Modules

class hoomd_flowws.Init(**kwargs)

Initialize a system

Currently simply places points on a simple cubic lattice.

Parameters:

• number – Number of particles to simulate
• mass_scale – Scaling factor for mass of all particles
• type_ratios – Prevalence (ratio) of each particle type

run(scope, storage)

Run the contents of this stage

class hoomd_flowws.Interaction(**kwargs)

Specify a new interaction potential to include in future MD stages

Parameters:

• reset – Clear previously-defined interactions beforehand
• type – Interaction class name
• global_params – Global parameters of the interaction
• pair_params – Type pair-based parameters of the interaction

classmethod register_interaction(interaction, *names)

Convenience method to bind one or more names to a force-generation function

run(scope, storage)

Registers this object to provide a force compute in future MD stages

class hoomd_flowws.ShapeDefinition(**kwargs)

Define per-type shapes for future stages to utilize

Shape information is used for visualization, packing fraction calculations, and pair force/HPMC integrator configuration.

Shapes consist of a base type, any parameters of the shape, and modifications. For example:

# regular polygon with 4 vertices (square)
shape = dict(type='regular_ngon', n=4,
             modifications=[dict(type='scale', factor=2)])
# rounded tetrahedron
shape = dict(type='tetrahedron',
             modifications=[dict(type='round', radius=0.5)])
ShapeDefinition(shape_arguments=[shape])

Parameters:shape_arguments – List of per-shape specifications and modifiers.

run(scope, storage)

Run the contents of this stage

class hoomd_flowws.DEMInteraction(**kwargs)

Specify that DEM interactions should be included in future MD stages

Parameters:

• reset – Clear previously-defined DEM interactions beforehand
• type – Interaction class name

run(scope, storage)

Registers this object to provide a DEM force compute in future MD stages

class hoomd_flowws.Run(**kwargs)

Run for a given number of timesteps using MD

Parameters:

• steps – Number of timesteps to run
• timestep_size – Timestep size
• integrator – Integrator type
• temperature – Temperature for isothermal simulations
• ramp_t_to – Ramp temperature to the given value over time during this stage
• tau_t – Thermostat time constant for isothermal simulations
• pressure – Pressure for isobaric simulations
• tau_p – Barostat time constant for isobaric simulations
• bd_seed – Random number seed for Brownian/Langevin thermostats
• zero_momentum – Period for zeroing the momentum of the system (default: disabled)
• backup_period – Period for dumping a backup file
• dump_period – Period for dumping a trajectory file
• trajectory_quantities – Additional trajectory quantities to dump
• dump_quantities – Dump period and comma-separated list of quantities to record (i.e. temperature,pressure)
• expand_by – Expand each dimension of the box by this ratio during this stage
• compress_to – Compress to the given packing fraction during this stage (overrides expand_by)

run(scope, storage)

Run the contents of this stage

class hoomd_flowws.RunHPMC(**kwargs)

Run for some number of steps using HPMC

Parameters:

• steps – Number of timesteps to run
• integrator – Integrator type
• pressure – Pressure for isobaric simulations
• backup_period – Period for dumping a backup file
• dump_period – Period for dumping a trajectory file
• expand_by – Expand each dimension of the box by this ratio during this stage
• compress_to – Compress to the given packing fraction during this stage (overrides expand_by)
• integrator_seed – Random number seed for integration method
• tune – Tune move distances to achieve the target acceptance ratio after updating a given number of epochs and running the given number of steps at each epoch
• box_move_aspect – Move distance and weight for box aspect ratio moves
• box_move_length – Move distance and weight for box length moves
• box_move_ln_volume – Move distance and weight for box log-volume moves
• box_move_shear – Move distance and weight for box shear moves
• box_move_volume – Move distance and weight for box volume moves