newton.solvers.SolverBase#

class newton.solvers.SolverBase(model)[source]#

Bases: object

Generic base class for solvers.

The implementation provides helper kernels to integrate rigid bodies and particles. Concrete solver back-ends should derive from this class and override step() as well as notify_model_changed() where necessary.

classmethod register_custom_attributes(builder)#

Register custom attributes for the solver.

Parameters:

builder (ModelBuilder) – The model builder to register the custom attributes to.

__init__(model)#
integrate_bodies(model, state_in, state_out, dt, angular_damping=0.0)#

Integrate the rigid bodies of the model.

Parameters:

  • model (Model) – The model to integrate.

  • state_in (State) – The input state.

  • state_out (State) – The output state.

  • dt (float) – The time step (typically in seconds).

  • angular_damping (float, optional) – The angular damping factor. Defaults to 0.0.

integrate_particles(model, state_in, state_out, dt)#

Integrate the particles of the model.

Parameters:

  • model (Model) – The model to integrate.

  • state_in (State) – The input state.

  • state_out (State) – The output state.

  • dt (float) – The time step (typically in seconds).

notify_model_changed(flags)#

Notify the solver that parts of the Model were modified.

The flags argument is a bit-mask composed of the SolverNotifyFlags enums defined in newton.solvers. Each flag represents a category of model data that may have been updated after the solver was created. Passing the appropriate combination of flags enables a solver implementation to refresh its internal buffers without having to recreate the whole solver object. Valid flags are:

Constant

Description

SolverNotifyFlags.JOINT_PROPERTIES

Joint transforms or coordinates have changed.

SolverNotifyFlags.JOINT_DOF_PROPERTIES

Joint axis limits, targets, modes, DOF state, or force buffers have changed.

SolverNotifyFlags.BODY_PROPERTIES

Rigid-body pose or velocity buffers have changed.

SolverNotifyFlags.BODY_INERTIAL_PROPERTIES

Rigid-body mass or inertia tensors have changed.

SolverNotifyFlags.SHAPE_PROPERTIES

Shape transforms or geometry have changed.

SolverNotifyFlags.MODEL_PROPERTIES

Model global properties (e.g., gravity) have changed.
Parameters:

flags (int) – Bit-mask of model-update flags indicating which model properties changed.

step(state_in, state_out, control, contacts, dt)#

Simulate the model for a given time step using the given control input.

Parameters:

  • state_in (State) – The input state.

  • state_out (State) – The output state.

  • control (Control) – The control input. Defaults to None which means the control values from the Model are used.

  • contacts (Contacts) – The contact information.

  • dt (float) – The time step (typically in seconds).

update_contacts(contacts)#

Update a Contacts object with forces from the solver state. Where the solver state contains other contact data, convert that data to the Contacts format.

Parameters:

contacts (Contacts) – The object to update from the solver state.

property device: Device#

Get the device used by the solver.

Returns:

The device used by the solver.

Return type:

wp.Device