deactivate robot jacobian calculation

Author: baggepinnen

docs/src/examples/robot.md

@@ -130,13 +130,14 @@ fkine(prob.u0, prob.p, 0)
 !!! note
     The function `fkine` above takes the full state of the robot model, as opposed to only the joint angles.
 
-### Jacobian
-We can compute the Jacobian ``J`` of the forward-kinematics function using the package ForwardDiff (this Jacobian is often referred to as the _analytical Jacobian_, which in the 6DOF case is different from the _geometrical Jacobian_ that is used in the relation ``v = J\dot{q}``). The Jacobian of the end-effector positional coordinates will be a 3×36 matrix, since we have 36-dimensional state of the robot after simplification. Since the end-effector coordinates do not depend on all the state variables, we may ask which variables it depends on by finding non-zero columns of ``J``
-```@example robot
-using ModelingToolkit.ForwardDiff
-J = ForwardDiff.jacobian(x->fkine(x, prob.p, 0), prob.u0)
-nonzero_inds = findall(any(!iszero, J, dims=1)[:])
-unknowns(ssys)[nonzero_inds]
-```
-We see that the end-effector position depends on all mechanical angles except for the last one, which is expected since the end-effector origin is on the axis of rotation of joint 6. 
-
+```@setup
+# ### Jacobian # Temporarily deactivated
+# We can compute the Jacobian ``J`` of the forward-kinematics function using the package ForwardDiff (this Jacobian is often referred to as the _analytical Jacobian_, which in the 6DOF case is different from the _geometrical Jacobian_ that is used in the relation ``v = J\dot{q}``). The Jacobian of the end-effector positional coordinates will be a 3×36 matrix, since we have 36-dimensional state of the robot after simplification. Since the end-effector coordinates do not depend on all the state variables, we may ask which variables it depends on by finding non-zero columns of ``J``
+# ```@example robot
+# using ModelingToolkit.ForwardDiff
+# J = ForwardDiff.jacobian(x->fkine(x, prob.p, 0), prob.u0)
+# nonzero_inds = findall(any(!iszero, J, dims=1)[:])
+# unknowns(ssys)[nonzero_inds]
+# ```
+# We see that the end-effector position depends on all mechanical angles except for the last one, which is expected since the end-effector origin is on the axis of rotation of joint 6. 
+```