Add aloha + improve readme

lerobot/common/datasets/pusht.py

@@ -8,7 +8,6 @@ import pymunk
 import torch
 import torchrl
 import tqdm
-from huggingface_hub import snapshot_download
 from tensordict import TensorDict
 from torchrl.data.replay_buffers.samplers import SliceSampler
 from torchrl.data.replay_buffers.storages import TensorStorage
@@ -112,12 +111,8 @@ class PushtExperienceReplay(AbstractExperienceReplay):
             transform=transform,
         )
 
-    def _download_and_preproc(self):
-        snapshot_download(repo_id="cadene/pusht", local_dir=self.data_dir)
-        return TensorStorage(TensorDict.load_memmap(self.data_dir))
-
     def _download_and_preproc_obsolete(self):
-        raw_dir = self.data_dir.parent / f"{self.data_dir.name}_raw"
+        raw_dir = Path(self.root) / f"{self.dataset_id}_raw"
         zarr_path = (raw_dir / PUSHT_ZARR).resolve()
         if not zarr_path.is_dir():
             raw_dir.mkdir(parents=True, exist_ok=True)
@@ -213,7 +208,7 @@ class PushtExperienceReplay(AbstractExperienceReplay):
 
             if episode_id == 0:
                 # hack to initialize tensordict data structure to store episodes
-                td_data = ep_td[0].expand(total_frames).memmap_like(self.data_dir)
+                td_data = ep_td[0].expand(total_frames).memmap_like(Path(self.root) / f"{self.dataset_id}")
 
             td_data[idxtd : idxtd + len(ep_td)] = ep_td