diff --git a/python/LQR.ipynb b/python/LQR.ipynb
index adee43ed..89767ac9 100644
--- a/python/LQR.ipynb
+++ b/python/LQR.ipynb
@@ -494,10 +494,10 @@
     "actuator_moment = np.zeros((model.nu, model.nv))\n",
     "mujoco.mju_sparse2dense(\n",
     "    actuator_moment,\n",
-    "    data.actuator_moment,\n",
+    "    data.actuator_moment.reshape(-1),\n",
     "    data.moment_rownnz,\n",
     "    data.moment_rowadr,\n",
-    "    data.moment_colind,\n",
+    "    data.moment_colind.reshape(-1),\n",
     ")\n",
     "ctrl0 = np.atleast_2d(qfrc0) @ np.linalg.pinv(actuator_moment)\n",
     "ctrl0 = ctrl0.flatten()  # Save the ctrl setpoint.\n",