BoxMCMoveSize¶

class hoomd.hpmc.tune.BoxMCMoveSize(trigger, boxmc, moves, target, solver, max_move_size=None)¶

Tunes BoxMC move sizes to targeted acceptance rate.

Tip

For most common creation of a BoxMCMoveSize tuner see BoxMCMoveSize.secant_solver and BoxMCMoveSize.scale_solver respectively.

The tuner will continue tuning despite being tuned. Thus, if simulation conditions change the move sizes will continue to change and the tuner will no longer be tuned. The changes to the move size are completely controlled by the given hoomd.tune.RootSolver instance. See the documentation at hoomd.tune for more information.

Warning

The tuner should be removed from the simulation once tuned to prevent invalid results due to the breaking of balance.

Parameters:

trigger (hoomd.trigger.trigger_like) – Trigger to determine when to run the tuner.
boxmc (hoomd.hpmc.update.BoxMC) – The hoomd.hpmc.update.BoxMC object to tune.
moves (list[str]) – A list of types of moves to tune. Available options are ‘volume’, ‘aspect’, ‘shear_{x,y,z}’, and ‘length_{x,y,z}’ where brackets denote multiple options. For shear and length moves each dimension is tuned independently.
target (float) – The acceptance rate for trial moves that is desired. The value should be between 0 and 1.
solver (hoomd.tune.RootSolver) – A solver that tunes move sizes to reach the specified target.
max_move_size (dict [str, float ], optional) – The maximum volume move size to attempt for each move time. See the available moves in the moves attribute documentation. Defaults to no maximum None for each move type.

Warning

Over-limiting the maximum move sizes can lead to the inability to converge to the desired acceptance rate.

Warning

Since each dimension of length and shear moves are tuned independently but the acceptance statistics are collected collectively, the reachable target acceptance rates is limited by the other dimensions.

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 inherited from TriggeredOperation:

trigger¶: The trigger to activate this operation. Read more...

Members defined in BoxMCMoveSize:

boxmc¶

The hoomd.hpmc.update.BoxMC object to tune.

Type:: hoomd.hpmc.update.BoxMC

moves¶

A list of types of moves to tune. Available options are ‘volume’, ‘aspect’, ‘shear_{x,y,z}’, and ‘length_{x,y,z}’ where brackets denote multiple options. For shear and length moves each dimension is tuned independently.

Type:: list[str]

target¶

The acceptance rate for trial moves that is desired. The value should be between 0 and 1.

Type:: float

solver¶

A solver that tunes move sizes to reach the specified target.

Type:: hoomd.tune.RootSolver

max_move_size¶

The maximum volume move size to attempt for each move time. See the available moves in the moves attribute documentation.

Type:: float

classmethod scale_solver(trigger, boxmc, moves, target, max_move_size=None, max_scale=2.0, gamma=1.0, tol=0.01)¶

Create a BoxMCMoveSize tuner with a hoomd.tune.ScaleSolver.

Parameters:

trigger (hoomd.trigger.trigger_like) – Trigger to determine when to run the tuner.
boxmc (hoomd.hpmc.update.BoxMC) – The hoomd.hpmc.update.BoxMC object to tune.
moves (list[str]) – A list of types of moves to tune. Available options are ‘volume’, ‘aspect’, ‘shear_{x,y,z}’, and ‘length_{x,y,z}’ where brackets denote multiple options. For shear and length moves each dimension is tuned independently.
target (float) – The acceptance rate for trial moves that is desired. The value should be between 0 and 1.
max_move_size (float) – The maximum value of a volume move size to attempt.
max_scale (float) – Maximum scale factor.
gamma (float) – The value of gamma to pass through to hoomd.tune.ScaleSolver. Controls the size of corrections to the move size (larger values increase stability while increasing convergence time).
tol (float) – The absolute tolerance to allow between the current acceptance rate and the target before the move sizes are considered tuned. The tolerance should not be too much lower than the default of 0.01 as acceptance rates can vary significantly at typical tuning rates.

classmethod secant_solver(trigger, boxmc, moves, target, max_move_size=None, gamma=0.8, tol=0.01)¶

Create a BoxMCMoveSize tuner with a hoomd.tune.SecantSolver.

This solver can be faster than hoomd.tune.ScaleSolver, but depending on the system slightly less stable. In general, with the default value of gamma this should not be a problem.

Parameters:

trigger (hoomd.trigger.trigger_like) – Trigger to determine when to run the tuner.
boxmc (hoomd.hpmc.update.BoxMC) – The hoomd.hpmc.update.BoxMC object to tune.
moves (list[str]) – A list of types of moves to tune. Available options are ‘volume’, ‘aspect’, ‘shear_{x,y,z}’, and ‘length_{x,y,z}’ where brackets denote multiple options. For shear and length moves each dimension is tuned independently.
target (float) – The acceptance rate for trial moves that is desired. The value should be between 0 and 1.
max_move_size (float) – The maximum value of a volume move size to attempt, defaults to None which represents no maximum move size.
gamma (float) – The value of gamma to pass through to hoomd.tune.SecantSolver. Controls the size of corrections to the move size (smaller values increase stability). Should be between 0 and 1, defaults to 0.8.
tol (float) – The absolute tolerance to allow between the current acceptance rate and the target before the move sizes are considered tuned. The tolerance should not be too much lower than the default of 0.01 as acceptance rates can vary significantly at typical tuning rates.

Note

Increasing gamma towards 1 does not necessarily speed up convergence and can slow it down. In addition, large values of gamma can make the solver unstable, especially when tuning frequently.

property tuned¶

Whether or not the move sizes are considered tuned.

An instance is considered tuned if it the solver tolerance has been met by all tunables for 2 iterations.

Type:: bool