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Gymnasium/gym/spaces/multi_discrete.py

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2.9 KiB
Python

from __future__ import annotations
from collections.abc import Sequence
import numpy as np
from gym import logger
from .discrete import Discrete
from .space import Space
class MultiDiscrete(Space[np.ndarray]):
"""
The multi-discrete action space consists of a series of discrete action spaces with different number of actions in each. It is useful to represent game controllers or keyboards where each key can be represented as a discrete action space. It is parametrized by passing an array of positive integers specifying number of actions for each discrete action space.
Note:
Some environment wrappers assume a value of 0 always represents the NOOP action.
e.g. Nintendo Game Controller - Can be conceptualized as 3 discrete action spaces:
1. Arrow Keys: Discrete 5 - NOOP[0], UP[1], RIGHT[2], DOWN[3], LEFT[4] - params: min: 0, max: 4
2. Button A: Discrete 2 - NOOP[0], Pressed[1] - params: min: 0, max: 1
3. Button B: Discrete 2 - NOOP[0], Pressed[1] - params: min: 0, max: 1
It can be initialized as ``MultiDiscrete([ 5, 2, 2 ])``
"""
def __init__(self, nvec: list[int], dtype=np.int64, seed=None):
"""
nvec: vector of counts of each categorical variable
"""
self.nvec = np.array(nvec, dtype=dtype, copy=True)
assert (self.nvec > 0).all(), "nvec (counts) have to be positive"
super().__init__(self.nvec.shape, dtype, seed)
@property
def shape(self) -> tuple[int, ...]:
"""Has stricter type than gym.Space - never None."""
return self._shape # type: ignore
def sample(self) -> np.ndarray:
return (self.np_random.random(self.nvec.shape) * self.nvec).astype(self.dtype)
def contains(self, x) -> bool:
if isinstance(x, Sequence):
x = np.array(x) # Promote list to array for contains check
# if nvec is uint32 and space dtype is uint32, then 0 <= x < self.nvec guarantees that x
# is within correct bounds for space dtype (even though x does not have to be unsigned)
return bool(x.shape == self.shape and (0 <= x).all() and (x < self.nvec).all())
def to_jsonable(self, sample_n):
return [sample.tolist() for sample in sample_n]
def from_jsonable(self, sample_n):
return np.array(sample_n)
def __repr__(self):
return f"MultiDiscrete({self.nvec})"
def __getitem__(self, index):
nvec = self.nvec[index]
if nvec.ndim == 0:
subspace = Discrete(nvec)
else:
subspace = MultiDiscrete(nvec, self.dtype)
subspace.np_random.bit_generator.state = self.np_random.bit_generator.state
return subspace
def __len__(self):
if self.nvec.ndim >= 2:
logger.warn("Get length of a multi-dimensional MultiDiscrete space.")
return len(self.nvec)
def __eq__(self, other):
return isinstance(other, MultiDiscrete) and np.all(self.nvec == other.nvec)