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2026-07-13 13:17:40 +08:00

548 lines
19 KiB
Python

from typing import Any, List, Optional, Union
import gymnasium as gym
import numpy as np
import tree # pip install dm_tree
from ray.rllib.utils.annotations import DeveloperAPI
@DeveloperAPI
class BatchedNdArray(np.ndarray):
"""A ndarray-wrapper the usage of which indicates that there a batch dim exists.
This is such that our `batch()` utility can distinguish between having to
stack n individual batch items (each one w/o any batch dim) vs having to
concatenate n already batched items (each one possibly with a different batch
dim, but definitely with some batch dim).
TODO (sven): Maybe replace this by a list-override instead.
"""
def __new__(cls, input_array):
# Use __new__ to create a new instance of our subclass.
obj = np.asarray(input_array).view(cls)
return obj
@DeveloperAPI
def get_original_space(space: gym.Space) -> gym.Space:
"""Returns the original space of a space, if any.
This function recursively traverses the given space and returns the original space
at the very end of the chain.
Args:
space: The space to get the original space for.
Returns:
The original space or the given space itself if no original space is found.
"""
if hasattr(space, "original_space"):
return get_original_space(space.original_space)
else:
return space
@DeveloperAPI
def is_composite_space(space: gym.Space) -> bool:
"""Returns true, if the space is composite.
Note, we follow here the glossary of `gymnasium` by which any spoace
that holds other spaces is defined as being 'composite'.
Args:
space: The space to be checked for being composed of other spaces.
Returns:
True, if the space is composed of other spaces, otherwise False.
"""
if type(space) in [
gym.spaces.Dict,
gym.spaces.Graph,
gym.spaces.Sequence,
gym.spaces.Tuple,
]:
return True
else:
return False
@DeveloperAPI
def flatten_space(space: gym.Space) -> List[gym.Space]:
"""Flattens a gym.Space into its primitive components.
Primitive components are any non Tuple/Dict spaces.
Args:
space: The gym.Space to flatten. This may be any
supported type (including nested Tuples and Dicts).
Returns:
List[gym.Space]: The flattened list of primitive Spaces. This list
does not contain Tuples or Dicts anymore.
"""
def _helper_flatten(space_, return_list):
from ray.rllib.utils.spaces.flexdict import FlexDict
if isinstance(space_, gym.spaces.Tuple):
for s in space_:
_helper_flatten(s, return_list)
elif isinstance(space_, (gym.spaces.Dict, FlexDict)):
for k in sorted(space_.spaces):
_helper_flatten(space_[k], return_list)
else:
return_list.append(space_)
ret = []
_helper_flatten(space, ret)
return ret
@DeveloperAPI
def get_base_struct_from_space(space):
"""Returns a Tuple/Dict Space as native (equally structured) py tuple/dict.
Args:
space: The Space to get the python struct for.
Returns:
Union[dict,tuple,gym.Space]: The struct equivalent to the given Space.
Note that the returned struct still contains all original
"primitive" Spaces (e.g. Box, Discrete).
.. testcode::
:skipif: True
get_base_struct_from_space(Dict({
"a": Box(),
"b": Tuple([Discrete(2), Discrete(3)])
}))
.. testoutput::
dict(a=Box(), b=tuple(Discrete(2), Discrete(3)))
"""
def _helper_struct(space_):
if isinstance(space_, gym.spaces.Tuple):
return tuple(_helper_struct(s) for s in space_)
elif isinstance(space_, gym.spaces.Dict):
return {k: _helper_struct(space_[k]) for k in space_.spaces}
else:
return space_
return _helper_struct(space)
@DeveloperAPI
def get_dummy_batch_for_space(
space: gym.Space,
batch_size: int = 32,
*,
fill_value: Union[float, int, str] = 0.0,
time_size: Optional[int] = None,
time_major: bool = False,
one_hot_discrete: bool = False,
) -> np.ndarray:
"""Returns batched dummy data (using `batch_size`) for the given `space`.
Note: The returned batch will not pass a `space.contains(batch)` test
as an additional batch dimension has to be added at axis 0, unless `batch_size` is
set to 0.
Args:
space: The space to get a dummy batch for.
batch_size: The required batch size (B). Note that this can also
be 0 (only if `time_size` is None!), which will result in a
non-batched sample for the given space (no batch dim).
fill_value: The value to fill the batch with
or "random" for random values.
time_size: If not None, add an optional time axis
of `time_size` size to the returned batch. This time axis might either
be inserted at axis=1 (default) or axis=0, if `time_major` is True.
time_major: If True AND `time_size` is not None, return batch
as shape [T x B x ...], otherwise as [B x T x ...]. If `time_size`
if None, ignore this setting and return [B x ...].
one_hot_discrete: If True, will return one-hot vectors (instead of
int-values) for those sub-components of a (possibly complex) `space`
that are Discrete or MultiDiscrete. Note that in case `fill_value` is 0.0,
this will result in zero-hot vectors (where all slots have a value of 0.0).
Returns:
The dummy batch of size `bqtch_size` matching the given space.
"""
# Complex spaces. Perform recursive calls of this function.
if isinstance(space, (gym.spaces.Dict, gym.spaces.Tuple, dict, tuple)):
base_struct = space
if isinstance(space, (gym.spaces.Dict, gym.spaces.Tuple)):
base_struct = get_base_struct_from_space(space)
return tree.map_structure(
lambda s: get_dummy_batch_for_space(
space=s,
batch_size=batch_size,
fill_value=fill_value,
time_size=time_size,
time_major=time_major,
one_hot_discrete=one_hot_discrete,
),
base_struct,
)
if one_hot_discrete:
if isinstance(space, gym.spaces.Discrete):
space = gym.spaces.Box(0.0, 1.0, (space.n,), np.float32)
elif isinstance(space, gym.spaces.MultiDiscrete):
space = gym.spaces.Box(0.0, 1.0, (np.sum(space.nvec),), np.float32)
# Primitive spaces: Box, Discrete, MultiDiscrete.
# Random values: Use gym's sample() method.
if fill_value == "random":
if time_size is not None:
assert batch_size > 0 and time_size > 0
if time_major:
return np.array(
[
[space.sample() for _ in range(batch_size)]
for t in range(time_size)
],
dtype=space.dtype,
)
else:
return np.array(
[
[space.sample() for t in range(time_size)]
for _ in range(batch_size)
],
dtype=space.dtype,
)
else:
return np.array(
[space.sample() for _ in range(batch_size)]
if batch_size > 0
else space.sample(),
dtype=space.dtype,
)
# Fill value given: Use np.full.
else:
if time_size is not None:
assert batch_size > 0 and time_size > 0
if time_major:
shape = [time_size, batch_size]
else:
shape = [batch_size, time_size]
else:
shape = [batch_size] if batch_size > 0 else []
return np.full(
shape + list(space.shape), fill_value=fill_value, dtype=space.dtype
)
@DeveloperAPI
def flatten_to_single_ndarray(input_):
"""Returns a single np.ndarray given a list/tuple of np.ndarrays.
Args:
input_ (Union[List[np.ndarray], np.ndarray]): The list of ndarrays or
a single ndarray.
Returns:
np.ndarray: The result after concatenating all single arrays in input_.
.. testcode::
:skipif: True
flatten_to_single_ndarray([
np.array([[1.0, 2.0], [3.0, 4.0], [5.0, 6.0]]),
np.array([7, 8, 9]),
])
.. testoutput::
np.array([
1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0
])
"""
# Concatenate complex inputs.
if isinstance(input_, (list, tuple, dict)):
expanded = []
for in_ in tree.flatten(input_):
expanded.append(np.reshape(in_, [-1]))
input_ = np.concatenate(expanded, axis=0).flatten()
return input_
@DeveloperAPI
def batch(
list_of_structs: List[Any],
*,
individual_items_already_have_batch_dim: Union[bool, str] = False,
):
"""Converts input from a list of (nested) structs to a (nested) struct of batches.
Input: List of structs (each of these structs representing a single batch item).
[
{"a": 1, "b": (4, 7.0)}, <- batch item 1
{"a": 2, "b": (5, 8.0)}, <- batch item 2
{"a": 3, "b": (6, 9.0)}, <- batch item 3
]
Output: Struct of different batches (each batch has size=3 b/c there were 3 items
in the original list):
{
"a": np.array([1, 2, 3]),
"b": (np.array([4, 5, 6]), np.array([7.0, 8.0, 9.0]))
}
Args:
list_of_structs: The list of (possibly nested) structs. Each item
in this list represents a single batch item.
individual_items_already_have_batch_dim: True, if the individual items in
`list_of_structs` already have a batch dim. In this case, we will
concatenate (instead of stack) at the end. In the example above, this would
look like this: Input: [{"a": [1], "b": ([4], [7.0])}, ...] -> Output: same
as in above example.
If the special value "auto" is used,
Returns:
The struct of component batches. Each leaf item in this struct represents the
batch for a single component (in case struct is tuple/dict). If the input is a
simple list of primitive items, e.g. a list of floats, a np.array of floats
will be returned.
"""
if not list_of_structs:
raise ValueError("Input `list_of_structs` does not contain any items.")
first = list_of_structs[0]
# Nested structures (dict/tuple) require tree traversal; leaves do not.
is_nested = isinstance(first, (dict, tuple))
# TODO (sven): Maybe replace this by a list-override (usage of which indicated
# this method that concatenate should be used (not stack)).
if individual_items_already_have_batch_dim == "auto":
if isinstance(first, BatchedNdArray):
individual_items_already_have_batch_dim = True
elif is_nested:
flat = tree.flatten(first)
individual_items_already_have_batch_dim = isinstance(
flat[0], BatchedNdArray
)
else:
individual_items_already_have_batch_dim = False
if individual_items_already_have_batch_dim:
if is_nested:
ret = tree.map_structure(
lambda *s: np.concatenate(s, axis=0), *list_of_structs
)
else:
# Fast path: simple numpy arrays or scalars — no tree traversal needed.
ret = np.concatenate(list_of_structs, axis=0)
else:
n = len(list_of_structs)
def fast_stack(*s):
# NOTE (Artur): This is a faster version of np.stack as per my benchmarks.
s0 = s[0]
if not isinstance(s0, np.ndarray):
return np.array(s)
out = np.empty((n, *s0.shape), dtype=s0.dtype)
for i in range(n):
out[i] = s[i]
return out
if is_nested:
ret = tree.map_structure(fast_stack, *list_of_structs)
else:
# Fast path: simple numpy arrays or scalars — no tree traversal needed.
ret = fast_stack(*list_of_structs)
return ret
@DeveloperAPI
def unbatch(batches_struct):
"""Converts input from (nested) struct of batches to batch of structs.
Input: Struct of different batches (each batch has size=3):
{
"a": np.array([1, 2, 3]),
"b": (np.array([4, 5, 6]), np.array([7.0, 8.0, 9.0]))
}
Output: Batch (list) of structs (each of these structs representing a
single action):
[
{"a": 1, "b": (4, 7.0)}, <- action 1
{"a": 2, "b": (5, 8.0)}, <- action 2
{"a": 3, "b": (6, 9.0)}, <- action 3
]
Args:
batches_struct: The struct of component batches. Each leaf item
in this struct represents the batch for a single component
(in case struct is tuple/dict).
Alternatively, `batches_struct` may also simply be a batch of
primitives (non tuple/dict).
Returns:
The list of individual structs. Each item in the returned list represents a
single (maybe complex) batch item.
"""
flat_batches = tree.flatten(batches_struct)
out = []
for batch_pos in range(len(flat_batches[0])):
out.append(
tree.unflatten_as(
batches_struct,
[flat_batches[i][batch_pos] for i in range(len(flat_batches))],
)
)
return out
@DeveloperAPI
def clip_action(action, action_space):
"""Clips all components in `action` according to the given Space.
Only applies to Box components within the action space.
Args:
action: The action to be clipped. This could be any complex
action, e.g. a dict or tuple.
action_space: The action space struct,
e.g. `{"a": Distrete(2)}` for a space: Dict({"a": Discrete(2)}).
Returns:
Any: The input action, but clipped by value according to the space's
bounds.
"""
def map_(a, s):
if isinstance(s, gym.spaces.Box):
a = np.clip(a, s.low, s.high)
return a
return tree.map_structure(map_, action, action_space)
@DeveloperAPI
def unsquash_action(action, action_space_struct):
"""Unsquashes all components in `action` according to the given Space.
Inverse of `normalize_action()`. Useful for mapping policy action
outputs (normalized between -1.0 and 1.0) to an env's action space.
Unsquashing results in cont. action component values between the
given Space's bounds (`low` and `high`). This only applies to Box
components within the action space, whose dtype is float32 or float64.
Args:
action: The action to be unsquashed. This could be any complex
action, e.g. a dict or tuple.
action_space_struct: The action space struct,
e.g. `{"a": Box()}` for a space: Dict({"a": Box()}).
Returns:
Any: The input action, but unsquashed, according to the space's
bounds. An unsquashed action is ready to be sent to the
environment (`BaseEnv.send_actions([unsquashed actions])`).
"""
def map_(a, s):
if (
isinstance(s, gym.spaces.Box)
and np.all(s.bounded_below)
and np.all(s.bounded_above)
):
if s.dtype == np.float32 or s.dtype == np.float64:
# Assuming values are roughly between -1.0 and 1.0 ->
# unsquash them to the given bounds.
a = s.low + (a + 1.0) * (s.high - s.low) / 2.0
# Clip to given bounds, just in case the squashed values were
# outside [-1.0, 1.0].
a = np.clip(a, s.low, s.high)
elif np.issubdtype(s.dtype, np.integer):
# For Categorical and MultiCategorical actions, shift the selection
# into the proper range.
a = s.low + a
return a
return tree.map_structure(map_, action, action_space_struct)
@DeveloperAPI
def normalize_action(action, action_space_struct):
"""Normalizes all (Box) components in `action` to be in [-1.0, 1.0].
Inverse of `unsquash_action()`. Useful for mapping an env's action
(arbitrary bounded values) to a [-1.0, 1.0] interval.
This only applies to Box components within the action space, whose
dtype is float32 or float64.
Args:
action: The action to be normalized. This could be any complex
action, e.g. a dict or tuple.
action_space_struct: The action space struct,
e.g. `{"a": Box()}` for a space: Dict({"a": Box()}).
Returns:
Any: The input action, but normalized, according to the space's
bounds.
"""
def map_(a, s):
if isinstance(s, gym.spaces.Box) and (
s.dtype == np.float32 or s.dtype == np.float64
):
# Normalize values to be exactly between -1.0 and 1.0.
a = ((a - s.low) * 2.0) / (s.high - s.low) - 1.0
return a
return tree.map_structure(map_, action, action_space_struct)
@DeveloperAPI
def convert_element_to_space_type(element: Any, sampled_element: Any) -> Any:
"""Convert all the components of the element to match the space dtypes.
Args:
element: The element to be converted.
sampled_element: An element sampled from a space to be matched
to.
Returns:
The input element, but with all its components converted to match
the space dtypes.
"""
def map_(elem, s):
if isinstance(s, np.ndarray):
if not isinstance(elem, np.ndarray):
assert isinstance(
elem, (float, int)
), f"ERROR: `elem` ({elem}) must be np.array, float or int!"
if s.shape == ():
elem = np.array(elem, dtype=s.dtype)
else:
raise ValueError(
"Element should be of type np.ndarray but is instead of \
type {}".format(
type(elem)
)
)
elif s.dtype != elem.dtype:
elem = elem.astype(s.dtype)
# Gymnasium now uses np.int_64 as the dtype of a Discrete action space
elif isinstance(s, int) or isinstance(s, np.intp):
if isinstance(elem, float) and elem.is_integer():
elem = int(elem)
# Note: This does not check if the float element is actually an integer
if isinstance(elem, np.floating):
elem = np.int64(elem)
return elem
return tree.map_structure(map_, element, sampled_element, check_types=False)