NotImplementedError: rne_postconstraint not implemented with equality constraints: connect, weld.

[HuNingHe]

Intro

I get error:

Traceback (most recent call last):
File "/home/zy/a2_model/model/xml/romela/test.py", line 16, in
mjx_model = mjx.put_model(mj_model)
^^^^^^^^^^^^^^^^^^^^^^^
File "/home/zy/miniconda3/envs/mujoco_playground/lib/python3.12/site-packages/mujoco/mjx/_src/io.py", line 160, in put_model
raise NotImplementedError(
NotImplementedError: rne_postconstraint not implemented with equality constraints: connect, weld.

My setup

When I run code below:
mujoco>3.0.1

import mujoco
from mujoco import mjx
import os

script_dir = os.path.dirname(os.path.abspath(__file__))
xml = script_dir + "/romela_scene.xml"
print("xml path:", xml)

mj_model = mujoco.MjModel.from_xml_path(xml)
mj_data = mujoco.MjData(mj_model)
renderer = mujoco.Renderer(mj_model)

mjx_model = mjx.put_model(mj_model)
mjx_data = mjx.put_data(mj_model, mj_data)

print(mj_data.qpos, type(mj_data.qpos))
print(mjx_data.qpos, type(mjx_data.qpos), mjx_data.qpos.devices())

this xml works fine in mujoco

My question

how to add equality constraint in mjx

Minimal model and/or code that explain my question

If you encountered the issue in a complex model, please simplify it as much as possible (while still reproducing the issue).

Model:

minimal XML

<mujoco>
  <worldbody>
    <light pos="0 0 1"/>
    <geom type="sphere" size="1" rgba="1 0 0 1"/>
  </worldbody>
</mujoco>

Code:

import mujoco
import mediapy as media
model = mujoco.MjModel.from_xml_string(xml)
data = mujoco.MjData(model)

with mujoco.Renderer(model) as renderer:
  mujoco.mj_forward(model, data)
  renderer.update_scene(data)

  media.show_image(renderer.render())

Confirmations

• I searched the latest documentation thoroughly before posting.
• I searched previous Issues and Discussions, I am certain this has not been raised before.