PostureTask: Match implementation and documentation formula

CHANGELOG.md

@@ -28,6 +28,7 @@ All notable changes to this project will be documented in this file.
 
 ### Fixed
 
+- PostureTask: Match implementation and documentation formula
 - Fix broken documentation links
 
 ### Removed

pink/tasks/damping_task.py

@@ -20,8 +20,9 @@ class DampingTask(PostureTask):
     The word "damping" is used here by analogy with forces that fight against
     motion, and bring the robot to a rest if nothing else drives it.
 
-    The damping task is implemented as a special case of the posture task where
-    the gain $\alpha$ is zero.
+    Note:
+        The damping task is implemented as a special case of the posture task
+        where the gain $\alpha$ is zero.
     """
 
     def __init__(self, cost: float, lm_damping: float = 0.0) -> None:

pink/tasks/posture_task.py

@@ -98,8 +98,8 @@ def compute_error(self, configuration: Configuration) -> np.ndarray:
         _, nv = get_root_joint_dim(configuration.model)
         return pin.difference(
             configuration.model,
-            configuration.q,
             self.target_q,
+            configuration.q,
         )[nv:]
 
     def compute_jacobian(self, configuration: Configuration) -> np.ndarray:
@@ -122,7 +122,7 @@ def compute_jacobian(self, configuration: Configuration) -> np.ndarray:
             Posture task Jacobian :math:`J(q)`.
         """
         _, nv = get_root_joint_dim(configuration.model)
-        return -configuration.tangent.eye[nv:, :]
+        return configuration.tangent.eye[nv:, :]
 
     def __repr__(self):
         """Human-readable representation of the task."""