HPMCIntegrator

class hoomd.hpmc.integrate.HPMCIntegrator(default_d, default_a, translation_move_probability, nselect, kT)

Bases: Integrator

Base class hard particle Monte Carlo integrator.

HPMCIntegrator is the base class for all HPMC integrators. The attributes documented here are available to all HPMC integrators.

See also

The module level documentation hoomd.hpmc.integrate describes the hard particle Monte Carlo algorithm.

Warning

This class should not be instantiated by users. The class can be used for isinstance or issubclass checks.

Ignoring overlap checks

Set elements of interaction_matrix to False to disable overlap checks between specific pairs of particle types.

Writing type_shapes to GSD files.

Use a Logger in combination with a HPMC integrator and a GSD writer to write type_shapes to the GSD file for use with OVITO. For example:

mc = hoomd.hpmc.integrate.Sphere()
log = hoomd.logging.Logger()
log.add(mc, quantities=['type_shapes'])
gsd = hoomd.write.GSD(
    'trajectory.gsd', hoomd.trigger.Periodic(1000), log=log)

Mixed precision

All HPMC integrators use reduced precision floating point arithmetic when checking for particle overlaps in the local particle reference frame.

---

Members inherited from AutotunedObject:

property kernel_parameters

Kernel parameters. Read more...

property is_tuning_complete

Check if kernel parameter tuning is complete. Read more...

tune_kernel_parameters()

Start tuning kernel parameters. Read more...

---

Members defined in HPMCIntegrator:

a

Maximum size of rotation trial moves \([\mathrm{dimensionless}]\).

Type:

TypeParameter [particle type, float]

d

Maximum size of displacement trial moves \([\mathrm{length}]\).

Type:

TypeParameter [particle type, float]

interaction_matrix

Set to False for a pair of particle types to disable overlap checks between particles of those types (default: True).

Type:

TypeParameter [ tuple [particle type, particle type], bool]

translation_move_probability

Fraction of moves to be selected as translation moves.

Type:

float

nselect

Number of trial moves to perform per particle per timestep.

Type:

int

kT

Temperature set point \([\mathrm{energy}]\).

Type:

hoomd.variant.Variant

property counters

Trial move counters.

The counter object has the following attributes:

• translate: tuple [int, int] - Number of accepted and rejected translate trial moves.

• rotate: tuple [int, int] - Number of accepted and rejected rotate trial moves.

• overlap_checks: int - Number of overlap checks performed.

• overlap_errors: int - Number of overlap checks that were too close to resolve.

Note

The counts are reset to 0 at the start of each hoomd.Simulation.run.

Type:

dict

property external_energy

Total external energy contributed by all external potentials \([\mathrm{energy}]\).

(Loggable: category=”scalar”)

Type:

float

property external_potentials

External potentials to apply.

Defines the external energy \(U_{\mathrm{external},i}\) as the sum over all potentials in the list.

Example

simulation.operations.integrator.external_potentials = [linear]

Type:

list[hoomd.hpmc.external.External]

property map_overlaps

List of overlapping particles.

The list contains one entry for each overlapping pair of particles. When a tuple (i,j) is present in the list, there is an overlap between the particles with tags i and j.

Attention

map_overlaps does not support MPI parallel simulations. It returns None when there is more than one MPI rank.

(Loggable: category=”sequence”)

Type:

list[tuple[int, int]]

property mps

Number of trial moves performed per second.

Note

The count is reset at the start of each hoomd.Simulation.run.

(Loggable: category=”scalar”)

Type:

float

property overlaps

Number of overlapping particle pairs.

(Loggable: category=”scalar”)

Type:

int

property pair_energy

Total potential energy contributed by all pair potentials \([\mathrm{energy}]\).

(Loggable: category=”scalar”)

Type:

float

property pair_potentials

Pair potentials to apply.

Defines the pairwise particle interaction energy \(U_{\mathrm{pair},ij}\) as the sum over all potentials in the list.

Example

simulation.operations.integrator.pair_potentials = [lennard_jones]

Type:

list[hoomd.hpmc.pair.Pair]

property rotate_moves

Count of the accepted and rejected rotate moves.

Note

The counts are reset to 0 at the start of each hoomd.Simulation.run.

(Loggable: category=”sequence”)

Type:

tuple[int, int]

property translate_moves

Count of the accepted and rejected translate moves.

Note

The counts are reset to 0 at the start of each hoomd.Simulation.run.

(Loggable: category=”sequence”)

Type:

tuple[int, int]