def notest_hamiltonian_exchange(mpicomm=None, verbose=True):
"""
Test that free energies and average potential energies of a 3D harmonic oscillator are correctly computed when running HamiltonianExchange.
TODO
* Integrate with test_replica_exchange.
* Test with different combinations of input parameters.
"""
if verbose and ((not mpicomm) or (mpicomm.rank==0)): sys.stdout.write("Testing Hamiltonian exchange facility with harmonic oscillators: ")
# Create test system of harmonic oscillators
testsystem = testsystems.HarmonicOscillatorArray()
[system, coordinates] = [testsystem.system, testsystem.positions]
# Define mass of carbon atom.
mass = 12.0 * units.amu
# Define thermodynamic states.
sigmas = [0.2, 0.3, 0.4] * units.angstroms # standard deviations: beta K = 1/sigma^2 so K = 1/(beta sigma^2)
temperature = 300.0 * units.kelvin # temperatures
seed_positions = list()
analytical_results = list()
f_i_analytical = list() # dimensionless free energies
u_i_analytical = list() # reduced potential
systems = list() # Systems list for HamiltonianExchange
for sigma in sigmas:
# Compute corresponding spring constant.
kB = units.BOLTZMANN_CONSTANT_kB * units.AVOGADRO_CONSTANT_NA
kT = kB * temperature # thermal energy
beta = 1.0 / kT # inverse temperature
K = 1.0 / (beta * sigma**2)
# Create harmonic oscillator system.
testsystem = testsystems.HarmonicOscillator(K=K, mass=mass, mm=openmm)
[system, positions] = [testsystem.system, testsystem.positions]
# Append to systems list.
systems.append(system)
# Append positions.
seed_positions.append(positions)
# Store analytical results.
results = computeHarmonicOscillatorExpectations(K, mass, temperature)
analytical_results.append(results)
f_i_analytical.append(results['f'])
reduced_potential = results['potential']['mean'] / kT
u_i_analytical.append(reduced_potential)
# DEBUG
print("")
print(seed_positions)
print(analytical_results)
print(u_i_analytical)
print(f_i_analytical)
print("")
# Compute analytical Delta_f_ij
nstates = len(f_i_analytical)
f_i_analytical = numpy.array(f_i_analytical)
u_i_analytical = numpy.array(u_i_analytical)
s_i_analytical = u_i_analytical - f_i_analytical
Delta_f_ij_analytical = numpy.zeros([nstates,nstates], numpy.float64)
Delta_u_ij_analytical = numpy.zeros([nstates,nstates], numpy.float64)
Delta_s_ij_analytical = numpy.zeros([nstates,nstates], numpy.float64)
for i in range(nstates):
for j in range(nstates):
Delta_f_ij_analytical[i,j] = f_i_analytical[j] - f_i_analytical[i]
Delta_u_ij_analytical[i,j] = u_i_analytical[j] - u_i_analytical[i]
Delta_s_ij_analytical[i,j] = s_i_analytical[j] - s_i_analytical[i]
# Define file for temporary storage.
import tempfile # use a temporary file
file = tempfile.NamedTemporaryFile(delete=False)
store_filename = file.name
#print("Storing data in temporary file: %s" % str(store_filename))
# Create reference thermodynamic state.
reference_state = ThermodynamicState(systems[0], temperature=temperature)
# Create and configure simulation object.
simulation = HamiltonianExchange(store_filename, mpicomm=mpicomm)
simulation.create(reference_state, systems, seed_positions)
simulation.platform = openmm.Platform.getPlatformByName('Reference')
simulation.number_of_iterations = 200
simulation.timestep = 2.0 * units.femtoseconds
simulation.nsteps_per_iteration = 500
simulation.collision_rate = 9.2 / units.picosecond
simulation.verbose = False
simulation.show_mixing_statistics = False
# Run simulation.
utils.config_root_logger(True)
simulation.run() # run the simulation
utils.config_root_logger(False)
# Stop here if not root node.
if mpicomm and (mpicomm.rank != 0): return
# Analyze simulation to compute free energies.
analysis = simulation.analyze()
# TODO: Check if deviations exceed tolerance.
Delta_f_ij = analysis['Delta_f_ij']
dDelta_f_ij = analysis['dDelta_f_ij']
error = Delta_f_ij - Delta_f_ij_analytical
indices = numpy.where(dDelta_f_ij > 0.0)
nsigma = numpy.zeros([nstates,nstates], numpy.float32)
nsigma[indices] = error[indices] / dDelta_f_ij[indices]
MAX_SIGMA = 6.0 # maximum allowed number of standard errors
if numpy.any(nsigma > MAX_SIGMA):
print("Delta_f_ij")
print(Delta_f_ij)
print("Delta_f_ij_analytical")
print(Delta_f_ij_analytical)
print("error")
print(error)
print("stderr")
print(dDelta_f_ij)
print("nsigma")
print(nsigma)
raise Exception("Dimensionless free energy difference exceeds MAX_SIGMA of %.1f" % MAX_SIGMA)
error = analysis['Delta_u_ij'] - Delta_u_ij_analytical
nsigma = numpy.zeros([nstates,nstates], numpy.float32)
nsigma[indices] = error[indices] / dDelta_f_ij[indices]
if numpy.any(nsigma > MAX_SIGMA):
print("Delta_u_ij")
print(analysis['Delta_u_ij'])
print("Delta_u_ij_analytical")
print(Delta_u_ij_analytical)
print("error")
print(error)
print("nsigma")
print(nsigma)
raise Exception("Dimensionless potential energy difference exceeds MAX_SIGMA of %.1f" % MAX_SIGMA)
if verbose: print("PASSED.")
return
from openmmtools.mcmc import *
# =============================================================================
# GLOBAL TEST CONSTANTS
# =============================================================================
# Test various combinations of systems and MCMC schemes
analytical_testsystems = [
("HarmonicOscillator", testsystems.HarmonicOscillator(),
GHMCMove(timestep=10.0 * unit.femtoseconds, n_steps=100)),
("HarmonicOscillator", testsystems.HarmonicOscillator(),
WeightedMove([(GHMCMove(timestep=10.0 * unit.femtoseconds,
n_steps=100), 0.5),
(HMCMove(timestep=10 * unit.femtosecond,
n_steps=10), 0.5)])),
("HarmonicOscillatorArray", testsystems.HarmonicOscillatorArray(N=4),
LangevinDynamicsMove(timestep=10.0 * unit.femtoseconds, n_steps=100)),
("IdealGas", testsystems.IdealGas(nparticles=216),
SequenceMove([
HMCMove(timestep=10 * unit.femtosecond, n_steps=10),
MonteCarloBarostatMove()
]))
]
NSIGMA_CUTOFF = 6.0 # cutoff for significance testing
debug = True # set to True only for manual debugging of this nose test
# =============================================================================
# TEST FUNCTIONS
# =============================================================================
def load(sysname):
cutoff = 0.9 * u.nanometers
temperature = 300. * u.kelvin
langevin_timestep = 0.5 * u.femtoseconds
timestep = 2 * u.femtoseconds
equil_steps = 40000
groups = [(0, 1)]
steps_per_hmc = 25
if sysname == "chargedljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
charge=0.15 * u.elementary_charge)
if sysname == "chargedswitchedljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
charge=0.15 * u.elementary_charge,
switch_width=0.34 * u.nanometers)
if sysname == "chargedlongljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
cutoff=1.333 * u.nanometers, charge=0.15 * u.elementary_charge)
if sysname == "chargedswitchedlongljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
cutoff=1.333 * u.nanometers,
charge=0.15 * u.elementary_charge,
switch_width=0.34 * u.nanometers)
if sysname == "chargedswitchedaccuratelongljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
cutoff=1.333 * u.nanometers,
charge=0.15 * u.elementary_charge,
switch_width=0.34 * u.nanometers,
ewaldErrorTolerance=5E-5)
if sysname == "chargedswitchedaccurateljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
charge=0.15 * u.elementary_charge,
switch_width=0.34 * u.nanometers,
ewaldErrorTolerance=5E-5)
if sysname == "ljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj()
if sysname == "longljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
cutoff=1.333 * u.nanometers)
if sysname == "shortljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
cutoff=0.90 * u.nanometers)
if sysname == "shiftedljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
shift=True)
if sysname == "switchedljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
switch_width=0.34 * u.nanometers)
if sysname == "switchedshortljbox":
testsystem, system, positions, timestep, langevin_timestep = load_lj(
cutoff=0.90 * u.nanometers, switch_width=0.34 * u.nanometers)
if sysname == "cluster":
testsystem = testsystems.LennardJonesCluster(nx=8, ny=8, nz=8)
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system, nonbonded=0)
groups = [(0, 1)]
temperature = 25. * u.kelvin
timestep = 40 * u.femtoseconds
if sysname == "shortbigcluster":
testsystem = testsystems.LennardJonesCluster(nx=20,
ny=20,
nz=20,
cutoff=0.75 *
u.nanometers)
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system, nonbonded=0)
groups = [(0, 1)]
temperature = 25. * u.kelvin
timestep = 10 * u.femtoseconds
if sysname == "switchedshortbigcluster":
testsystem = testsystems.LennardJonesCluster(
nx=20,
ny=20,
nz=20,
cutoff=0.75 * u.nanometers,
switch_width=0.1 * u.nanometers)
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system, nonbonded=0)
groups = [(0, 1)]
temperature = 25. * u.kelvin
timestep = 10 * u.femtoseconds
if sysname == "bigcluster":
testsystem = testsystems.LennardJonesCluster(nx=20,
ny=20,
nz=20,
cutoff=1.25 *
u.nanometers)
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system, nonbonded=0)
groups = [(0, 1)]
temperature = 25. * u.kelvin
timestep = 10 * u.femtoseconds
if sysname == "shortcluster":
testsystem = testsystems.LennardJonesCluster(nx=8,
ny=8,
nz=8,
cutoff=0.75 *
u.nanometers)
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system, nonbonded=0)
groups = [(0, 1)]
temperature = 25. * u.kelvin
timestep = 40 * u.femtoseconds
if sysname == "shortwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=0.9 * u.nanometers,
switch_width=None) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "shortswitchedwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=0.9 * u.nanometers,
switch_width=3.0 * u.angstroms) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "water":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
switch_width=None) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "switchedwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
switch_width=3.0 * u.angstroms) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "switchedaccuratewater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
switch_width=3.0 * u.angstroms,
ewaldErrorTolerance=5E-5) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(
system, nonbonded=0, fft=1, others=0) # We may want to try reduce
if sysname == "switchedaccurateflexiblewater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
switch_width=3.0 * u.angstroms,
ewaldErrorTolerance=5E-5,
constrained=False) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
# Using these groups for hyperopt-optimal RESPA integrators
#hmc_integrators.guess_force_groups(system, nonbonded=0, others=1, fft=0)
hmc_integrators.guess_force_groups(system,
nonbonded=1,
others=1,
fft=0)
equil_steps = 100000
langevin_timestep = 0.25 * u.femtoseconds
if sysname == "switchedaccuratebigflexiblewater":
testsystem = testsystems.WaterBox(
box_edge=10.0 * u.nanometers,
cutoff=1.1 * u.nanometers,
switch_width=3.0 * u.angstroms,
ewaldErrorTolerance=5E-5,
constrained=False) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
# Using these groups for hyperopt-optimal RESPA integrators
hmc_integrators.guess_force_groups(system,
nonbonded=1,
others=0,
fft=1)
equil_steps = 100000
langevin_timestep = 0.1 * u.femtoseconds
if sysname == "switchedaccuratestiffflexiblewater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
switch_width=3.0 * u.angstroms,
ewaldErrorTolerance=5E-5,
constrained=False) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
# Using these groups for hyperopt-optimal RESPA integrators
#hmc_integrators.guess_force_groups(system, nonbonded=0, others=1, fft=0)
hmc_integrators.guess_force_groups(system,
nonbonded=1,
others=1,
fft=0)
equil_steps = 100000
langevin_timestep = 0.25 * u.femtoseconds
FACTOR = 10.0
# Make bonded terms stiffer to highlight RESPA advantage
for force in system.getForces():
if type(force) == mm.HarmonicBondForce:
for i in range(force.getNumBonds()):
(a0, a1, length, strength) = force.getBondParameters(i)
force.setBondParameters(i, a0, a1, length,
strength * FACTOR)
elif type(force) == mm.HarmonicAngleForce:
for i in range(force.getNumAngles()):
(a0, a1, a2, length,
strength) = force.getAngleParameters(i)
force.setAngleParameters(i, a0, a1, a2, length,
strength * FACTOR)
if sysname == "switchedaccuratenptwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
switch_width=3.0 * u.angstroms,
ewaldErrorTolerance=5E-5) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
system.addForce(
mm.MonteCarloBarostat(1.0 * u.atmospheres, temperature, 1))
if sysname == "longswitchedwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.5 * u.nanometers,
switch_width=3.0 * u.angstroms) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "rfwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
nonbondedMethod=app.CutoffPeriodic,
switch_width=None) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "switchedrfwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.1 * u.nanometers,
nonbondedMethod=app.CutoffPeriodic,
switch_width=3.0 * u.angstroms) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "longswitchedrfwater":
testsystem = testsystems.WaterBox(
box_edge=3.18 * u.nanometers,
cutoff=1.5 * u.nanometers,
nonbondedMethod=app.CutoffPeriodic,
switch_width=3.0 * u.angstroms) # Around 1060 molecules of water
system, positions = testsystem.system, testsystem.positions
if sysname == "density":
system, positions = load_lb(hydrogenMass=3.0 * u.amu)
hmc_integrators.guess_force_groups(system,
nonbonded=1,
fft=1,
others=0)
groups = [(0, 4), (1, 1)]
timestep = 2.0 * u.femtoseconds
if sysname == "dhfr":
testsystem = testsystems.DHFRExplicit(nonbondedCutoff=1.1 *
u.nanometers,
nonbondedMethod=app.PME,
switch_width=2.0 * u.angstroms,
ewaldErrorTolerance=5E-5)
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system,
nonbonded=1,
fft=2,
others=0)
groups = [(0, 4), (1, 2), (2, 1)]
timestep = 0.75 * u.femtoseconds
equil_steps = 10000
if sysname == "src":
testsystem = testsystems.SrcExplicit(nonbondedCutoff=1.1 *
u.nanometers,
nonbondedMethod=app.PME,
switch_width=2.0 * u.angstroms,
ewaldErrorTolerance=5E-5)
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system,
nonbonded=1,
fft=1,
others=0)
groups = [(0, 2), (1, 1)]
timestep = 0.25 * u.femtoseconds
equil_steps = 1000
if sysname == "ho":
K = 90.0 * u.kilocalories_per_mole / u.angstroms**2
mass = 39.948 * u.amu
timestep = np.sqrt(mass / K) * 0.4
testsystem = testsystems.HarmonicOscillatorArray()
system, positions = testsystem.system, testsystem.positions
groups = [(0, 1)]
if sysname == "customho":
timestep = 1000.0 * u.femtoseconds
testsystem = testsystems.CustomExternalForcesTestSystem()
system, positions = testsystem.system, testsystem.positions
groups = [(0, 1)]
if sysname == "customsplitho":
timestep = 1000.0 * u.femtoseconds
energy_expressions = ("0.75 * (x^2 + y^2 + z^2)",
"0.25 * (x^2 + y^2 + z^2)")
testsystem = testsystems.CustomExternalForcesTestSystem(
energy_expressions=energy_expressions)
system, positions = testsystem.system, testsystem.positions
groups = [(0, 2), (1, 1)]
if sysname == "alanine":
testsystem = testsystems.AlanineDipeptideImplicit()
system, positions = testsystem.system, testsystem.positions
groups = [(0, 2), (1, 1)]
timestep = 2.0 * u.femtoseconds
hmc_integrators.guess_force_groups(system, nonbonded=1, others=0)
#remove_cmm(system) # Unrolled shouldn't need this
equil_steps = 10000
if sysname == "alanineexplicit":
testsystem = testsystems.AlanineDipeptideExplicit(
cutoff=1.1 * u.nanometers,
switch_width=2 * u.angstrom,
ewaldErrorTolerance=5E-5)
system, positions = testsystem.system, testsystem.positions
#groups = [(0, 2), (1, 1), (2, 1)]
#groups = [(0, 2), (1, 1)]
timestep = 1.0 * u.femtoseconds
#hmc_integrators.guess_force_groups(system, nonbonded=1, others=0, fft=2)
#hmc_integrators.guess_force_groups(system, nonbonded=0, others=0, fft=1)
groups = [(0, 1), (1, 2)]
hmc_integrators.guess_force_groups(system,
nonbonded=0,
others=1,
fft=0)
#remove_cmm(system) # Unrolled doesn't need this
equil_steps = 4000
# guess force groups
if "ljbox" in sysname:
timestep = 25 * u.femtoseconds
temperature = 25. * u.kelvin
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system, nonbonded=0, fft=1)
groups = [(0, 2), (1, 1)]
equil_steps = 10000
steps_per_hmc = 15
if sysname == "amoeba":
testsystem = testsystems.AMOEBAIonBox()
system, positions = testsystem.system, testsystem.positions
hmc_integrators.guess_force_groups(system,
nonbonded=0,
fft=1,
others=0)
return system, positions, groups, temperature, timestep, langevin_timestep, testsystem, equil_steps, steps_per_hmc
import simtk.unit as units
import openmmtools.testsystems
from openmmtools import testsystems
from pymbar import timeseries
from functools import partial
from openmmmcmc.mcmc import HMCMove, GHMCMove, LangevinDynamicsMove, MonteCarloBarostatMove
import logging
# Test various combinations of systems and MCMC schemes
analytical_testsystems = [
("HarmonicOscillator", testsystems.HarmonicOscillator(), [ GHMCMove(timestep=10.0*units.femtoseconds,nsteps=100) ]),
("HarmonicOscillator", testsystems.HarmonicOscillator(), { GHMCMove(timestep=10.0*units.femtoseconds,nsteps=100) : 0.5, HMCMove(timestep=10*units.femtosecond, nsteps=10) : 0.5 }),
("HarmonicOscillatorArray", testsystems.HarmonicOscillatorArray(N=4), [ LangevinDynamicsMove(timestep=10.0*units.femtoseconds,nsteps=100) ]),
("IdealGas", testsystems.IdealGas(nparticles=216), [ HMCMove(timestep=10*units.femtosecond, nsteps=10), MonteCarloBarostatMove() ])
]
NSIGMA_CUTOFF = 6.0 # cutoff for significance testing
debug = False # set to True only for manual debugging of this nose test
def test_minimizer_all_testsystems():
#testsystem_classes = testsystems.TestSystem.__subclasses__()
testsystem_classes = [ testsystems.AlanineDipeptideVacuum ]
for testsystem_class in testsystem_classes:
class_name = testsystem_class.__name__
logging.info("Testing minimization with testsystem %s" % class_name)