi_comm,
verbose=args.verbose)
else:
py_lmp = PyLammps(cmdargs=['-echo', 'both'], comm=mpi_comm)
py_lmp.log('"' + log_path + '"')
simulation = rods.Simulation(py_lmp, model, run_args.temp, seed, output_folder)
py_lmp.units('lj')
py_lmp.dimension(3)
py_lmp.boundary('p p f')
py_lmp.region('box', 'block', membrane.xmin, membrane.xmax, membrane.ymin,
membrane.ymax, 0.0, run_args.Lz)
simulation.setup('box',
type_offset=max(membrane.bead_types),
extra_pair_styles=[('cosine/squared', model.global_cutoff)],
bond_offset=membrane.bond_type,
extra_bond_styles=['fene'],
opt=['angle/types', 1, 'extra/angle/per/atom', 1])
py_lmp.angle_style('harmonic')
zwalls_fix = 'zwalls'
py_lmp.fix(zwalls_fix, 'all', 'wall/lj126', 'zlo EDGE', 1.0, model.rod_radius,
class PythonPyLammps(unittest.TestCase):
def setUp(self):
machine = None
if 'LAMMPS_MACHINE_NAME' in os.environ:
machine = os.environ['LAMMPS_MACHINE_NAME']
self.pylmp = PyLammps(
name=machine,
cmdargs=['-nocite', '-log', 'none', '-echo', 'screen'])
self.pylmp.units("lj")
self.pylmp.atom_style("atomic")
self.pylmp.atom_modify("map array")
if 'LAMMPS_CMAKE_CACHE' in os.environ:
self.cmake_cache = {}
with open(os.environ['LAMMPS_CMAKE_CACHE'], 'r') as f:
for line in f:
line = line.strip()
if not line or line.startswith('#') or line.startswith(
'//'):
continue
parts = line.split('=')
key, value_type = parts[0].split(':')
if len(parts) > 1:
value = parts[1]
if value_type == "BOOL":
value = (value.upper() == "ON")
else:
value = None
self.cmake_cache[key] = value
def tearDown(self):
self.pylmp.close()
del self.pylmp
def test_version(self):
self.assertGreaterEqual(self.pylmp.version(), 20200824)
def test_create_atoms(self):
self.pylmp.region("box block", 0, 2, 0, 2, 0, 2)
self.pylmp.create_box(1, "box")
x = [1.0, 1.0, 1.0, 1.0, 1.0, 1.5]
types = [1, 1]
self.assertEqual(
self.pylmp.lmp.create_atoms(2, id=None, type=types, x=x), 2)
self.assertEqual(self.pylmp.system.natoms, 2)
self.assertEqual(len(self.pylmp.atoms), 2)
numpy.testing.assert_array_equal(self.pylmp.atoms[0].position,
tuple(x[0:3]))
numpy.testing.assert_array_equal(self.pylmp.atoms[1].position,
tuple(x[3:6]))
self.assertEqual(self.pylmp.last_run, None)
def test_write_script(self):
outfile = 'in.test_write_script'
self.pylmp.write_script(outfile)
self.assertTrue(os.path.exists(outfile))
os.remove(outfile)
def test_runs(self):
self.pylmp.lattice("fcc", 0.8442),
self.pylmp.region("box block", 0, 4, 0, 4, 0, 4)
self.pylmp.create_box(1, "box")
self.pylmp.create_atoms(1, "box")
self.pylmp.mass(1, 1.0)
self.pylmp.velocity("all create", 1.44, 87287, "loop geom")
self.pylmp.pair_style("lj/cut", 2.5)
self.pylmp.pair_coeff(1, 1, 1.0, 1.0, 2.5)
self.pylmp.neighbor(0.3, "bin")
self.pylmp.neigh_modify("delay 0 every 20 check no")
self.pylmp.fix("1 all nve")
self.pylmp.variable("fx atom fx")
self.pylmp.run(10)
self.assertEqual(len(self.pylmp.runs), 1)
self.assertEqual(self.pylmp.last_run, self.pylmp.runs[0])
self.assertEqual(len(self.pylmp.last_run.thermo.Step), 2)
self.assertEqual(len(self.pylmp.last_run.thermo.Temp), 2)
self.assertEqual(len(self.pylmp.last_run.thermo.E_pair), 2)
self.assertEqual(len(self.pylmp.last_run.thermo.E_mol), 2)
self.assertEqual(len(self.pylmp.last_run.thermo.TotEng), 2)
self.assertEqual(len(self.pylmp.last_run.thermo.Press), 2)
def test_info_queries(self):
self.pylmp.lattice("fcc", 0.8442),
self.pylmp.region("box block", 0, 4, 0, 4, 0, 4)
self.pylmp.create_box(1, "box")
self.pylmp.variable("a equal 10.0")
self.pylmp.variable("b string value")
self.assertEqual(self.pylmp.variables['a'].value, 10.0)
self.assertEqual(self.pylmp.variables['b'].value, 'value')
self.assertEqual(len(self.pylmp.variables), 2)
self.assertEqual(self.pylmp.system.units, 'lj')
self.assertEqual(self.pylmp.system.atom_style, 'atomic')
self.assertEqual(self.pylmp.system.ntypes, 1)
self.assertEqual(self.pylmp.system.natoms, 0)
self.assertEqual(self.pylmp.communication.comm_style, 'brick')
self.assertEqual(self.pylmp.communication.comm_layout, 'uniform')
self.assertEqual(self.pylmp.communication.nprocs, 1)
self.assertEqual(len(self.pylmp.computes), 3)
self.assertEqual(self.pylmp.computes[0]['name'], 'thermo_temp')
self.assertEqual(self.pylmp.computes[0]['style'], 'temp')
self.assertEqual(self.pylmp.computes[0]['group'], 'all')
self.assertEqual(self.pylmp.computes[1]['name'], 'thermo_press')
self.assertEqual(self.pylmp.computes[1]['style'], 'pressure')
self.assertEqual(self.pylmp.computes[1]['group'], 'all')
self.assertEqual(self.pylmp.computes[2]['name'], 'thermo_pe')
self.assertEqual(self.pylmp.computes[2]['style'], 'pe')
self.assertEqual(self.pylmp.computes[2]['group'], 'all')
self.assertEqual(len(self.pylmp.dumps), 0)
self.pylmp.fix('one', 'all', 'nve')
self.assertEqual(len(self.pylmp.fixes), 1)
self.assertEqual(self.pylmp.fixes[0]['name'], 'one')
self.assertEqual(self.pylmp.fixes[0]['style'], 'nve')
self.assertEqual(self.pylmp.fixes[0]['group'], 'all')
self.pylmp.group('none', 'empty')
self.assertEqual(len(self.pylmp.groups), 2)
def test_use_data_file(self):
L = PyLammps()
L.units('real') # angstrom, kcal/mol, femtoseconds
L.atom_style('atomic')
L.boundary('p p p')
L.lattice('none', 1.0)
# create simulation cell
L.region('r1 block', -15.0, 15.0, -15.0, 15.0, -15.0, 15.0)
L.create_box(1, 'r1')
# argon
L.mass(1, 39.948002)
L.pair_style('lj/cut', 8.5)
L.pair_coeff(1, 1, 0.2379, 3.405)
L.timestep(10.0)
L.create_atoms(1, 'single', -1.0, 0.0, 0.0)
L.create_atoms(1, 'single', 1.0, 0.0, 0.0)
L.velocity('all create', 250.0, 54321, 'mom no rot no')
L.minimize(1.0e-10, 1.0e-10, 100, 1000)
L.reset_timestep(0)
L.thermo(100)
L.fix('f1 all nve')
L.run(1000)
L.write_restart('run.restart')
L.write_data('run.data')
L2 = PyLammps()
L2.units('real') # angstrom, kcal/mol, femtoseconds
L2.atom_style('atomic')
L2.boundary('p p p')
L2.pair_style('lj/cut', 8.5)
L2.read_data('run.data')
L2.timestep(10.0)
L2.thermo(100)
L2.fix('f1 all nve')
L2.run(1000)
# reset status. forget all settings. delete system
L2.clear()
L2.read_restart('run.restart')
L2.thermo(100)
L2.fix('f1 all nve')
L2.run(1000)
os.remove('run.restart')
os.remove('run.data')
self.assertEqual(L.system, L2.system)
savealldisplacements = False # save a full list of all displacements after each experiment
# time spans for scattering simulation in ps:
initequalt = 1 # initial equilibration time between velocity reset and new scattering event
dcheckafterscatteringt = 0.4 # time between scattering event and displacement check
equilibrationt = 0.5 # time for equilibration
# continue from existing geometry?
continueprevsim = False
#reset geometry after every run?
resetgeom = False
selectfromNIST = True
# MD PARAMETERS:
L.units("metal")
L.atom_style("atomic")
L.atom_modify("map array")
latticeconst = 4.08
dispthresh = (4.08 + 3.52) / 2 / math.sqrt(2) * 0.90
NNthresh = (4.08 + 3.52) / 2 / math.sqrt(2) * 1.2
L.timestep(0.0005) # time-step in ps (metal units)
dsub = 10
density = 2000
Amass = 12.011 * 1.660538E-27
nPartsub = int(round(Lsub * Lsub * dsub * 1e-30 * density / Amass))
print(nPartsub)
def elastic():
""" Compute elastic constant tensor for a crystal
In order to calculate the elastic constants correctly, care must be taken to specify
the correct units (units). It is also important to verify that the minimization of energy
w.r.t atom positions in the deformed cell is fully converged.
One indication of this is that the elastic constants are insensitive
to the choice of the variable ${up}. Another is to check
the final max and two-norm forces reported in the log file. If you know
that minimization is not required, you can set maxiter = 0.0 """
parser = ArgumentParser(
description=
'A python script to compute elastic properties of bulk materials')
parser.add_argument("input_data_file",
help="The full path & name of the lammps data file.")
parser.add_argument(
"kim_model",
help="the KIM ID of the interatomic model archived in OpenKIM")
parser.add_argument(
"elements",
nargs='+',
default=['Au'],
help=
"a list of N chemical species, which defines a mapping between atom types in LAMMPS to the available species in the OpenKIM model"
)
parser.add_argument(
"--min_style",
default="cg",
help="which algorithm will be used for minimization from lammps")
parser.add_argument("--minimize",
type=float,
nargs=4,
default=[1.0e-4, 1.0e-6, 100, 1000],
help="minimization parameters")
parser.add_argument("--up",
type=float,
default=1.0e-6,
help="the deformation magnitude (in strain units)")
args = parser.parse_args()
L = PyLammps()
L.units("metal")
# Define the finite deformation size.
#Try several values to verify that results do not depend on it.
L.variable("up equal {}".format(args.up))
# Define the amount of random jiggle for atoms. It prevents atoms from staying on saddle points
atomjiggle = 1.0e-5
# metal units, elastic constants in GPa
cfac = 1.0e-4
# Define minimization parameters
L.variable("dmax equal 1.0e-2")
L.boundary("p", "p",
"p") # periodic boundary conditions in all three directions
L.box(
"tilt large"
) # to avoid termination if the final simulation box has a high tilt factor
# use the OpenKIM model to set the energy interactions
L.kim("init", args.kim_model, "metal", "unit_conversion_mode")
L.read_data(args.input_data_file)
potential(L, args)
# Need to set mass to something, just to satisfy LAMMPS
mass_dictionary = {
'H': 1.00797,
'He': 4.00260,
'Li': 6.941,
'Be': 9.01218,
'B': 10.81,
'C': 12.011,
'N': 14.0067,
'O': 15.9994,
'F': 18.998403,
'Ne': 20.179,
'Na': 22.98977,
'Mg': 24.305,
'Al': 26.98154,
'Si': 28.0855,
'P': 30.97376,
'S': 32.06,
'Cl': 35.453,
'K': 39.0983,
'Ar': 39.948,
'Ca': 40.08,
'Sc': 44.9559,
'Ti': 47.90,
'V': 50.9415,
'Cr': 51.996,
'Mn': 54.9380,
'Fe': 55.847,
'Ni': 58.70,
'Co': 58.9332,
'Cu': 63.546,
'Zn': 65.38,
'Ga': 69.72,
'Ge': 72.59,
'As': 74.9216,
'Se': 78.96,
'Br': 79.904,
'Kr': 83.80,
'Rb': 85.4678,
'Sr': 87.62,
'Y': 88.9059,
'Zr': 91.22,
'Nb': 92.9064,
'Mo': 95.94,
'Tc': 98,
'Ru': 101.07,
'Rh': 102.9055,
'Pd': 106.4,
'Ag': 107.868,
'Cd': 112.41,
'In': 114.82,
'Sn': 118.69,
'Sb': 121.75,
'I': 126.9045,
'Te': 127.60,
'Xe': 131.30,
'Cs': 132.9054,
'Ba': 137.33,
'La': 138.9055,
'Ce': 140.12,
'Pr': 140.9077,
'Nd': 144.24,
'Pm': 145,
'Sm': 150.4,
'Eu': 151.96,
'Gd': 157.25,
'Tb': 158.9254,
'Dy': 162.50,
'Ho': 164.9304,
'Er': 167.26,
'Tm': 168.9342,
'Yb': 173.04,
'Lu': 174.967,
'Hf': 178.49,
'Ta': 180.9479,
'W': 183.85,
'Re': 186.207,
'Os': 190.2,
'Ir': 192.22,
'Pt': 195.09,
'Au': 196.9665,
'Hg': 200.59,
'Tl': 204.37,
'Pb': 207.2,
'Bi': 208.9804,
'Po': 209,
'At': 210,
'Rn': 222,
'Fr': 223,
'Ra': 226.0254,
'Ac': 227.0278,
'Pa': 231.0359,
'Th': 232.0381,
'Np': 237.0482,
'U': 238.029
}
for itype in range(1, len(args.elements) + 1):
L.mass(itype, mass_dictionary.get(args.elements[itype - 1], 1.0e-20))
# Compute initial state at zero pressure
L.fix(3, "all", "box/relax", "aniso", 0.0)
L.min_style(args.min_style)
L.minimize(args.minimize[0], args.minimize[1], int(args.minimize[2]),
int(args.minimize[3]))
L.variable("lx0 equal {}".format(L.eval("lx")))
L.variable("ly0 equal {}".format(L.eval("ly")))
L.variable("lz0 equal {}".format(L.eval("lz")))
# These formulas define the derivatives w.r.t. strain components
L.variable("d1 equal -(v_pxx1-{})/(v_delta/v_len0)*{}".format(
L.eval("pxx"), cfac))
L.variable("d2 equal -(v_pyy1-{})/(v_delta/v_len0)*{}".format(
L.eval("pyy"), cfac))
L.variable("d3 equal -(v_pzz1-{})/(v_delta/v_len0)*{}".format(
L.eval("pzz"), cfac))
L.variable("d4 equal -(v_pyz1-{})/(v_delta/v_len0)*{}".format(
L.eval("pyz"), cfac))
L.variable("d5 equal -(v_pxz1-{})/(v_delta/v_len0)*{}".format(
L.eval("pxz"), cfac))
L.variable("d6 equal -(v_pxy1-{})/(v_delta/v_len0)*{}".format(
L.eval("pxy"), cfac))
L.displace_atoms("all", "random", atomjiggle, atomjiggle, atomjiggle,
87287, "units box")
# Write restart
L.unfix(3)
L.write_restart("restart.equil")
for idir in range(1, 7):
displace(L, args, idir)
postprocess_and_output(L)
return