Rename ODEState.contact_state to ODEState.contact

Co-authored-by: Diego Ferigo <[email protected]>

src/jaxsim/api/contact.py

@@ -150,7 +150,7 @@ def collidable_point_dynamics(
             # Note that the material deformation rate is always returned in the mixed frame
             # C[W] = (W_p_C, [W]). This is convenient for integration purpose.
             W_f_Ci, CW_ṁ = jax.vmap(soft_contacts.compute_contact_forces)(
-                W_p_Ci, W_ṗ_Ci, data.state.contacts_state.tangential_deformation
+                W_p_Ci, W_ṗ_Ci, data.state.contact.tangential_deformation
             )
 
         case _:

src/jaxsim/api/data.py

@@ -113,7 +113,7 @@ def build(
         base_angular_velocity: jtp.Vector | None = None,
         joint_velocities: jtp.Vector | None = None,
         standard_gravity: jtp.FloatLike = jaxsim.math.StandardGravity,
-        contacts_state: jaxsim.rbda.ContactsState | None = None,
+        contact: jaxsim.rbda.ContactsState | None = None,
         contacts_params: jaxsim.rbda.ContactsParams | None = None,
         velocity_representation: VelRepr = VelRepr.Inertial,
         time: jtp.FloatLike | None = None,
@@ -132,7 +132,7 @@ def build(
                 The base angular velocity in the selected representation.
             joint_velocities: The joint velocities.
             standard_gravity: The standard gravity constant.
-            contacts_state: The state of the soft contacts.
+            contact: The state of the soft contacts.
             contacts_params: The parameters of the soft contacts.
             velocity_representation: The velocity representation to use.
             time: The time at which the state is created.
@@ -213,9 +213,8 @@ def build(
             base_angular_velocity=v_WB[3:6].astype(float),
             joint_velocities=joint_velocities.astype(float),
             tangential_deformation=(
-                contacts_state.tangential_deformation
-                if contacts_state is not None
-                and isinstance(model.contact_model, SoftContacts)
+                contact.tangential_deformation
+                if contact is not None and isinstance(model.contact_model, SoftContacts)
                 else None
             ),
         )

src/jaxsim/api/ode.py

@@ -132,7 +132,7 @@ def system_velocity_dynamics(
     W_f_Ci = None
 
     # Initialize the derivative of the tangential deformation ṁ ∈ ℝ^{n_c × 3}.
-    ṁ = jnp.zeros_like(data.state.contacts_state.tangential_deformation).astype(float)
+    ṁ = jnp.zeros_like(data.state.contact.tangential_deformation).astype(float)
 
     if len(model.kin_dyn_parameters.contact_parameters.body) > 0:
         # Compute the 6D forces applied to each collidable point and the

src/jaxsim/api/ode_data.py

@@ -121,11 +121,11 @@ class ODEState(JaxsimDataclass):
 
     Attributes:
         physics_model: The state of the physics model.
-        contacts_state: The state of the contacts model.
+        contact: The state of the contacts model.
     """
 
     physics_model: PhysicsModelState
-    contacts_state: ContactsState
+    contact: ContactsState
 
     @staticmethod
     def build_from_jaxsim_model(
@@ -183,7 +183,7 @@ def build_from_jaxsim_model(
                 base_linear_velocity=base_linear_velocity,
                 base_angular_velocity=base_angular_velocity,
             ),
-            contacts_state=getattr(
+            contact=getattr(
                 importlib.import_module(f"jaxsim.rbda.contacts.{module_name}"),
                 class_name,
             ).build_from_jaxsim_model(
@@ -199,15 +199,15 @@ def build_from_jaxsim_model(
     @staticmethod
     def build(
         physics_model_state: PhysicsModelState | None = None,
-        contacts_state: ContactsState | None = None,
+        contact: ContactsState | None = None,
         model: js.model.JaxSimModel | None = None,
     ) -> ODEState:
         """
         Build an `ODEState` from a `PhysicsModelState` and a `ContactsState`.
 
         Args:
             physics_model_state: The state of the physics model.
-            contacts_state: The state of the contacts model.
+            contact: The state of the contacts model.
             model: The `JaxSimModel` associated with the ODE state.
 
         Returns:
@@ -240,15 +240,11 @@ def build(
         except ImportError as e:
             raise e
 
-        contacts_state = (
-            contacts_state
-            if contacts_state is not None
-            else SoftContactsState.zero(model=model)
+        contact = (
+            contact if contact is not None else SoftContactsState.zero(model=model)
         )
 
-        return ODEState(
-            physics_model=physics_model_state, contacts_state=contacts_state
-        )
+        return ODEState(physics_model=physics_model_state, contact=contact)
 
     @staticmethod
     def zero(model: js.model.JaxSimModel) -> ODEState:
@@ -277,9 +273,7 @@ def valid(self, model: js.model.JaxSimModel) -> bool:
             `True` if the ODE state is valid for the given model, `False` otherwise.
         """
 
-        return self.physics_model.valid(model=model) and self.contacts_state.valid(
-            model=model
-        )
+        return self.physics_model.valid(model=model) and self.contact.valid(model=model)
 
 
 # ==================================================

tests/test_automatic_differentiation.py

@@ -342,7 +342,7 @@ def test_ad_integration(
     s = data.joint_positions(model=model)
     W_v_WB = data.base_velocity()
     ṡ = data.joint_velocities(model=model)
-    m = data.state.contacts_state.tangential_deformation
+    m = data.state.contact.tangential_deformation
 
     # Inputs.
     W_f_L = references.link_forces(model=model)
@@ -396,9 +396,7 @@ def step(
                     base_angular_velocity=W_v_WB[3:6],
                     joint_velocities=ṡ,
                 ),
-                contacts_state=js.ode_data.SoftContactsState.build(
-                    tangential_deformation=m
-                ),
+                contact=js.ode_data.SoftContactsState.build(tangential_deformation=m),
             ),
         )
 
@@ -417,7 +415,7 @@ def step(
         xf_s = data_xf.joint_positions(model=model)
         xf_W_v_WB = data_xf.base_velocity()
         xf_ṡ = data_xf.joint_velocities(model=model)
-        xf_m = data_xf.state.contacts_state.tangential_deformation
+        xf_m = data_xf.state.contact.tangential_deformation
 
         return xf_W_p_B, xf_W_Q_B, xf_s, xf_W_v_WB, xf_ṡ, xf_m