newton.eval_jacobian

newton.eval_jacobian(model, state, J=None, joint_S_s=None, mask=None)

Evaluate spatial Jacobian for articulations.

Computes the spatial Jacobian J that maps joint velocities to spatial velocities of each link in world frame. The Jacobian is computed for each articulation in the model.

Parameters:

• model (Model) – The model containing articulation definitions.

• state (State) – The state containing body transforms (body_q).

• J (array | None) – Optional output array for the Jacobian, shape (articulation_count, max_links*6, max_dofs). If None, allocates internally.

• joint_S_s (array | None) – Optional pre-allocated temp array for motion subspaces, shape (joint_dof_count,), dtype wp.spatial_vector. If None, allocates internally.

• mask (array | None) – Optional boolean mask to select which articulations to compute. Shape [articulation_count]. If None, computes for all articulations.

Returns:

The Jacobian array J, or None if the model has no articulations.

Return type:

array | None