Memory Leak with multiple DH_robot initializations

[shubh-arm]

Describe the bug
In a loop I am generating a myDH_robot from some DH parameters, providing q_targets and calculating the forward kinematics and the jacobian of these q_targets. There are roughly 500,000 targets that are provided and then analyzed using the functions myDH_robot.fkine and myDH_robot.jacob0 the generated values are then stored. Afterwards the generated robot is deleted along with any arrays that have values stored to them. Furthermore gc.collect is run to ensure appropriate removal of items.

This loop incrementally demands more memory at every iteration and by about iteration 16 the loop has demanded nearly 100% of the systems memory resulting in a crash.

After checked through my implementation for a potential leak I have determined by tracemalloc that the leak is to do with ET.py, ETS.py, and fknm.cpp, which to my understanding are responsible for the initialization of DH_robots. My understanding is that in my unique implementation where I am generating, analyzing, and then discarding the DH_robot results in the DH_robot being removed in the scope of my script. However it does not remove it from the scope of the toolbox.

tracemalloc pointed to line 117 in ET.py and line 62 in ETS.py

when looking through ET.py it appears that in my case the C objects reference is lost, but the object is not deleted which then results in the accumulation through the loop. This appears to track when following to the *ET_init PyObject in fknm.cpp where the pointer might be getting lost but not deleted

Version information

Did you install from PyPI or GitHub?
installed from github on Commit 2a8111b

Robotics Toolbox depends heavily on two other packages: Swift (3D graphics) and SpatialMath toolbox (underpinning maths utilities). If you think your issue is related to these, then please answer the questions above for them.

No issues related to swift or spatialmath toolbox

To Reproduce
Create a DH_robot class that pulls from an array of DH_parameters. Create a loop that generates unique parameters which is then passed to the generated class. From there using the functions of the class for a loop of q_targets.

Expected behavior
Memory usage between loop instances remains relatively stable

Screenshots

Environment (please complete the following information):

• Ubuntu 22.04

Additional context
Let me know if there is anything I can help clarify