vecrl
This namespace provides various vectorized reinforcement learning utilities.
Policy
¶
A Policy for deciding the actions for a reinforcement learning environment.
This can be seen as a stateful wrapper around a PyTorch module.
Let us assume that we have the following PyTorch module:
which has 48 parameters (when all the parameters are flattened).
Let us randomly generate a parameter vector for our module net
:
We can now prepare a policy:
If we generate a random observation:
We can receive our action as follows:
If the PyTorch module that we wish to wrap is a recurrent network (i.e. a network which expects an optional second argument for the hidden state, and returns a second value which represents the updated hidden state), then, the hidden state is automatically managed by the Policy instance.
Let us assume that we have a recurrent network named recnet
.
In this case, because the hidden state of the network is internally managed, the usage is still the same with our previous nonrecurrent
Examples:
When using a recurrent module on multiple episodes, it is important to reset the hidden state of the network. This is achieved by the reset method:
policy.reset()
action1 = policy(observation1)
# action2 will be computed with the hidden state generated by the
# previous forwardpass.
action2 = policy(observation2)
policy.reset()
# action3 will be computed according to the renewed hidden state.
action3 = policy(observation3)
Both for nonrecurrent and recurrent networks, it is possible to perform vectorized operations. For now, let us return to our first nonrecurrent example:
Instead of generating only one parameter vector, we now generate a batch of parameter vectors. Let us say that our batch size is 10:
Like we did in the nonbatched examples, we can do:
Because we are now in the batched mode, policy
now expects a batch
of observations and will return a batch of actions:
When doing vectorized reinforcement learning with a recurrent module,
it can be the case that only some of the environments are finished,
and therefore it is necessary to reset the hidden states associated
with those environments only. The reset(...)
method of Policy
has a second argument to specify which of the recurrent network
instances are to be reset. For example, if the episodes of the
environments with indices 2 and 5 are about to restart (and therefore
we wish to reset the states of the networks with indices 2 and 5),
then, we can do:
Source code in evotorch/neuroevolution/net/vecrl.py
class Policy:
"""
A Policy for deciding the actions for a reinforcement learning environment.
This can be seen as a stateful wrapper around a PyTorch module.
Let us assume that we have the following PyTorch module:
```python
from torch import nn
net = nn.Linear(5, 8)
```
which has 48 parameters (when all the parameters are flattened).
Let us randomly generate a parameter vector for our module `net`:
```python
parameters = torch.randn(48)
```
We can now prepare a policy:
```python
policy = Policy(net)
policy.set_parameters(parameters)
```
If we generate a random observation:
```python
observation = torch.randn(5)
```
We can receive our action as follows:
```python
action = policy(observation)
```
If the PyTorch module that we wish to wrap is a recurrent network (i.e.
a network which expects an optional second argument for the hidden state,
and returns a second value which represents the updated hidden state),
then, the hidden state is automatically managed by the Policy instance.
Let us assume that we have a recurrent network named `recnet`.
```python
policy = Policy(recnet)
policy.set_parameters(parameters_of_recnet)
```
In this case, because the hidden state of the network is internally
managed, the usage is still the same with our previous nonrecurrent
example:
```python
action = policy(observation)
```
When using a recurrent module on multiple episodes, it is important
to reset the hidden state of the network. This is achieved by the
reset method:
```python
policy.reset()
action1 = policy(observation1)
# action2 will be computed with the hidden state generated by the
# previous forwardpass.
action2 = policy(observation2)
policy.reset()
# action3 will be computed according to the renewed hidden state.
action3 = policy(observation3)
```
Both for nonrecurrent and recurrent networks, it is possible to
perform vectorized operations. For now, let us return to our
first nonrecurrent example:
```python
net = nn.Linear(5, 8)
```
Instead of generating only one parameter vector, we now generate
a batch of parameter vectors. Let us say that our batch size is 10:
```python
batch_of_parameters = torch.randn(10, 48)
```
Like we did in the nonbatched examples, we can do:
```python
policy = Policy(net)
policy.set_parameters(batch_of_parameters)
```
Because we are now in the batched mode, `policy` now expects a batch
of observations and will return a batch of actions:
```python
batch_of_observations = torch.randn(10, 5)
batch_of_actions = policy(batch_of_observations)
```
When doing vectorized reinforcement learning with a recurrent module,
it can be the case that only some of the environments are finished,
and therefore it is necessary to reset the hidden states associated
with those environments only. The `reset(...)` method of Policy
has a second argument to specify which of the recurrent network
instances are to be reset. For example, if the episodes of the
environments with indices 2 and 5 are about to restart (and therefore
we wish to reset the states of the networks with indices 2 and 5),
then, we can do:
```python
policy.reset(torch.tensor([2, 5]))
```
"""
def __init__(self, net: Union[str, Callable, nn.Module], **kwargs):
"""
`__init__(...)`: Initialize the Policy.
Args:
net: The network to be wrapped by the Policy object.
This can be a string, a Callable (e.g. a `torch.nn.Module`
subclass), or a `torch.nn.Module` instance.
When this argument is a string, the network will be
created with the help of the function
`evotorch.neuroevolution.net.str_to_net(...)` and then
wrapped. Please see the `str_to_net(...)` function's
documentation for details regarding how a network structure
can be expressed via strings.
kwargs: Expected in the form of additional keyword arguments,
these keyword arguments will be passed to the provided
Callable object (if the argument `net` is a Callable)
or to `str_to_net(...)` (if the argument `net` is a string)
at the moment of generating the network.
If the argument `net` is a `torch.nn.Module` instance,
having any additional keyword arguments will trigger an
error, because the network is already instantiated and
therefore, it is not possible to pass these keyword arguments.
"""
from ..net import str_to_net
from ..net.functional import ModuleExpectingFlatParameters, make_functional_module
if isinstance(net, str):
self.__module = str_to_net(net, **kwargs)
elif isinstance(net, nn.Module):
if len(kwargs) > 0:
raise ValueError(
f"When the network is given as an `nn.Module` instance, extra network arguments cannot be used"
f" (because the network is already instantiated)."
f" However, these extra keyword arguments were received: {kwargs}."
)
self.__module = net
elif isinstance(net, Callable):
self.__module = net(**kwargs)
else:
raise TypeError(
f"The class `Policy` expected a string or an `nn.Module` instance, or a Callable, but received {net}"
f" (whose type is {type(net)})."
)
self.__fmodule: ModuleExpectingFlatParameters = make_functional_module(self.__module)
self.__state: Any = None
self.__parameters: Optional[torch.Tensor] = None
def set_parameters(self, parameters: torch.Tensor, indices: Optional[MaskOrIndices] = None, *, reset: bool = True):
"""
Set the parameters of the policy.
Args:
parameters: A 1dimensional or a 2dimensional tensor containing
the flattened parameters to be used with the neural network.
If the given parameters are twodimensional, then, given that
the leftmost size of the parameter tensor is `n`, the
observations will be expected in a batch with leftmost size
`n`, and the returned actions will also be in a batch,
again with the leftmost size `n`.
indices: For when the parameters were previously given via a
2dimensional tensor, provide this argument if you would like
to change only some rows of the previously given parameters.
For example, if `indices` is given as `torch.tensor([2, 4])`
and the argument `parameters` is given as a 2dimensional
tensor with leftmost size 2, then the rows with indices
2 and 4 will be replaced by these new parameters provided
via the argument `parameters`.
reset: If given as True, the hidden states of the networks whose
parameters just changed will be reset. If `indices` was not
provided at all, then this means that the parameters of all
networks are modified, in which case, all the hidden states
will be reset.
If given as False, no such resetting will be done.
"""
if self.__parameters is None:
if indices is not None:
raise ValueError(
"The argument `indices` can be used only if network parameters were previously specified."
" However, it seems that the method `set_parameters(...)` was not called before."
)
self.__parameters = parameters
else:
if indices is None:
self.__parameters = parameters
else:
self.__parameters[indices] = parameters
if reset:
self.reset(indices)
def __call__(self, x: torch.Tensor) > torch.Tensor:
"""
Pass the given observations through the network.
Args:
x: The observations, as a PyTorch tensor.
If the parameters were given (via the method
`set_parameters(...)`) as a 1dimensional tensor, then this
argument is expected to store a single observation.
If the parameters were given as a 2dimensional tensor,
then, this argument is expected to store a batch of
observations, and the leftmost size of this observation
tensor must match with the leftmost size of the parameter
tensor.
Returns:
The output tensor, which represents the action to take.
"""
if self.__parameters is None:
raise ValueError("Please use the method `set_parameters(...)` before calling the policy.")
if self.__state is None:
further_args = (x,)
else:
further_args = (x, self.__state)
parameters = self.__parameters
ndim = parameters.ndim
if ndim == 1:
result = self.__fmodule(parameters, *further_args)
elif ndim == 2:
vmapped = vmap(self.__fmodule)
result = vmapped(parameters, *further_args)
else:
raise ValueError(
f"Expected the parameters as a 1 or 2 dimensional tensor."
f" However, the received parameters tensor has {ndim} dimensions."
)
if isinstance(result, torch.Tensor):
return result
elif isinstance(result, tuple):
result, state = result
self.__state = state
return result
else:
raise TypeError(f"The torch module used by the Policy returned an unexpected object: {result}")
def reset(self, indices: Optional[MaskOrIndices] = None, *, copy: bool = True):
"""
Reset the hidden states, if the contained module is a recurrent network.
Args:
indices: Optionally a sequence of integers or a sequence of
booleans, specifying which networks' states will be
reset. If left as None, then the states of all the networks
will be reset.
copy: When `indices` is given as something other than None,
if `copy` is given as True, then the resetting will NOT
be done inplace. Instead, a new copy of the hidden state
will first be created, and then the specified regions
of this new copy will be cleared, and then finally this
modified copy will be declared as the new hidden state.
It is a common practice for recurrent neural network
implementations to return the same tensor both as its
output and as (part of) its hidden state. With `copy=False`,
the resetting would be done inplace, and the action
tensor could be involuntarily reset as well.
This inplace modification could cause silent bugs
if the unintended modification on the action tensor
happens BEFORE the action is sent to the reinforcement
learning environment.
To prevent such situations, the default value for the argument
`copy` is True.
"""
if indices is None:
self.__state = None
else:
if self.__state is not None:
with torch.no_grad():
if copy:
self.__state = deepcopy(self.__state)
reset_tensors(self.__state, indices)
@property
def parameters(self) > torch.Tensor:
"""
The currently used parameters.
"""
return self.__parameters
@property
def h(self) > Optional[torch.Tensor]:
"""
The hidden state of the contained recurrent network, if any.
If the contained recurrent network did not generate a hidden state
yet, or if the contained network is not recurrent, then the result
will be None.
"""
return self.__state
@property
def parameter_length(self) > int:
"""
Length of the parameter tensor.
"""
return self.__fmodule.parameter_length
@property
def wrapped_module(self) > nn.Module:
"""
The wrapped `torch.nn.Module` instance.
"""
return self.__module
def to_torch_module(self, parameter_vector: torch.Tensor) > nn.Module:
"""
Get a copy of the contained network, parameterized as specified.
Args:
parameter_vector: The parameters to be used by the new network.
Returns:
Copy of the contained network, as a `torch.nn.Module` instance.
"""
with torch.no_grad():
net = deepcopy(self.__module).to(parameter_vector.device)
nnu.vector_to_parameters(parameter_vector, net.parameters())
return net
h: Optional[torch.Tensor]
property
readonly
¶
The hidden state of the contained recurrent network, if any.
If the contained recurrent network did not generate a hidden state yet, or if the contained network is not recurrent, then the result will be None.
parameter_length: int
property
readonly
¶
Length of the parameter tensor.
parameters: Tensor
property
readonly
¶
The currently used parameters.
wrapped_module: Module
property
readonly
¶
The wrapped torch.nn.Module
instance.
__call__(self, x)
special
¶
Pass the given observations through the network.
Parameters:
Name  Type  Description  Default 

x 
Tensor 
The observations, as a PyTorch tensor.
If the parameters were given (via the method

required 
Returns:
Type  Description 

Tensor 
The output tensor, which represents the action to take. 
Source code in evotorch/neuroevolution/net/vecrl.py
def __call__(self, x: torch.Tensor) > torch.Tensor:
"""
Pass the given observations through the network.
Args:
x: The observations, as a PyTorch tensor.
If the parameters were given (via the method
`set_parameters(...)`) as a 1dimensional tensor, then this
argument is expected to store a single observation.
If the parameters were given as a 2dimensional tensor,
then, this argument is expected to store a batch of
observations, and the leftmost size of this observation
tensor must match with the leftmost size of the parameter
tensor.
Returns:
The output tensor, which represents the action to take.
"""
if self.__parameters is None:
raise ValueError("Please use the method `set_parameters(...)` before calling the policy.")
if self.__state is None:
further_args = (x,)
else:
further_args = (x, self.__state)
parameters = self.__parameters
ndim = parameters.ndim
if ndim == 1:
result = self.__fmodule(parameters, *further_args)
elif ndim == 2:
vmapped = vmap(self.__fmodule)
result = vmapped(parameters, *further_args)
else:
raise ValueError(
f"Expected the parameters as a 1 or 2 dimensional tensor."
f" However, the received parameters tensor has {ndim} dimensions."
)
if isinstance(result, torch.Tensor):
return result
elif isinstance(result, tuple):
result, state = result
self.__state = state
return result
else:
raise TypeError(f"The torch module used by the Policy returned an unexpected object: {result}")
__init__(self, net, **kwargs)
special
¶
__init__(...)
: Initialize the Policy.
Parameters:
Name  Type  Description  Default 

net 
Union[str, Callable, torch.nn.modules.module.Module] 
The network to be wrapped by the Policy object.
This can be a string, a Callable (e.g. a 
required 
kwargs 
Expected in the form of additional keyword arguments,
these keyword arguments will be passed to the provided
Callable object (if the argument 
{} 
Source code in evotorch/neuroevolution/net/vecrl.py
def __init__(self, net: Union[str, Callable, nn.Module], **kwargs):
"""
`__init__(...)`: Initialize the Policy.
Args:
net: The network to be wrapped by the Policy object.
This can be a string, a Callable (e.g. a `torch.nn.Module`
subclass), or a `torch.nn.Module` instance.
When this argument is a string, the network will be
created with the help of the function
`evotorch.neuroevolution.net.str_to_net(...)` and then
wrapped. Please see the `str_to_net(...)` function's
documentation for details regarding how a network structure
can be expressed via strings.
kwargs: Expected in the form of additional keyword arguments,
these keyword arguments will be passed to the provided
Callable object (if the argument `net` is a Callable)
or to `str_to_net(...)` (if the argument `net` is a string)
at the moment of generating the network.
If the argument `net` is a `torch.nn.Module` instance,
having any additional keyword arguments will trigger an
error, because the network is already instantiated and
therefore, it is not possible to pass these keyword arguments.
"""
from ..net import str_to_net
from ..net.functional import ModuleExpectingFlatParameters, make_functional_module
if isinstance(net, str):
self.__module = str_to_net(net, **kwargs)
elif isinstance(net, nn.Module):
if len(kwargs) > 0:
raise ValueError(
f"When the network is given as an `nn.Module` instance, extra network arguments cannot be used"
f" (because the network is already instantiated)."
f" However, these extra keyword arguments were received: {kwargs}."
)
self.__module = net
elif isinstance(net, Callable):
self.__module = net(**kwargs)
else:
raise TypeError(
f"The class `Policy` expected a string or an `nn.Module` instance, or a Callable, but received {net}"
f" (whose type is {type(net)})."
)
self.__fmodule: ModuleExpectingFlatParameters = make_functional_module(self.__module)
self.__state: Any = None
self.__parameters: Optional[torch.Tensor] = None
reset(self, indices=None, *, copy=True)
¶
Reset the hidden states, if the contained module is a recurrent network.
Parameters:
Name  Type  Description  Default 

indices 
Union[int, Iterable] 
Optionally a sequence of integers or a sequence of booleans, specifying which networks' states will be reset. If left as None, then the states of all the networks will be reset. 
None 
copy 
bool 
When 
True 
Source code in evotorch/neuroevolution/net/vecrl.py
def reset(self, indices: Optional[MaskOrIndices] = None, *, copy: bool = True):
"""
Reset the hidden states, if the contained module is a recurrent network.
Args:
indices: Optionally a sequence of integers or a sequence of
booleans, specifying which networks' states will be
reset. If left as None, then the states of all the networks
will be reset.
copy: When `indices` is given as something other than None,
if `copy` is given as True, then the resetting will NOT
be done inplace. Instead, a new copy of the hidden state
will first be created, and then the specified regions
of this new copy will be cleared, and then finally this
modified copy will be declared as the new hidden state.
It is a common practice for recurrent neural network
implementations to return the same tensor both as its
output and as (part of) its hidden state. With `copy=False`,
the resetting would be done inplace, and the action
tensor could be involuntarily reset as well.
This inplace modification could cause silent bugs
if the unintended modification on the action tensor
happens BEFORE the action is sent to the reinforcement
learning environment.
To prevent such situations, the default value for the argument
`copy` is True.
"""
if indices is None:
self.__state = None
else:
if self.__state is not None:
with torch.no_grad():
if copy:
self.__state = deepcopy(self.__state)
reset_tensors(self.__state, indices)
set_parameters(self, parameters, indices=None, *, reset=True)
¶
Set the parameters of the policy.
Parameters:
Name  Type  Description  Default 

parameters 
Tensor 
A 1dimensional or a 2dimensional tensor containing
the flattened parameters to be used with the neural network.
If the given parameters are twodimensional, then, given that
the leftmost size of the parameter tensor is 
required 
indices 
Union[int, Iterable] 
For when the parameters were previously given via a
2dimensional tensor, provide this argument if you would like
to change only some rows of the previously given parameters.
For example, if 
None 
reset 
bool 
If given as True, the hidden states of the networks whose
parameters just changed will be reset. If 
True 
Source code in evotorch/neuroevolution/net/vecrl.py
def set_parameters(self, parameters: torch.Tensor, indices: Optional[MaskOrIndices] = None, *, reset: bool = True):
"""
Set the parameters of the policy.
Args:
parameters: A 1dimensional or a 2dimensional tensor containing
the flattened parameters to be used with the neural network.
If the given parameters are twodimensional, then, given that
the leftmost size of the parameter tensor is `n`, the
observations will be expected in a batch with leftmost size
`n`, and the returned actions will also be in a batch,
again with the leftmost size `n`.
indices: For when the parameters were previously given via a
2dimensional tensor, provide this argument if you would like
to change only some rows of the previously given parameters.
For example, if `indices` is given as `torch.tensor([2, 4])`
and the argument `parameters` is given as a 2dimensional
tensor with leftmost size 2, then the rows with indices
2 and 4 will be replaced by these new parameters provided
via the argument `parameters`.
reset: If given as True, the hidden states of the networks whose
parameters just changed will be reset. If `indices` was not
provided at all, then this means that the parameters of all
networks are modified, in which case, all the hidden states
will be reset.
If given as False, no such resetting will be done.
"""
if self.__parameters is None:
if indices is not None:
raise ValueError(
"The argument `indices` can be used only if network parameters were previously specified."
" However, it seems that the method `set_parameters(...)` was not called before."
)
self.__parameters = parameters
else:
if indices is None:
self.__parameters = parameters
else:
self.__parameters[indices] = parameters
if reset:
self.reset(indices)
to_torch_module(self, parameter_vector)
¶
Get a copy of the contained network, parameterized as specified.
Parameters:
Name  Type  Description  Default 

parameter_vector 
Tensor 
The parameters to be used by the new network. 
required 
Returns:
Type  Description 

Module 
Copy of the contained network, as a 
Source code in evotorch/neuroevolution/net/vecrl.py
def to_torch_module(self, parameter_vector: torch.Tensor) > nn.Module:
"""
Get a copy of the contained network, parameterized as specified.
Args:
parameter_vector: The parameters to be used by the new network.
Returns:
Copy of the contained network, as a `torch.nn.Module` instance.
"""
with torch.no_grad():
net = deepcopy(self.__module).to(parameter_vector.device)
nnu.vector_to_parameters(parameter_vector, net.parameters())
return net
TorchWrapper (Wrapper)
¶
A gym wrapper which ensures that the actions, observations, rewards, and the 'done' values are expressed as PyTorch tensors.
Source code in evotorch/neuroevolution/net/vecrl.py
class TorchWrapper(gym.Wrapper):
"""
A gym wrapper which ensures that the actions, observations, rewards, and
the 'done' values are expressed as PyTorch tensors.
"""
def __init__(
self,
env: Union[gym.Env],
*,
force_classic_api: bool = False,
discrete_to_continuous_act: bool = False,
clip_actions: bool = False,
**kwargs,
):
"""
`__init__(...)`: Initialize the TorchWrapper.
Args:
env: The gym environment to be wrapped.
force_classic_api: Set this as True if you would like to enable
the classic API. In the classic API, the `reset(...)` method
returns only the observation and the `step(...)` method
returns 4 elements (not 5).
discrete_to_continuous_act: When this is set as True and the
wrapped environment has a Discrete action space, this wrapper
will transform the action space to Box. A Discreteaction
environment with `n` actions will be converted to a Boxaction
environment where the action length is `n`.
The index of the largest value within the action vector will
be applied to the underlying environment.
clip_actions: Set this as True if you would like to clip the given
actions so that they conform to the declared boundaries of the
action space.
kwargs: Expected in the form of additional keyword arguments.
These additional keyword arguments are passed to the
superclass.
"""
super().__init__(env, **kwargs)
# Declare the variable that will store the array type of the underlying environment.
self.__array_type: Optional[str] = None
if hasattr(env, "single_observation_space"):
# If the underlying environment has the attribute "single_observation_space",
# then this is a vectorized environment.
self.__vectorized = True
# Get the observation and action spaces.
obs_space = env.single_observation_space
act_space = env.single_action_space
else:
# If the underlying environment has the attribute "single_observation_space",
# then this is a nonvectorized environment.
self.__vectorized = False
# Get the observation and action spaces.
obs_space = env.observation_space
act_space = env.action_space
# Ensure that the observation and action spaces are supported.
_must_be_supported_space(obs_space)
_must_be_supported_space(act_space)
# Store the choice of the user regarding "force_classic_api".
self.__force_classic_api = bool(force_classic_api)
if isinstance(act_space, Discrete) and discrete_to_continuous_act:
# The underlying action space is Discrete and `discrete_to_continuous_act` is given as True.
# Therefore, we convert the action space to continuous (to Box).
# Take the shape and the dtype of the discrete action space.
single_action_shape = (act_space.n,)
single_action_dtype = torch.from_numpy(np.array([], dtype=act_space.dtype)).dtype
# We store the integer dtype of the environment.
self.__discrete_dtype = single_action_dtype
if self.__vectorized:
# If the environment is vectorized, we declare the new `action_space` and the `single_action_space`
# for the enviornment.
action_shape = (env.num_envs,) + single_action_shape
self.single_action_space = Box(float("inf"), float("inf"), shape=single_action_shape, dtype=np.float32)
self.action_space = Box(float("inf"), float("inf"), shape=action_shape, dtype=np.float32)
else:
# If the environment is not vectorized, we declare the new `action_space` for the environment.
self.action_space = Box(float("inf"), float("inf"), shape=single_action_shape, dtype=np.float32)
else:
# This is the case where we do not transform the action space.
# The discrete dtype will not be used, so, we set it as None.
self.__discrete_dtype = None
if isinstance(act_space, Box) and clip_actions:
# If the action space is Box and the wrapper is configured to clip the actions, then we store the lower
# and the upper bounds for the actions.
self.__act_lb = torch.from_numpy(act_space.low)
self.__act_ub = torch.from_numpy(act_space.high)
else:
# If there will not be any action clipping, then we store the lower and the upper bounds as None.
self.__act_lb = None
self.__act_ub = None
@property
def array_type(self) > Optional[str]:
"""
Get the array type of the wrapped environment.
This can be "jax", "torch", or "numpy".
"""
return self.__array_type
def __infer_array_type(self, observation):
if self.__array_type is None:
# If the array type is not determined yet, set it as the array type of the received observation.
# If the observation has an unrecognized type, set the array type as "numpy".
self.__array_type = array_type(observation, "numpy")
def reset(self, *args, **kwargs):
"""Reset the environment"""
# Call the reset method of the wrapped environment.
reset_result = self.env.reset(*args, **kwargs)
if isinstance(reset_result, tuple):
# If we received a tuple of two elements, then we assume that this is the new gym API.
# We note that we received an info dictionary.
got_info = True
# We keep the received observation and info.
observation, info = reset_result
else:
# If we did not receive a tuple, then we assume that this is the old gym API.
# We note that we did not receive an info dictionary.
got_info = False
# We keep the received observation.
observation = reset_result
# We did not receive an info dictionary, so, we set it as an empty dictionary.
info = {}
# We understand the array type of the underlying environment from the first observation.
self.__infer_array_type(observation)
# Convert the observation to a PyTorch tensor.
observation = convert_to_torch(observation)
if self.__force_classic_api:
# If the option `force_classic_api` was set as True, then we only return the observation.
return observation
else:
# Here we handle the case where `force_classic_api` was set as False.
if got_info:
# If we got an additional info dictionary, we return it next to the observation.
return observation, info
else:
# If we did not get any info dictionary, we return only the observation.
return observation
def step(self, action, *args, **kwargs):
"""Take a step in the environment"""
if self.__array_type is None:
# If the array type is not known yet, then probably `reset()` has not been called yet.
# We raise an error.
raise ValueError(
"Could not understand what type of array this environment works with."
" Perhaps the `reset()` method has not been called yet?"
)
if self.__discrete_dtype is not None:
# If the wrapped environment is discreteactioned, then we take the integer counterpart of the action.
action = torch.argmax(action, dim=1).to(dtype=self.__discrete_dtype)
if self.__act_lb is not None:
# The internal variable `__act_lb` having a value other than None means that the initialization argument
# `clip_actions` was given as True.
# Therefore, we clip the actions.
self.__act_lb = self.__act_lb.to(action.device)
self.__act_ub = self.__act_ub.to(action.device)
action = torch.max(action, self.__act_lb)
action = torch.min(action, self.__act_ub)
# Convert the action tensor to the expected array type of the underlying environment.
action = convert_from_torch(action, self.__array_type)
# Perform the step and get the result.
result = self.env.step(action, *args, **kwargs)
if not isinstance(result, tuple):
# If the `step(...)` method returned anything other than tuple, we raise an error.
raise TypeError(f"Expected a tuple as the result of the `step()` method, but received a {type(result)}")
if len(result) == 5:
# If the result is a tuple of 5 elements, then we note that we are using the new API.
using_new_api = True
# Take the observation, reward, two boolean variables done and done2 indicating that the episode(s)
# has/have ended, and additional info.
# `done` indicates whether or not the episode(s) reached terminal state(s).
# `done2` indicates whether or not the episode(s) got truncated because of the timestep limit.
observation, reward, done, done2, info = result
elif len(result) == 4:
# If the result is a tuple of 5 elements, then we note that we are not using the new API.
using_new_api = False
# Take the observation, reward, the done boolean flag, and additional info.
observation, reward, done, info = result
done2 = None
else:
raise ValueError(f"Unexpected number of elements were returned from step(): {len(result)}")
# Convert the observation, reward, and done variables to PyTorch tensors.
observation = convert_to_torch(observation)
reward = convert_to_torch(reward)
done = convert_to_torch_bool(done)
if done2 is not None:
done2 = convert_to_torch_bool(done2)
if self.__force_classic_api:
# This is the case where the initialization argument `force_classic_api` was set as True.
if done2 is not None:
# We combine the terminal state and truncation signals into a single boolean tensor indicating
# whether or not the episode(s) ended.
done = done  done2
# Return 4 elements, compatible with the classic gym API.
return observation, reward, done, info
else:
# This is the case where the initialization argument `force_classic_api` was set as False.
if using_new_api:
# If we are using the new API, then we return the 5element result.
return observation, reward, done, done2, info
else:
# If we are using the new API, then we return the 4element result.
return observation, reward, done, info
array_type: Optional[str]
property
readonly
¶
Get the array type of the wrapped environment. This can be "jax", "torch", or "numpy".
__init__(self, env, *, force_classic_api=False, discrete_to_continuous_act=False, clip_actions=False, **kwargs)
special
¶
__init__(...)
: Initialize the TorchWrapper.
Parameters:
Name  Type  Description  Default 

env 
Env 
The gym environment to be wrapped. 
required 
force_classic_api 
bool 
Set this as True if you would like to enable
the classic API. In the classic API, the 
False 
discrete_to_continuous_act 
bool 
When this is set as True and the
wrapped environment has a Discrete action space, this wrapper
will transform the action space to Box. A Discreteaction
environment with 
False 
clip_actions 
bool 
Set this as True if you would like to clip the given actions so that they conform to the declared boundaries of the action space. 
False 
kwargs 
Expected in the form of additional keyword arguments. These additional keyword arguments are passed to the superclass. 
{} 
Source code in evotorch/neuroevolution/net/vecrl.py
def __init__(
self,
env: Union[gym.Env],
*,
force_classic_api: bool = False,
discrete_to_continuous_act: bool = False,
clip_actions: bool = False,
**kwargs,
):
"""
`__init__(...)`: Initialize the TorchWrapper.
Args:
env: The gym environment to be wrapped.
force_classic_api: Set this as True if you would like to enable
the classic API. In the classic API, the `reset(...)` method
returns only the observation and the `step(...)` method
returns 4 elements (not 5).
discrete_to_continuous_act: When this is set as True and the
wrapped environment has a Discrete action space, this wrapper
will transform the action space to Box. A Discreteaction
environment with `n` actions will be converted to a Boxaction
environment where the action length is `n`.
The index of the largest value within the action vector will
be applied to the underlying environment.
clip_actions: Set this as True if you would like to clip the given
actions so that they conform to the declared boundaries of the
action space.
kwargs: Expected in the form of additional keyword arguments.
These additional keyword arguments are passed to the
superclass.
"""
super().__init__(env, **kwargs)
# Declare the variable that will store the array type of the underlying environment.
self.__array_type: Optional[str] = None
if hasattr(env, "single_observation_space"):
# If the underlying environment has the attribute "single_observation_space",
# then this is a vectorized environment.
self.__vectorized = True
# Get the observation and action spaces.
obs_space = env.single_observation_space
act_space = env.single_action_space
else:
# If the underlying environment has the attribute "single_observation_space",
# then this is a nonvectorized environment.
self.__vectorized = False
# Get the observation and action spaces.
obs_space = env.observation_space
act_space = env.action_space
# Ensure that the observation and action spaces are supported.
_must_be_supported_space(obs_space)
_must_be_supported_space(act_space)
# Store the choice of the user regarding "force_classic_api".
self.__force_classic_api = bool(force_classic_api)
if isinstance(act_space, Discrete) and discrete_to_continuous_act:
# The underlying action space is Discrete and `discrete_to_continuous_act` is given as True.
# Therefore, we convert the action space to continuous (to Box).
# Take the shape and the dtype of the discrete action space.
single_action_shape = (act_space.n,)
single_action_dtype = torch.from_numpy(np.array([], dtype=act_space.dtype)).dtype
# We store the integer dtype of the environment.
self.__discrete_dtype = single_action_dtype
if self.__vectorized:
# If the environment is vectorized, we declare the new `action_space` and the `single_action_space`
# for the enviornment.
action_shape = (env.num_envs,) + single_action_shape
self.single_action_space = Box(float("inf"), float("inf"), shape=single_action_shape, dtype=np.float32)
self.action_space = Box(float("inf"), float("inf"), shape=action_shape, dtype=np.float32)
else:
# If the environment is not vectorized, we declare the new `action_space` for the environment.
self.action_space = Box(float("inf"), float("inf"), shape=single_action_shape, dtype=np.float32)
else:
# This is the case where we do not transform the action space.
# The discrete dtype will not be used, so, we set it as None.
self.__discrete_dtype = None
if isinstance(act_space, Box) and clip_actions:
# If the action space is Box and the wrapper is configured to clip the actions, then we store the lower
# and the upper bounds for the actions.
self.__act_lb = torch.from_numpy(act_space.low)
self.__act_ub = torch.from_numpy(act_space.high)
else:
# If there will not be any action clipping, then we store the lower and the upper bounds as None.
self.__act_lb = None
self.__act_ub = None
reset(self, *args, **kwargs)
¶
Reset the environment
Source code in evotorch/neuroevolution/net/vecrl.py
def reset(self, *args, **kwargs):
"""Reset the environment"""
# Call the reset method of the wrapped environment.
reset_result = self.env.reset(*args, **kwargs)
if isinstance(reset_result, tuple):
# If we received a tuple of two elements, then we assume that this is the new gym API.
# We note that we received an info dictionary.
got_info = True
# We keep the received observation and info.
observation, info = reset_result
else:
# If we did not receive a tuple, then we assume that this is the old gym API.
# We note that we did not receive an info dictionary.
got_info = False
# We keep the received observation.
observation = reset_result
# We did not receive an info dictionary, so, we set it as an empty dictionary.
info = {}
# We understand the array type of the underlying environment from the first observation.
self.__infer_array_type(observation)
# Convert the observation to a PyTorch tensor.
observation = convert_to_torch(observation)
if self.__force_classic_api:
# If the option `force_classic_api` was set as True, then we only return the observation.
return observation
else:
# Here we handle the case where `force_classic_api` was set as False.
if got_info:
# If we got an additional info dictionary, we return it next to the observation.
return observation, info
else:
# If we did not get any info dictionary, we return only the observation.
return observation
step(self, action, *args, **kwargs)
¶
Take a step in the environment
Source code in evotorch/neuroevolution/net/vecrl.py
def step(self, action, *args, **kwargs):
"""Take a step in the environment"""
if self.__array_type is None:
# If the array type is not known yet, then probably `reset()` has not been called yet.
# We raise an error.
raise ValueError(
"Could not understand what type of array this environment works with."
" Perhaps the `reset()` method has not been called yet?"
)
if self.__discrete_dtype is not None:
# If the wrapped environment is discreteactioned, then we take the integer counterpart of the action.
action = torch.argmax(action, dim=1).to(dtype=self.__discrete_dtype)
if self.__act_lb is not None:
# The internal variable `__act_lb` having a value other than None means that the initialization argument
# `clip_actions` was given as True.
# Therefore, we clip the actions.
self.__act_lb = self.__act_lb.to(action.device)
self.__act_ub = self.__act_ub.to(action.device)
action = torch.max(action, self.__act_lb)
action = torch.min(action, self.__act_ub)
# Convert the action tensor to the expected array type of the underlying environment.
action = convert_from_torch(action, self.__array_type)
# Perform the step and get the result.
result = self.env.step(action, *args, **kwargs)
if not isinstance(result, tuple):
# If the `step(...)` method returned anything other than tuple, we raise an error.
raise TypeError(f"Expected a tuple as the result of the `step()` method, but received a {type(result)}")
if len(result) == 5:
# If the result is a tuple of 5 elements, then we note that we are using the new API.
using_new_api = True
# Take the observation, reward, two boolean variables done and done2 indicating that the episode(s)
# has/have ended, and additional info.
# `done` indicates whether or not the episode(s) reached terminal state(s).
# `done2` indicates whether or not the episode(s) got truncated because of the timestep limit.
observation, reward, done, done2, info = result
elif len(result) == 4:
# If the result is a tuple of 5 elements, then we note that we are not using the new API.
using_new_api = False
# Take the observation, reward, the done boolean flag, and additional info.
observation, reward, done, info = result
done2 = None
else:
raise ValueError(f"Unexpected number of elements were returned from step(): {len(result)}")
# Convert the observation, reward, and done variables to PyTorch tensors.
observation = convert_to_torch(observation)
reward = convert_to_torch(reward)
done = convert_to_torch_bool(done)
if done2 is not None:
done2 = convert_to_torch_bool(done2)
if self.__force_classic_api:
# This is the case where the initialization argument `force_classic_api` was set as True.
if done2 is not None:
# We combine the terminal state and truncation signals into a single boolean tensor indicating
# whether or not the episode(s) ended.
done = done  done2
# Return 4 elements, compatible with the classic gym API.
return observation, reward, done, info
else:
# This is the case where the initialization argument `force_classic_api` was set as False.
if using_new_api:
# If we are using the new API, then we return the 5element result.
return observation, reward, done, done2, info
else:
# If we are using the new API, then we return the 4element result.
return observation, reward, done, info
array_type(x, fallback=None)
¶
Get the type of an array as a string ("jax", "torch", or "numpy"). If the type of the array cannot be determined and a fallback is provided, then the fallback value will be returned.
Parameters:
Name  Type  Description  Default 

x 
Any 
The array whose type will be determined. 
required 
fallback 
Optional[str] 
Fallback value, as a string, which will be returned if the array type cannot be determined. 
None 
Returns:
Type  Description 

str 
The array type as a string ("jax", "torch", or "numpy"). 
Exceptions:
Type  Description 

TypeError 
if the array type cannot be determined and a fallback value is not provided. 
Source code in evotorch/neuroevolution/net/vecrl.py
def array_type(x: Any, fallback: Optional[str] = None) > str:
"""
Get the type of an array as a string ("jax", "torch", or "numpy").
If the type of the array cannot be determined and a fallback is provided,
then the fallback value will be returned.
Args:
x: The array whose type will be determined.
fallback: Fallback value, as a string, which will be returned if the
array type cannot be determined.
Returns:
The array type as a string ("jax", "torch", or "numpy").
Raises:
TypeError: if the array type cannot be determined and a fallback
value is not provided.
"""
if is_jax_array(x):
return "jax"
elif isinstance(x, torch.Tensor):
return "torch"
elif isinstance(x, np.ndarray):
return "numpy"
elif fallback is not None:
return fallback
else:
raise TypeError(f"The object has an unrecognized type: {type(x)}")
convert_from_torch(x, array_type)
¶
Convert the given PyTorch tensor to an array of the specified type.
Parameters:
Name  Type  Description  Default 

x 
Tensor 
The PyTorch array that will be converted. 
required 
array_type 
str 
Type to which the PyTorch tensor will be converted. Expected as one of these strings: "jax", "torch", "numpy". 
required 
Source code in evotorch/neuroevolution/net/vecrl.py
def convert_from_torch(x: torch.Tensor, array_type: str) > Any:
"""
Convert the given PyTorch tensor to an array of the specified type.
Args:
x: The PyTorch array that will be converted.
array_type: Type to which the PyTorch tensor will be converted.
Expected as one of these strings: "jax", "torch", "numpy".
Returns:
"""
if array_type == "torch":
return x
elif array_type == "jax":
return torch_to_jax(x)
elif array_type == "numpy":
return x.cpu().numpy()
else:
raise ValueError(f"Unrecognized array type: {array_type}")
convert_to_torch(x)
¶
Convert the given array to PyTorch tensor.
Parameters:
Name  Type  Description  Default 

x 
Any 
Array to be converted. Can be a JAX array, a numpy array, a PyTorch tensor (in which case the input tensor will be returned as it is) or any Iterable object. 
required 
Returns:
Type  Description 

Tensor 
The PyTorch counterpart of the given array. 
Source code in evotorch/neuroevolution/net/vecrl.py
def convert_to_torch(x: Any) > torch.Tensor:
"""
Convert the given array to PyTorch tensor.
Args:
x: Array to be converted. Can be a JAX array, a numpy array,
a PyTorch tensor (in which case the input tensor will be
returned as it is) or any Iterable object.
Returns:
The PyTorch counterpart of the given array.
"""
if isinstance(x, torch.Tensor):
return x
elif is_jax_array(x):
return jax_to_torch(x)
elif isinstance(x, np.ndarray):
return torch.from_numpy(x)
else:
return torch.as_tensor(x)
convert_to_torch_bool(x)
¶
Convert the given array to a PyTorch tensor of bools.
If the given object is an array of floating point numbers, then, values that are near to 0.0 (with a tolerance of 1e4) will be converted to False, and the others will be converted to True. If the given object is an array of integers, then zero values will be converted to False, and nonzero values will be converted to True. If the given object is an array of booleans, then no change will be made to those boolean values.
The given object can be a JAX array, a numpy array, or a PyTorch tensor. The result will always be a PyTorch tensor.
Parameters:
Name  Type  Description  Default 

x 
Any 
Array to be converted. 
required 
Returns:
Type  Description 

Tensor 
The array converted to a PyTorch tensor with its dtype set as bool. 
Source code in evotorch/neuroevolution/net/vecrl.py
def convert_to_torch_bool(x: Any) > torch.Tensor:
"""
Convert the given array to a PyTorch tensor of bools.
If the given object is an array of floating point numbers, then, values
that are near to 0.0 (with a tolerance of 1e4) will be converted to
False, and the others will be converted to True.
If the given object is an array of integers, then zero values will be
converted to False, and nonzero values will be converted to True.
If the given object is an array of booleans, then no change will be made
to those boolean values.
The given object can be a JAX array, a numpy array, or a PyTorch tensor.
The result will always be a PyTorch tensor.
Args:
x: Array to be converted.
Returns:
The array converted to a PyTorch tensor with its dtype set as bool.
"""
x = convert_to_torch(x)
if x.dtype == torch.bool:
pass # nothing to do
elif "float" in str(x.dtype):
x = torch.abs(x) > 1e4
else:
x = torch.as_tensor(x, dtype=torch.bool)
return x
make_brax_env(env_name, *, force_classic_api=False, num_envs=None, discrete_to_continuous_act=False, clip_actions=False, **kwargs)
¶
Make a brax environment and wrap it via TorchWrapper.
Parameters:
Name  Type  Description  Default 

env_name 
str 
Name of the brax environment, as string (e.g. "humanoid"). 
required 
force_classic_api 
bool 
Whether or not the classic gym API is to be used. 
False 
num_envs 
Optional[int] 
Batch size for the vectorized environment. 
None 
discrete_to_continuous_act 
bool 
Whether or not the the discrete action space of the environment is to be converted to a continuous one. This does nothing if the environment's action space is not discrete. 
False 
clip_actions 
bool 
Whether or not the actions should be explicitly clipped so that they stay within the declared action boundaries. 
False 
kwargs 
Expected in the form of additional keyword arguments, these are passed to the environment. 
{} 
Returns:
Type  Description 

TorchWrapper 
The brax environment, wrapped by TorchWrapper. 
Source code in evotorch/neuroevolution/net/vecrl.py
def make_brax_env(
env_name: str,
*,
force_classic_api: bool = False,
num_envs: Optional[int] = None,
discrete_to_continuous_act: bool = False,
clip_actions: bool = False,
**kwargs,
) > TorchWrapper:
"""
Make a brax environment and wrap it via TorchWrapper.
Args:
env_name: Name of the brax environment, as string (e.g. "humanoid").
force_classic_api: Whether or not the classic gym API is to be used.
num_envs: Batch size for the vectorized environment.
discrete_to_continuous_act: Whether or not the the discrete action
space of the environment is to be converted to a continuous one.
This does nothing if the environment's action space is not
discrete.
clip_actions: Whether or not the actions should be explicitly clipped
so that they stay within the declared action boundaries.
kwargs: Expected in the form of additional keyword arguments, these
are passed to the environment.
Returns:
The brax environment, wrapped by TorchWrapper.
"""
if brax is not None:
config = {}
config.update(kwargs)
if num_envs is not None:
config["batch_size"] = num_envs
env = brax.envs.create_gym_env(env_name, **config)
env = TorchWrapper(
env,
force_classic_api=force_classic_api,
discrete_to_continuous_act=discrete_to_continuous_act,
clip_actions=clip_actions,
)
return env
else:
_brax_is_missing()
make_gym_env(env_name, *, force_classic_api=False, num_envs=None, discrete_to_continuous_act=False, clip_actions=False, **kwargs)
¶
Make gym environments and wrap them via a SyncVectorEnv and a TorchWrapper.
Parameters:
Name  Type  Description  Default 

env_name 
str 
Name of the gym environment, as string (e.g. "Humanoidv4"). 
required 
force_classic_api 
bool 
Whether or not the classic gym API is to be used. 
False 
num_envs 
Optional[int] 
Batch size for the vectorized environment. 
None 
discrete_to_continuous_act 
bool 
Whether or not the the discrete action space of the environment is to be converted to a continuous one. This does nothing if the environment's action space is not discrete. 
False 
clip_actions 
bool 
Whether or not the actions should be explicitly clipped so that they stay within the declared action boundaries. 
False 
kwargs 
Expected in the form of additional keyword arguments, these are passed to the environment. 
{} 
Returns:
Type  Description 

TorchWrapper 
The gym environments, wrapped by a TorchWrapper. 
Source code in evotorch/neuroevolution/net/vecrl.py
def make_gym_env(
env_name: str,
*,
force_classic_api: bool = False,
num_envs: Optional[int] = None,
discrete_to_continuous_act: bool = False,
clip_actions: bool = False,
**kwargs,
) > TorchWrapper:
"""
Make gym environments and wrap them via a SyncVectorEnv and a TorchWrapper.
Args:
env_name: Name of the gym environment, as string (e.g. "Humanoidv4").
force_classic_api: Whether or not the classic gym API is to be used.
num_envs: Batch size for the vectorized environment.
discrete_to_continuous_act: Whether or not the the discrete action
space of the environment is to be converted to a continuous one.
This does nothing if the environment's action space is not
discrete.
clip_actions: Whether or not the actions should be explicitly clipped
so that they stay within the declared action boundaries.
kwargs: Expected in the form of additional keyword arguments, these
are passed to the environment.
Returns:
The gym environments, wrapped by a TorchWrapper.
"""
def make_the_env():
return gym.make(env_name, **kwargs)
env_fns = [make_the_env for _ in range(num_envs)]
vec_env = TorchWrapper(
SyncVectorEnv(env_fns),
force_classic_api=force_classic_api,
discrete_to_continuous_act=discrete_to_continuous_act,
clip_actions=clip_actions,
)
return vec_env
make_vector_env(env_name, *, force_classic_api=False, num_envs=None, discrete_to_continuous_act=False, clip_actions=False, **kwargs)
¶
Make a new vectorized environment and wrap it via TorchWrapper.
Parameters:
Name  Type  Description  Default 

env_name 
str 
Name of the gym environment, as string. If the string starts with "gym::" (e.g. "gym::Humanoidv4", etc.), then it is assumed that the target environment is a classical gym environment which will first be wrapped via a SyncVectorEnv and then via a TorchWrapper. If the string starts with "brax::" (e.g. "brax::humanoid", etc.), then it is assumed that the target environment is a brax environment which will be wrapped via TorchWrapper. If the string does not contain "::" at all (e.g. "Humanoidv4"), then it is assumed that the target environment is a classical gym environment. Therefore, "gym::Humanoidv4" and "Humanoidv4" are equivalent. 
required 
force_classic_api 
bool 
Whether or not the classic gym API is to be used. 
False 
num_envs 
Optional[int] 
Batch size for the vectorized environment. 
None 
discrete_to_continuous_act 
bool 
Whether or not the the discrete action space of the environment is to be converted to a continuous one. This does nothing if the environment's action space is not discrete. 
False 
clip_actions 
bool 
Whether or not the actions should be explicitly clipped so that they stay within the declared action boundaries. 
False 
kwargs 
Expected in the form of additional keyword arguments, these are passed to the environment. 
{} 
Returns:
Type  Description 

TorchWrapper 
The gym environments, wrapped by a TorchWrapper. 
Source code in evotorch/neuroevolution/net/vecrl.py
def make_vector_env(
env_name: str,
*,
force_classic_api: bool = False,
num_envs: Optional[int] = None,
discrete_to_continuous_act: bool = False,
clip_actions: bool = False,
**kwargs,
) > TorchWrapper:
"""
Make a new vectorized environment and wrap it via TorchWrapper.
Args:
env_name: Name of the gym environment, as string.
If the string starts with "gym::" (e.g. "gym::Humanoidv4", etc.),
then it is assumed that the target environment is a classical gym
environment which will first be wrapped via a SyncVectorEnv and
then via a TorchWrapper.
If the string starts with "brax::" (e.g. "brax::humanoid", etc.),
then it is assumed that the target environment is a brax
environment which will be wrapped via TorchWrapper.
If the string does not contain "::" at all (e.g. "Humanoidv4"),
then it is assumed that the target environment is a classical gym
environment. Therefore, "gym::Humanoidv4" and "Humanoidv4"
are equivalent.
force_classic_api: Whether or not the classic gym API is to be used.
num_envs: Batch size for the vectorized environment.
discrete_to_continuous_act: Whether or not the the discrete action
space of the environment is to be converted to a continuous one.
This does nothing if the environment's action space is not
discrete.
clip_actions: Whether or not the actions should be explicitly clipped
so that they stay within the declared action boundaries.
kwargs: Expected in the form of additional keyword arguments, these
are passed to the environment.
Returns:
The gym environments, wrapped by a TorchWrapper.
"""
env_parts = str(env_name).split("::", maxsplit=1)
if len(env_parts) == 0:
raise ValueError(f"Invalid value for `env_name`: {repr(env_name)}")
elif len(env_parts) == 1:
fn = make_gym_env
elif len(env_parts) == 2:
env_name = env_parts[1]
if env_parts[0] == "gym":
fn = make_gym_env
elif env_parts[0] == "brax":
fn = make_brax_env
else:
invalid_value = env_parts[0] + "::"
raise ValueError(
f"The argument `env_name` starts with {repr(invalid_value)}, implying that the environment is stored"
f" in a registry named {repr(env_parts[0])}."
f" However, the registry {repr(env_parts[0])} is not recognized."
f" Supported environment registries are: 'gym', 'brax'."
)
else:
assert False, "Unexpected value received from len(env_parts)"
return fn(
env_name,
force_classic_api=force_classic_api,
num_envs=num_envs,
discrete_to_continuous_act=discrete_to_continuous_act,
clip_actions=clip_actions,
**kwargs,
)
reset_tensors(x, indices)
¶
Reset the specified regions of the given tensor(s) as 0.
Note that the resetting is performed inplace, which means, the provided tensors are modified.
The regions are determined by the argument indices
, which can be a sequence of booleans (in which case it is
interpreted as a mask), or a sequence of integers (in which case it is interpreted as the list of indices).
For example, let us imagine that we have the following tensor:
import torch
x = torch.tensor(
[
[0, 1, 2, 3],
[4, 5, 6, 7],
[8, 9, 10, 11],
[12, 13, 14, 15],
],
dtype=torch.float32,
)
If we wish to reset the rows with indices 0 and 2, we could use:
The new value of x
would then be:
torch.tensor(
[
[0, 0, 0, 0],
[4, 5, 6, 7],
[0, 0, 0, 0],
[12, 13, 14, 15],
],
dtype=torch.float32,
)
The first argument does not have to be a single tensor. Instead, it can be a container (i.e. a dictionarylike object or an iterable) that stores tensors. In this case, each tensor stored by the container will be subject to resetting. In more details, each tensor within the iterable(s) and each tensor within the value part of the dictionarylike object(s) will be reset.
As an example, let us assume that we have the following collection:
a = torch.tensor(
[
[0, 1],
[2, 3],
[4, 5],
],
dtype=torch.float32,
)
b = torch.tensor(
[
[0, 10, 20],
[30, 40, 50],
[60, 70, 80],
],
dtype=torch.float32,
)
c = torch.tensor(
[
[100],
[200],
[300],
],
dtype=torch.float32,
)
d = torch.tensor([1, 2, 3], dtype=torch.float32)
my_tensors = [a, {"1": b, "2": (c, d)}]
To clear the regions with indices, e.g, (1, 2), we could do:
and the result would be:
>>> print(a)
torch.tensor(
[
[0, 1],
[0, 0],
[0, 0],
],
dtype=torch.float32,
)
>>> print(b)
torch.tensor(
[
[0, 10, 20],
[0, 0, 0],
[0, 0, 0],
],
dtype=torch.float32,
)
>>> print(c)
c = torch.tensor(
[
[100],
[0],
[0],
],
dtype=torch.float32,
)
>>> print(d)
torch.tensor([1, 0, 0], dtype=torch.float32)
Parameters:
Name  Type  Description  Default 

x 
Any 
A tensor or a collection of tensors, whose values are subject to resetting. 
required 
indices 
Union[int, Iterable] 
A sequence of integers or booleans, specifying which regions of the tensor(s) will be reset. 
required 
Source code in evotorch/neuroevolution/net/vecrl.py
def reset_tensors(x: Any, indices: MaskOrIndices):
"""
Reset the specified regions of the given tensor(s) as 0.
Note that the resetting is performed inplace, which means, the provided tensors are modified.
The regions are determined by the argument `indices`, which can be a sequence of booleans (in which case it is
interpreted as a mask), or a sequence of integers (in which case it is interpreted as the list of indices).
For example, let us imagine that we have the following tensor:
```python
import torch
x = torch.tensor(
[
[0, 1, 2, 3],
[4, 5, 6, 7],
[8, 9, 10, 11],
[12, 13, 14, 15],
],
dtype=torch.float32,
)
```
If we wish to reset the rows with indices 0 and 2, we could use:
```python
reset_tensors(x, [0, 2])
```
The new value of `x` would then be:
```
torch.tensor(
[
[0, 0, 0, 0],
[4, 5, 6, 7],
[0, 0, 0, 0],
[12, 13, 14, 15],
],
dtype=torch.float32,
)
```
The first argument does not have to be a single tensor.
Instead, it can be a container (i.e. a dictionarylike object or an iterable) that stores tensors.
In this case, each tensor stored by the container will be subject to resetting.
In more details, each tensor within the iterable(s) and each tensor within the value part of the dictionarylike
object(s) will be reset.
As an example, let us assume that we have the following collection:
```python
a = torch.tensor(
[
[0, 1],
[2, 3],
[4, 5],
],
dtype=torch.float32,
)
b = torch.tensor(
[
[0, 10, 20],
[30, 40, 50],
[60, 70, 80],
],
dtype=torch.float32,
)
c = torch.tensor(
[
[100],
[200],
[300],
],
dtype=torch.float32,
)
d = torch.tensor([1, 2, 3], dtype=torch.float32)
my_tensors = [a, {"1": b, "2": (c, d)}]
```
To clear the regions with indices, e.g, (1, 2), we could do:
```python
reset_tensors(my_tensors, [1, 2])
```
and the result would be:
```
>>> print(a)
torch.tensor(
[
[0, 1],
[0, 0],
[0, 0],
],
dtype=torch.float32,
)
>>> print(b)
torch.tensor(
[
[0, 10, 20],
[0, 0, 0],
[0, 0, 0],
],
dtype=torch.float32,
)
>>> print(c)
c = torch.tensor(
[
[100],
[0],
[0],
],
dtype=torch.float32,
)
>>> print(d)
torch.tensor([1, 0, 0], dtype=torch.float32)
```
Args:
x: A tensor or a collection of tensors, whose values are subject to resetting.
indices: A sequence of integers or booleans, specifying which regions of the tensor(s) will be reset.
"""
if isinstance(x, torch.Tensor):
# If the first argument is a tensor, then we clear it according to the indices we received.
x[indices] = 0
elif isinstance(x, (str, bytes, bytearray)):
# str, bytes, and bytearray are the types of `Iterable` that we do not wish to process.
# Therefore, we explicitly add a condition for them here, and explicitly state that nothing should be done
# when instances of them are encountered.
pass
elif isinstance(x, Mapping):
# If the first argument is a Mapping (i.e. a dictionarylike object), then, for each value part of the
# Mapping instance, we call this function itself.
for key, value in x.items():
reset_tensors(value, indices)
elif isinstance(x, Iterable):
# If the first argument is an Iterable (e.g. a list, a tuple, etc.), then, for each value contained by this
# Iterable instance, we call this function itself.
for value in x:
reset_tensors(value, indices)