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lerobot/lerobot/common/datasets/_diffusion_policy_replay_buffer.py
2024-04-16 17:24:25 +00:00

620 lines
20 KiB
Python

"""Helper code for loading PushT dataset from Diffusion Policy (https://diffusion-policy.cs.columbia.edu/)
Copied from the original Diffusion Policy repository and used in our `download_and_upload_dataset.py` script.
"""
from __future__ import annotations
import math
import numbers
import os
from functools import cached_property
import numcodecs
import numpy as np
import zarr
def check_chunks_compatible(chunks: tuple, shape: tuple):
assert len(shape) == len(chunks)
for c in chunks:
assert isinstance(c, numbers.Integral)
assert c > 0
def rechunk_recompress_array(group, name, chunks=None, chunk_length=None, compressor=None, tmp_key="_temp"):
old_arr = group[name]
if chunks is None:
chunks = (chunk_length,) + old_arr.chunks[1:] if chunk_length is not None else old_arr.chunks
check_chunks_compatible(chunks, old_arr.shape)
if compressor is None:
compressor = old_arr.compressor
if (chunks == old_arr.chunks) and (compressor == old_arr.compressor):
# no change
return old_arr
# rechunk recompress
group.move(name, tmp_key)
old_arr = group[tmp_key]
n_copied, n_skipped, n_bytes_copied = zarr.copy(
source=old_arr,
dest=group,
name=name,
chunks=chunks,
compressor=compressor,
)
del group[tmp_key]
arr = group[name]
return arr
def get_optimal_chunks(shape, dtype, target_chunk_bytes=2e6, max_chunk_length=None):
"""
Common shapes
T,D
T,N,D
T,H,W,C
T,N,H,W,C
"""
itemsize = np.dtype(dtype).itemsize
# reversed
rshape = list(shape[::-1])
if max_chunk_length is not None:
rshape[-1] = int(max_chunk_length)
split_idx = len(shape) - 1
for i in range(len(shape) - 1):
this_chunk_bytes = itemsize * np.prod(rshape[:i])
next_chunk_bytes = itemsize * np.prod(rshape[: i + 1])
if this_chunk_bytes <= target_chunk_bytes and next_chunk_bytes > target_chunk_bytes:
split_idx = i
rchunks = rshape[:split_idx]
item_chunk_bytes = itemsize * np.prod(rshape[:split_idx])
this_max_chunk_length = rshape[split_idx]
next_chunk_length = min(this_max_chunk_length, math.ceil(target_chunk_bytes / item_chunk_bytes))
rchunks.append(next_chunk_length)
len_diff = len(shape) - len(rchunks)
rchunks.extend([1] * len_diff)
chunks = tuple(rchunks[::-1])
# print(np.prod(chunks) * itemsize / target_chunk_bytes)
return chunks
class ReplayBuffer:
"""
Zarr-based temporal datastructure.
Assumes first dimension to be time. Only chunk in time dimension.
"""
def __init__(self, root: zarr.Group | dict[str, dict]):
"""
Dummy constructor. Use copy_from* and create_from* class methods instead.
"""
assert "data" in root
assert "meta" in root
assert "episode_ends" in root["meta"]
for value in root["data"].values():
assert value.shape[0] == root["meta"]["episode_ends"][-1]
self.root = root
# ============= create constructors ===============
@classmethod
def create_empty_zarr(cls, storage=None, root=None):
if root is None:
if storage is None:
storage = zarr.MemoryStore()
root = zarr.group(store=storage)
root.require_group("data", overwrite=False)
meta = root.require_group("meta", overwrite=False)
if "episode_ends" not in meta:
meta.zeros("episode_ends", shape=(0,), dtype=np.int64, compressor=None, overwrite=False)
return cls(root=root)
@classmethod
def create_empty_numpy(cls):
root = {"data": {}, "meta": {"episode_ends": np.zeros((0,), dtype=np.int64)}}
return cls(root=root)
@classmethod
def create_from_group(cls, group, **kwargs):
if "data" not in group:
# create from stratch
buffer = cls.create_empty_zarr(root=group, **kwargs)
else:
# already exist
buffer = cls(root=group, **kwargs)
return buffer
@classmethod
def create_from_path(cls, zarr_path, mode="r", **kwargs):
"""
Open a on-disk zarr directly (for dataset larger than memory).
Slower.
"""
group = zarr.open(os.path.expanduser(zarr_path), mode)
return cls.create_from_group(group, **kwargs)
# ============= copy constructors ===============
@classmethod
def copy_from_store(
cls,
src_store,
store=None,
keys=None,
chunks: dict[str, tuple] | None = None,
compressors: dict | str | numcodecs.abc.Codec | None = None,
if_exists="replace",
**kwargs,
):
"""
Load to memory.
"""
src_root = zarr.group(src_store)
if chunks is None:
chunks = {}
if compressors is None:
compressors = {}
root = None
if store is None:
# numpy backend
meta = {}
for key, value in src_root["meta"].items():
if len(value.shape) == 0:
meta[key] = np.array(value)
else:
meta[key] = value[:]
if keys is None:
keys = src_root["data"].keys()
data = {}
for key in keys:
arr = src_root["data"][key]
data[key] = arr[:]
root = {"meta": meta, "data": data}
else:
root = zarr.group(store=store)
# copy without recompression
n_copied, n_skipped, n_bytes_copied = zarr.copy_store(
source=src_store, dest=store, source_path="/meta", dest_path="/meta", if_exists=if_exists
)
data_group = root.create_group("data", overwrite=True)
if keys is None:
keys = src_root["data"].keys()
for key in keys:
value = src_root["data"][key]
cks = cls._resolve_array_chunks(chunks=chunks, key=key, array=value)
cpr = cls._resolve_array_compressor(compressors=compressors, key=key, array=value)
if cks == value.chunks and cpr == value.compressor:
# copy without recompression
this_path = "/data/" + key
n_copied, n_skipped, n_bytes_copied = zarr.copy_store(
source=src_store,
dest=store,
source_path=this_path,
dest_path=this_path,
if_exists=if_exists,
)
else:
# copy with recompression
n_copied, n_skipped, n_bytes_copied = zarr.copy(
source=value,
dest=data_group,
name=key,
chunks=cks,
compressor=cpr,
if_exists=if_exists,
)
buffer = cls(root=root)
return buffer
@classmethod
def copy_from_path(
cls,
zarr_path,
backend=None,
store=None,
keys=None,
chunks: dict[str, tuple] | None = None,
compressors: dict | str | numcodecs.abc.Codec | None = None,
if_exists="replace",
**kwargs,
):
"""
Copy a on-disk zarr to in-memory compressed.
Recommended
"""
if chunks is None:
chunks = {}
if compressors is None:
compressors = {}
if backend == "numpy":
print("backend argument is deprecated!")
store = None
group = zarr.open(os.path.expanduser(zarr_path), "r")
return cls.copy_from_store(
src_store=group.store,
store=store,
keys=keys,
chunks=chunks,
compressors=compressors,
if_exists=if_exists,
**kwargs,
)
# ============= save methods ===============
def save_to_store(
self,
store,
chunks: dict[str, tuple] | None = None,
compressors: str | numcodecs.abc.Codec | dict | None = None,
if_exists="replace",
**kwargs,
):
root = zarr.group(store)
if chunks is None:
chunks = {}
if compressors is None:
compressors = {}
if self.backend == "zarr":
# recompression free copy
n_copied, n_skipped, n_bytes_copied = zarr.copy_store(
source=self.root.store,
dest=store,
source_path="/meta",
dest_path="/meta",
if_exists=if_exists,
)
else:
meta_group = root.create_group("meta", overwrite=True)
# save meta, no chunking
for key, value in self.root["meta"].items():
_ = meta_group.array(name=key, data=value, shape=value.shape, chunks=value.shape)
# save data, chunk
data_group = root.create_group("data", overwrite=True)
for key, value in self.root["data"].items():
cks = self._resolve_array_chunks(chunks=chunks, key=key, array=value)
cpr = self._resolve_array_compressor(compressors=compressors, key=key, array=value)
if isinstance(value, zarr.Array):
if cks == value.chunks and cpr == value.compressor:
# copy without recompression
this_path = "/data/" + key
n_copied, n_skipped, n_bytes_copied = zarr.copy_store(
source=self.root.store,
dest=store,
source_path=this_path,
dest_path=this_path,
if_exists=if_exists,
)
else:
# copy with recompression
n_copied, n_skipped, n_bytes_copied = zarr.copy(
source=value,
dest=data_group,
name=key,
chunks=cks,
compressor=cpr,
if_exists=if_exists,
)
else:
# numpy
_ = data_group.array(name=key, data=value, chunks=cks, compressor=cpr)
return store
def save_to_path(
self,
zarr_path,
chunks: dict[str, tuple] | None = None,
compressors: str | numcodecs.abc.Codec | dict | None = None,
if_exists="replace",
**kwargs,
):
if chunks is None:
chunks = {}
if compressors is None:
compressors = {}
store = zarr.DirectoryStore(os.path.expanduser(zarr_path))
return self.save_to_store(
store, chunks=chunks, compressors=compressors, if_exists=if_exists, **kwargs
)
@staticmethod
def resolve_compressor(compressor="default"):
if compressor == "default":
compressor = numcodecs.Blosc(cname="lz4", clevel=5, shuffle=numcodecs.Blosc.NOSHUFFLE)
elif compressor == "disk":
compressor = numcodecs.Blosc("zstd", clevel=5, shuffle=numcodecs.Blosc.BITSHUFFLE)
return compressor
@classmethod
def _resolve_array_compressor(cls, compressors: dict | str | numcodecs.abc.Codec, key, array):
# allows compressor to be explicitly set to None
cpr = "nil"
if isinstance(compressors, dict):
if key in compressors:
cpr = cls.resolve_compressor(compressors[key])
elif isinstance(array, zarr.Array):
cpr = array.compressor
else:
cpr = cls.resolve_compressor(compressors)
# backup default
if cpr == "nil":
cpr = cls.resolve_compressor("default")
return cpr
@classmethod
def _resolve_array_chunks(cls, chunks: dict | tuple, key, array):
cks = None
if isinstance(chunks, dict):
if key in chunks:
cks = chunks[key]
elif isinstance(array, zarr.Array):
cks = array.chunks
elif isinstance(chunks, tuple):
cks = chunks
else:
raise TypeError(f"Unsupported chunks type {type(chunks)}")
# backup default
if cks is None:
cks = get_optimal_chunks(shape=array.shape, dtype=array.dtype)
# check
check_chunks_compatible(chunks=cks, shape=array.shape)
return cks
# ============= properties =================
@cached_property
def data(self):
return self.root["data"]
@cached_property
def meta(self):
return self.root["meta"]
def update_meta(self, data):
# sanitize data
np_data = {}
for key, value in data.items():
if isinstance(value, np.ndarray):
np_data[key] = value
else:
arr = np.array(value)
if arr.dtype == object:
raise TypeError(f"Invalid value type {type(value)}")
np_data[key] = arr
meta_group = self.meta
if self.backend == "zarr":
for key, value in np_data.items():
_ = meta_group.array(
name=key, data=value, shape=value.shape, chunks=value.shape, overwrite=True
)
else:
meta_group.update(np_data)
return meta_group
@property
def episode_ends(self):
return self.meta["episode_ends"]
def get_episode_idxs(self):
import numba
numba.jit(nopython=True)
def _get_episode_idxs(episode_ends):
result = np.zeros((episode_ends[-1],), dtype=np.int64)
for i in range(len(episode_ends)):
start = 0
if i > 0:
start = episode_ends[i - 1]
end = episode_ends[i]
for idx in range(start, end):
result[idx] = i
return result
return _get_episode_idxs(self.episode_ends)
@property
def backend(self):
backend = "numpy"
if isinstance(self.root, zarr.Group):
backend = "zarr"
return backend
# =========== dict-like API ==============
def __repr__(self) -> str:
if self.backend == "zarr":
return str(self.root.tree())
else:
return super().__repr__()
def keys(self):
return self.data.keys()
def values(self):
return self.data.values()
def items(self):
return self.data.items()
def __getitem__(self, key):
return self.data[key]
def __contains__(self, key):
return key in self.data
# =========== our API ==============
@property
def n_steps(self):
if len(self.episode_ends) == 0:
return 0
return self.episode_ends[-1]
@property
def n_episodes(self):
return len(self.episode_ends)
@property
def chunk_size(self):
if self.backend == "zarr":
return next(iter(self.data.arrays()))[-1].chunks[0]
return None
@property
def episode_lengths(self):
ends = self.episode_ends[:]
ends = np.insert(ends, 0, 0)
lengths = np.diff(ends)
return lengths
def add_episode(
self,
data: dict[str, np.ndarray],
chunks: dict[str, tuple] | None = None,
compressors: str | numcodecs.abc.Codec | dict | None = None,
):
if chunks is None:
chunks = {}
if compressors is None:
compressors = {}
assert len(data) > 0
is_zarr = self.backend == "zarr"
curr_len = self.n_steps
episode_length = None
for value in data.values():
assert len(value.shape) >= 1
if episode_length is None:
episode_length = len(value)
else:
assert episode_length == len(value)
new_len = curr_len + episode_length
for key, value in data.items():
new_shape = (new_len,) + value.shape[1:]
# create array
if key not in self.data:
if is_zarr:
cks = self._resolve_array_chunks(chunks=chunks, key=key, array=value)
cpr = self._resolve_array_compressor(compressors=compressors, key=key, array=value)
arr = self.data.zeros(
name=key, shape=new_shape, chunks=cks, dtype=value.dtype, compressor=cpr
)
else:
# copy data to prevent modify
arr = np.zeros(shape=new_shape, dtype=value.dtype)
self.data[key] = arr
else:
arr = self.data[key]
assert value.shape[1:] == arr.shape[1:]
# same method for both zarr and numpy
if is_zarr:
arr.resize(new_shape)
else:
arr.resize(new_shape, refcheck=False)
# copy data
arr[-value.shape[0] :] = value
# append to episode ends
episode_ends = self.episode_ends
if is_zarr:
episode_ends.resize(episode_ends.shape[0] + 1)
else:
episode_ends.resize(episode_ends.shape[0] + 1, refcheck=False)
episode_ends[-1] = new_len
# rechunk
if is_zarr and episode_ends.chunks[0] < episode_ends.shape[0]:
rechunk_recompress_array(self.meta, "episode_ends", chunk_length=int(episode_ends.shape[0] * 1.5))
def drop_episode(self):
is_zarr = self.backend == "zarr"
episode_ends = self.episode_ends[:].copy()
assert len(episode_ends) > 0
start_idx = 0
if len(episode_ends) > 1:
start_idx = episode_ends[-2]
for value in self.data.values():
new_shape = (start_idx,) + value.shape[1:]
if is_zarr:
value.resize(new_shape)
else:
value.resize(new_shape, refcheck=False)
if is_zarr:
self.episode_ends.resize(len(episode_ends) - 1)
else:
self.episode_ends.resize(len(episode_ends) - 1, refcheck=False)
def pop_episode(self):
assert self.n_episodes > 0
episode = self.get_episode(self.n_episodes - 1, copy=True)
self.drop_episode()
return episode
def extend(self, data):
self.add_episode(data)
def get_episode(self, idx, copy=False):
idx = list(range(len(self.episode_ends)))[idx]
start_idx = 0
if idx > 0:
start_idx = self.episode_ends[idx - 1]
end_idx = self.episode_ends[idx]
result = self.get_steps_slice(start_idx, end_idx, copy=copy)
return result
def get_episode_slice(self, idx):
start_idx = 0
if idx > 0:
start_idx = self.episode_ends[idx - 1]
end_idx = self.episode_ends[idx]
return slice(start_idx, end_idx)
def get_steps_slice(self, start, stop, step=None, copy=False):
_slice = slice(start, stop, step)
result = {}
for key, value in self.data.items():
x = value[_slice]
if copy and isinstance(value, np.ndarray):
x = x.copy()
result[key] = x
return result
# =========== chunking =============
def get_chunks(self) -> dict:
assert self.backend == "zarr"
chunks = {}
for key, value in self.data.items():
chunks[key] = value.chunks
return chunks
def set_chunks(self, chunks: dict):
assert self.backend == "zarr"
for key, value in chunks.items():
if key in self.data:
arr = self.data[key]
if value != arr.chunks:
check_chunks_compatible(chunks=value, shape=arr.shape)
rechunk_recompress_array(self.data, key, chunks=value)
def get_compressors(self) -> dict:
assert self.backend == "zarr"
compressors = {}
for key, value in self.data.items():
compressors[key] = value.compressor
return compressors
def set_compressors(self, compressors: dict):
assert self.backend == "zarr"
for key, value in compressors.items():
if key in self.data:
arr = self.data[key]
compressor = self.resolve_compressor(value)
if compressor != arr.compressor:
rechunk_recompress_array(self.data, key, compressor=compressor)