Roll back recent change to mjData.qLD until some issues are resolved.

PiperOrigin-RevId: 724389161
Change-Id: I1b30ab0950ab5c5e611b1c6fc3bf3f42f964939c

mjx/mujoco/mjx/_src/io.py

@@ -368,7 +368,7 @@ def make_data(
         'efc_aref': (nefc, float),
         'efc_force': (nefc, float),
         '_qM_sparse': (m.nM, float),
-        '_qLD_sparse': (m.nC, float),
+        '_qLD_sparse': (m.nM, float),
         '_qLDiagInv_sparse': (m.nv, float),
     }
 

mjx/mujoco/mjx/_src/smooth_test.py

@@ -91,10 +91,7 @@ class SmoothTest(absltest.TestCase):
     _assert_eq(dx._qM_sparse, np.zeros(0), '_qM_sparse')
     # factor_m
     dx = jax.jit(mjx.factor_m)(mx, mjx.put_data(m, d))
-    qLDLegacy = np.zeros(mx.nM)  # pylint:disable=invalid-name
-    for i in range(m.nC):
-      qLDLegacy[d.mapM2C[i]] = d.qLD[i]
-    _assert_eq(qLDLegacy, dx.qLD, 'qLD')
+    _assert_attr_eq(d, dx, 'qLD')
     _assert_attr_eq(d, dx, 'qLDiagInv')
     _assert_eq(dx._qLD_sparse, np.zeros(0), '_qLD_sparse')
     _assert_eq(dx._qLDiagInv_sparse, np.zeros(0), '_qLDiagInv_sparse')

mjx/mujoco/mjx/_src/types.py

@@ -1348,7 +1348,7 @@ class Data(PyTreeNode):
     efc_aref: reference pseudo-acceleration                     (nefc,)
     efc_force: constraint force in constraint space             (nefc,)
     _qM_sparse: qM in sparse representation                     (nM,)
-    _qLD_sparse: qLD in sparse representation                   (nC,)
+    _qLD_sparse: qLD in sparse representation                   (nM,)
     _qLDiagInv_sparse: qLDiagInv in sparse representation       (nv,)
   """  # fmt: skip
   # constant sizes: