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Remove and deprecate context manager for switching velocity representation #496

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15aa4cc
Add deprecation warning to `switch_velocity_representation`
flferretti Dec 17, 2025
722fb74
Allow passing input/output representation in references
flferretti Dec 17, 2025
21a6545
Accept output velrepr in `JaxSimModelData` getters
flferretti Dec 17, 2025
29a23ba
Allow setting a velocity representation in idyntree helper
flferretti Dec 18, 2025
aff84c6
Refactor tests to the new API
flferretti Dec 18, 2025
9fe310f
Remove velrepr switch tests
flferretti Dec 18, 2025
176f6f4
Allow passing `output_representation` to `com` API
flferretti Dec 18, 2025
fe3d12f
Allow passing `output_representation` to `model` API
flferretti Dec 18, 2025
1442964
Remove velrepr switches from contact models
flferretti Dec 18, 2025
8d6ba9f
Remove velrepr switch from kinematic constraints RBDA
flferretti Dec 18, 2025
015c88e
Remove velrepr switch from examples
flferretti Dec 18, 2025
cc3764d
Allow passing `output_representation` to `contact` API
flferretti Dec 18, 2025
1c6d387
Remove velrepr switch from `integrators` API
flferretti Dec 18, 2025
c9d662c
Allow passing `output_representation` to `ode` API
flferretti Dec 18, 2025
6b2c6b4
Allow passing `output_representation` to `link` API
flferretti Dec 18, 2025
ac6410f
Allow passing a representation to `JaxSimModelData.replace`
flferretti Dec 18, 2025
7f92968
Remove velrepr switch from `frame` API
flferretti Dec 19, 2025
6e62fd7
Apply suggestions from code review
flferretti Feb 25, 2026
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122 changes: 70 additions & 52 deletions examples/jaxsim_as_multibody_dynamics_library.ipynb
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Original file line number Diff line number Diff line change
Expand Up @@ -261,7 +261,7 @@
"\n",
"# Print the default state.\n",
"W_H_B, s = data.generalized_position\n",
"ν = data.generalized_velocity\n",
"ν = data.generalized_velocity()\n",
"\n",
"print(f\"W_H_B: shape={W_H_B.shape}\\n{W_H_B}\\n\")\n",
"print(f\"s: shape={s.shape}\\n{s}\\n\")\n",
Expand Down Expand Up @@ -304,7 +304,9 @@
")\n",
"\n",
"print(f\"link_forces: shape={references.link_forces(model=model, data=data).shape}\")\n",
"print(f\"joint_force_references: shape={references.joint_force_references(model=model).shape}\")"
"print(\n",
" f\"joint_force_references: shape={references.joint_force_references(model=model).shape}\"\n",
")"
]
},
{
Expand Down Expand Up @@ -382,9 +384,15 @@
"# @title Link 6D Velocity\n",
"\n",
"# JaxSim allows to select the so-called representation of the frame velocity.\n",
"L_v_WL = js.link.velocity(model=model, data=data, link_index=link_index, output_vel_repr=VelRepr.Body)\n",
"LW_v_WL = js.link.velocity(model=model, data=data, link_index=link_index, output_vel_repr=VelRepr.Mixed)\n",
"W_v_WL = js.link.velocity(model=model, data=data, link_index=link_index, output_vel_repr=VelRepr.Inertial)\n",
"L_v_WL = js.link.velocity(\n",
" model=model, data=data, link_index=link_index, output_vel_repr=VelRepr.Body\n",
")\n",
"LW_v_WL = js.link.velocity(\n",
" model=model, data=data, link_index=link_index, output_vel_repr=VelRepr.Mixed\n",
")\n",
"W_v_WL = js.link.velocity(\n",
" model=model, data=data, link_index=link_index, output_vel_repr=VelRepr.Inertial\n",
")\n",
"\n",
"print(f\"Body-fixed velocity L_v_WL={L_v_WL}\")\n",
"print(f\"Mixed velocity: LW_v_WL={LW_v_WL}\")\n",
Expand All @@ -395,17 +403,21 @@
"# the velocity representation of ν, and an output velocity representation that\n",
"# corresponds to the velocity representation of the desired 6D velocity.\n",
"\n",
"# You can use the following context manager to easily switch between representations.\n",
"with data.switch_velocity_representation(VelRepr.Body):\n",
"\n",
" # Body-fixed generalized velocity.\n",
" B_ν = data.generalized_velocity\n",
"# You can set the output velocity representation of quantities depending\n",
"# on the velocity representation stored in data by passing an argument\n",
"# to the function, as shown below.\n",
"# Body-fixed generalized velocity.\n",
"B_ν = data.generalized_velocity(output_representation=VelRepr.Body)\n",
"\n",
" # Free-floating Jacobian accepting a body-fixed generalized velocity and\n",
" # returning an inertial-fixed link velocity.\n",
" W_J_WL_B = js.link.jacobian(\n",
" model=model, data=data, link_index=link_index, output_vel_repr=VelRepr.Inertial\n",
" )\n",
"# Free-floating Jacobian accepting a body-fixed generalized velocity and\n",
"# returning an inertial-fixed link velocity.\n",
"W_J_WL_B = js.link.jacobian(\n",
" model=model,\n",
" data=data,\n",
" link_index=link_index,\n",
" input_representation=VelRepr.Body,\n",
" output_vel_repr=VelRepr.Inertial,\n",
")\n",
"\n",
"# Now the following relation should hold.\n",
"assert jnp.allclose(W_v_WL, W_J_WL_B @ B_ν)"
Expand Down Expand Up @@ -455,9 +467,15 @@
"# @title Frame 6D Velocity\n",
"\n",
"# JaxSim allows to select the so-called representation of the frame velocity.\n",
"F_v_WF = js.frame.velocity(model=model, data=data, frame_index=frame_index, output_vel_repr=VelRepr.Body)\n",
"FW_v_WF = js.frame.velocity(model=model, data=data, frame_index=frame_index, output_vel_repr=VelRepr.Mixed)\n",
"W_v_WF = js.frame.velocity(model=model, data=data, frame_index=frame_index, output_vel_repr=VelRepr.Inertial)\n",
"F_v_WF = js.frame.velocity(\n",
" model=model, data=data, frame_index=frame_index, output_vel_repr=VelRepr.Body\n",
")\n",
"FW_v_WF = js.frame.velocity(\n",
" model=model, data=data, frame_index=frame_index, output_vel_repr=VelRepr.Mixed\n",
")\n",
"W_v_WF = js.frame.velocity(\n",
" model=model, data=data, frame_index=frame_index, output_vel_repr=VelRepr.Inertial\n",
")\n",
"\n",
"print(f\"Body-fixed velocity F_v_WF={F_v_WF}\")\n",
"print(f\"Mixed velocity: FW_v_WF={FW_v_WF}\")\n",
Expand All @@ -468,17 +486,21 @@
"# the velocity representation of ν, and an output velocity representation that\n",
"# corresponds to the velocity representation of the desired 6D velocity.\n",
"\n",
"# You can use the following context manager to easily switch between representations.\n",
"with data.switch_velocity_representation(VelRepr.Body):\n",
"# You can pass the output representation to getters of quantities depending\n",
"# on the velocity representation stored in data by passing an argument.\n",
"\n",
" # Body-fixed generalized velocity.\n",
" B_ν = data.generalized_velocity\n",
"# Body-fixed generalized velocity.\n",
"B_ν = data.generalized_velocity(VelRepr.Body)\n",
"\n",
" # Free-floating Jacobian accepting a body-fixed generalized velocity and\n",
" # returning an inertial-fixed link velocity.\n",
" W_J_WF_B = js.frame.jacobian(\n",
" model=model, data=data, frame_index=frame_index, output_vel_repr=VelRepr.Inertial\n",
" )\n",
"# Free-floating Jacobian accepting a body-fixed generalized velocity and\n",
"# returning an inertial-fixed link velocity.\n",
"W_J_WF_B = js.frame.jacobian(\n",
" model=model,\n",
" data=data,\n",
" frame_index=frame_index,\n",
" input_representation=VelRepr.Body,\n",
" output_vel_repr=VelRepr.Inertial,\n",
")\n",
"\n",
"# Now the following relation should hold.\n",
"assert jnp.allclose(W_v_WF, W_J_WF_B @ B_ν)"
Expand Down Expand Up @@ -662,7 +684,7 @@
" joint_accelerations=s̈,\n",
" # To check that f_B works, let's remove the force applied\n",
" # to the base link from the link forces.\n",
" link_forces=f_L.at[0].set(jnp.zeros(6))\n",
" link_forces=f_L.at[0].set(jnp.zeros(6)),\n",
")\n",
"\n",
"print(f\"f_B: shape={f_B.shape}\")\n",
Expand Down Expand Up @@ -825,30 +847,27 @@
},
"outputs": [],
"source": [
"with (\n",
" data.switch_velocity_representation(VelRepr.Mixed),\n",
" references.switch_velocity_representation(VelRepr.Mixed),\n",
"):\n",
"\n",
" # Compute the mixed generalized velocity.\n",
" BW_ν = data.generalized_velocity\n",
"\n",
" # Compute the mixed generalized acceleration.\n",
" BW_ν̇ = jnp.hstack(\n",
" js.model.forward_dynamics(\n",
" model=model,\n",
" data=data,\n",
" link_forces=references.link_forces(model=model, data=data),\n",
" joint_forces=references.joint_force_references(model=model),\n",
" )\n",
"# Compute the mixed generalized velocity.\n",
"BW_ν = data.generalized_velocity()\n",
"\n",
"# Compute the mixed generalized acceleration.\n",
"BW_ν̇ = jnp.hstack(\n",
" js.model.forward_dynamics(\n",
" model=model,\n",
" data=data,\n",
" link_forces=references.link_forces(\n",
" model=model, data=data, output_representation=VelRepr.Mixed\n",
" ),\n",
" joint_forces=references.joint_force_references(model=model),\n",
" )\n",
")\n",
"\n",
" # Compute the mass matrix in mixed representation.\n",
" BW_M = js.model.free_floating_mass_matrix(model=model, data=data)\n",
"# Compute the mass matrix in mixed representation.\n",
"BW_M = js.model.free_floating_mass_matrix(model=model, data=data)\n",
"\n",
" # Compute the contact Jacobian and its derivative.\n",
" Jl_WC = js.contact.jacobian(model=model, data=data)[:, 0:3, :]\n",
" J̇l_WC = js.contact.jacobian_derivative(model=model, data=data)[:, 0:3, :]\n",
"# Compute the contact Jacobian and its derivative.\n",
"Jl_WC = js.contact.jacobian(model=model, data=data)[:, 0:3, :]\n",
"J̇l_WC = js.contact.jacobian_derivative(model=model, data=data)[:, 0:3, :]\n",
"\n",
"# Compute the Delassus matrix.\n",
"Ψ = jnp.vstack(Jl_WC) @ jnp.linalg.lstsq(BW_M, jnp.vstack(Jl_WC).T)[0]\n",
Expand All @@ -860,9 +879,8 @@
"print(f\"W_H_C: shape={W_H_C.shape}\")\n",
"\n",
"# Compute the linear velocity of the collidable points.\n",
"with data.switch_velocity_representation(VelRepr.Mixed):\n",
" W_ṗ_B = js.contact.collidable_point_velocities(model=model, data=data)[:, 0:3]\n",
" print(f\"W_ṗ_B: shape={W_ṗ_B.shape}\")\n",
"W_ṗ_B = js.contact.collidable_point_velocities(model=model, data=data)[:, 0:3]\n",
"print(f\"W_ṗ_B: shape={W_ṗ_B.shape}\")\n",
"\n",
"# Compute the linear acceleration of the collidable points.\n",
"W_p̈_C = 0\n",
Expand Down
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