[python/dynamics] Fix bug making 'Trajectory.get' extremely inefficient.

python/gym_jiminy/common/gym_jiminy/common/utils/spaces.py

@@ -52,9 +52,6 @@ def _array_clip(value: np.ndarray,
     :param low: Optional lower bound.
     :param high: Optional upper bound.
     """
-    # Note that in-place clipping is actually slower than out-of-place in
-    # Numba when 'fastmath' compilation flag is set.
-
     # Short circuit if there is neither low or high bounds
     if low is None and high is None:
         return value.copy()

python/jiminy_py/src/jiminy_py/dynamics.py

@@ -215,7 +215,7 @@ def __init__(self,
         self._t_prev = 0.0
         self._index_prev = 1
 
-        # List of optional state fields that are provided
+        # List of optional state fields that have been specified.
         # Note that looking for keys in such a small set is not worth the
         # hassle of using Python `set`, which breaks ordering and index access.
         fields_: List[str] = []
@@ -227,7 +227,7 @@ def __init__(self,
                         raise ValueError(
                             "The state information being set must be the same "
                             "for all the timesteps of a given trajectory.")
-                else:
+                elif field not in fields_:
                     fields_.append(field)
         self._fields = tuple(fields_)
 
@@ -286,10 +286,11 @@ def time_interval(self) -> Tuple[float, float]:
 
         It raises an exception if no data is available.
         """
-        if not self.has_data:
+        try:
+            return (self._times[0], self._times[-1])
+        except IndexError as e:
             raise RuntimeError(
-                "State sequence is empty. Time interval undefined.")
-        return (self._times[0], self._times[-1])
+                "State sequence is empty. Time interval undefined.") from e
 
     def get(self, t: float, mode: TrajectoryTimeMode = 'raise') -> State:
         """Query the state at a given timestamp.
@@ -311,20 +312,19 @@ def get(self, t: float, mode: TrajectoryTimeMode = 'raise') -> State:
         """
         # pylint: disable=possibly-used-before-assignment
 
-        # Raise exception if state sequence is empty
-        if not self.has_data:
-            raise RuntimeError(
-                "State sequence is empty. Impossible to interpolate data.")
-
         # Backup the original query time
         t_orig = t
 
         # Handling of the desired mode
         n_steps = 0.0
-        t_start, t_end = self.time_interval
+        try:
+            t_start, t_end = self._times[0], self._times[-1]
+        except IndexError as e:
+            raise RuntimeError(
+                "State sequence is empty. Impossible to interpolate data.")
         if mode == "raise":
             if t - t_end > TRAJ_INTERP_TOL or t_start - t > TRAJ_INTERP_TOL:
-                raise RuntimeError("Time is out-of-range.")
+                raise RuntimeError("Query time out-of-range.")
         elif mode == "wrap":
             if t_end > t_start:
                 n_steps, t_rel = divmod(t - t_start, t_end - t_start)
@@ -365,26 +365,26 @@ def get(self, t: float, mode: TrajectoryTimeMode = 'raise') -> State:
         else:
             position = pin.interpolate(
                 self._pinocchio_model, s_left.q, s_right.q, alpha)
-        data = {"q": position}
+        state = dict(t=t_orig, q=position)
         for field in self._fields:
             value_left = getattr(s_left, field)
             if return_left:
-                data[field] = value_left.copy()
+                state[field] = value_left.copy()
                 continue
             value_right = getattr(s_right, field)
             if return_right:
-                data[field] = value_right.copy()
+                state[field] = value_right.copy()
             else:
-                data[field] = value_left + alpha * (value_right - value_left)
+                state[field] = value_left + alpha * (value_right - value_left)
 
         # Perform odometry if time is wrapping
         if self._stride_offset_log6 is not None and n_steps:
             stride_offset = pin.exp6(n_steps * self._stride_offset_log6)
             ff_xyzquat = stride_offset * pin.XYZQUATToSE3(position[:7])
             position[:7] = pin.SE3ToXYZQUAT(ff_xyzquat)
 
-        # Return state instances bundling all data
-        return State(t=t_orig, **data)
+        # Return State object
+        return State(**state)
 
 
 # #####################################################################