Operations

class hoomd.Operations

A mutable collection of operations which act on a Simulation.

An Operations class instance contains all the operations acting on a simulation. These operations are classes that perform various actions on a hoomd.Simulation. Operations can be added and removed at any point from a hoomd.Operations instance. The class provides the interface defined by collections.abc.Collection. Other methods for manipulating instances mimic Python objects where possible, but the class is not simply a mutable list or set. Operations objects manage multiple independent sequences described below.

The types of operations which can be added to an Operations object are tuners, updaters, integrators, writers, and computes. An Operations instance can have zero or one integrator and any number of tuners, updaters, writers, or computes. To see examples of these types of operations see hoomd.tune (tuners), hoomd.update (updaters), hoomd.hpmc.integrate or hoomd.md.Integrator (integrators), hoomd.write (writers), and hoomd.md.compute.ThermodynamicQuantities (computes).

A given instance of an operation class can only be added to a single Operations container. Likewise, a single instance cannot be added to the same Operations container more than once.

All Operations instances start with a hoomd.tune.ParticleSorter instance in their tuners attribute. This increases simulation performance. However, users can choose to modify or remove this tuner if desired.

Note

An Operations object is created by default when a new simulation is created.

__contains__(operation)

Whether an operation is contained in this container.

Parameters:

operation – Returns whether this exact operation is contained in the collection.

Example:

operation in simulation.operations

__getstate__()

Get the current state of the operations container for pickling.

__iadd__(operation)

Works the same as Operations.add.

Parameters:

operation (hoomd.operation.Operation) – A HOOMD-blue tuner, updater, integrator, writer, or compute to add to the object.

Example:

simulation.operations += operation

__isub__(operation)

Works the same as Operations.remove.

Parameters:

operation (hoomd.operation.Operation) – A HOOMD-blue integrator, tuner, updater, integrator, analyzer, or compute to remove from the collection.

Example:

simulation.operations -= operation

__iter__()

Iterates through all contained operations.

Example:

for operation in simulation.operations:
    pass

__len__()

Return the number of operations contained in this collection.

Example:

len(simulation.operations)

add(operation)

Add an operation to this container.

Adds the provided operation to the appropriate attribute of the Operations instance.

Parameters:

operation (hoomd.operation.Operation) – A HOOMD-blue tuner, updater, integrator, writer, or compute to add to the collection.

Raises:

TypeError – If operation is not of a valid type.

Note

Since only one integrator can be associated with an Operations object at a time, this removes the current integrator when called with an integrator operation. Also, the integrator property cannot be set to None using this function. Use operations.integrator = None explicitly for this.

Example:

simulation.operations.add(operation)

property computes

A list of compute operations.

Holds the list of computes associated with this collection. The list can be modified as a standard Python list.

Type:

list[hoomd.operation.Compute]

property integrator

An MD or HPMC integrator object.

Operations objects have an initial integrator property of None. Can be set to MD or HPMC integrators. The property can also be set to None.

Examples:

simulation.operations.integrator = hoomd.md.Integrator(dt=0.001)

simulation.operations.integrator = None

Type:

hoomd.operation.Integrator

property is_tuning_complete

Check whether all children have completed tuning.

True when is_tuning_complete is True for all children.

Note

In MPI parallel execution, is_tuning_complete is True only when all children on all ranks have completed tuning.

See also

hoomd.operation.AutotunedObject.is_tuning_complete

Example:

while not simulation.operations.is_tuning_complete:
    simulation.run(1000)

Type:

bool

remove(operation)

Remove an operation from the Operations object.

Remove the item from the collection whose Python object id is the same as operation.

Parameters:

operation (hoomd.operation.Operation) – A HOOMD-blue integrator, tuner, updater, integrator, or compute to remove from the container.

Raises:

• ValueError – If operation is not found in this container.

• TypeError – If operation is not of a valid type.

Example:

simulation.operations.remove(operation)

tune_kernel_parameters()

Start tuning kernel parameters in all children.

See also

hoomd.operation.AutotunedObject.tune_kernel_parameters

Example:

simulation.operations.tune_kernel_parameters()

property tuners

A list of tuner operations.

Holds the list of tuners associated with this collection. The list can be modified as a standard Python list.

Type:

list[hoomd.operation.Tuner]

property updaters

A list of updater operations.

Holds the list of updaters associated with this collection. The list can be modified as a standard Python list.

Type:

list[hoomd.operation.Updater]

property writers

A list of writer operations.

Holds the list of writers associated with this collection. The list can be modified as a standard Python list.

Type:

list[hoomd.operation.Writer]