Exception "RuntimeError: generator raised StopIteration" with Python3.7 about ikpy HOT 7 CLOSED

Good catch @cjlux !

Actually this function seems deprecated and should be removed (seems it's not used anywhere).

In which context did you use it?

from ikpy.

We (Yoan Mollard, Thibault Desprez and myself) are presently updating the raspoppyfication process (installing Poppy configuration on a RPi4 under raspbian buster) : the IKpy module is used at start-up by the robot "Ergo Junior" and I found also this bug when using IKpy for the robot "Poppy Torso" to make the robot catch objects recognized by tits camera.

from ikpy.

sorry closing was accidental...

from ikpy.

In order to use URDF, the function get_urdf_parameters should be used instead.

from ikpy.

On the other hand, if you explicitly need it, we can move it to a "deprecated" module (and fix the original issue), instead of just removing it.

from ikpy.

After investigation I found this : the function get_chain_from_joints defined in the file URDF_utils.py is called at line 25 of the file ik.py from the module pypot.creature :
25 chain_elements = get_chain_from_joints(poppy.urdf_file, [m.name for m in motors])
and the liste chain_elements contains for example :
['base', 'abs_z', 'spine', 'bust_y', 'bust_motors', 'bust_x', 'chest', 'l_shoulder_y', 'l_shoulder', 'l_shoulder_x', 'l_shoulder_motor', 'l_arm_z', 'l_upper_arm', 'l_elbow_y']

Some lines later in the file ik.py the list chain_elements is given as argument to the call :

30         chain = cls.from_urdf_file(poppy.urdf_file,
31                                    base_elements=chain_elements,
32                                    last_link_vector=tip,
33                                    active_links_mask=activ)`

and the function from_urdf_file (in the file chain.py from the module IKpy) calls itself the function get_urdf_parameters with among others the argument base_elements=chain_elements...

So if you plan to deprecate the function get_chain_from_joints the question is : how to generate the list chain_elements ?
Or a related question is : what kind of information in details is required for the argument base_elements of the get_urdf_parameters function ?

from ikpy.

Actually this function seems useful in the way it's used, since it permits to get a list of links+joints from a list of joints.

And this use-case can be appear in the pypot creatures context: Since IKp's URDF parser requires a list of links+joints, and pypot works with a list of joints, this function makes the link between the two

from ikpy.