Run in Google Colab# Copyright (c) Meta Platforms, Inc. and affiliates. All rights reserved.
Implicitron's components are all based on a unified hierarchical configuration system. This allows configurable variables and all defaults to be defined separately for each new component. All configs relevant to an experiment are then automatically composed into a single configuration file that fully specifies the experiment. An especially important feature is extension points where users can insert their own sub-classes of Implicitron's base components.
The file which defines this system is here in the PyTorch3D repo. The Implicitron volumes tutorial contains a simple example of using the config system. This tutorial provides detailed hands-on experience in using and modifying Implicitron's configurable components.
Ensure torch and torchvision are installed. If pytorch3d is not installed, install it using the following cell:
import os
import sys
import torch
need_pytorch3d=False
try:
import pytorch3d
except ModuleNotFoundError:
need_pytorch3d=True
if need_pytorch3d:
if torch.__version__.startswith("2.1.") and sys.platform.startswith("linux"):
# We try to install PyTorch3D via a released wheel.
pyt_version_str=torch.__version__.split("+")[0].replace(".", "")
version_str="".join([
f"py3{sys.version_info.minor}_cu",
torch.version.cuda.replace(".",""),
f"_pyt{pyt_version_str}"
])
!pip install fvcore iopath
!pip install --no-index --no-cache-dir pytorch3d -f https://dl.fbaipublicfiles.com/pytorch3d/packaging/wheels/{version_str}/download.html
else:
# We try to install PyTorch3D from source.
!pip install 'git+https://github.com/facebookresearch/pytorch3d.git@stable'
Ensure omegaconf is installed. If not, run this cell. (It should not be necessary to restart the runtime.)
!pip install omegaconf
from dataclasses import dataclass
from typing import Optional, Tuple
import torch
from omegaconf import DictConfig, OmegaConf
from pytorch3d.implicitron.tools.config import (
Configurable,
ReplaceableBase,
expand_args_fields,
get_default_args,
registry,
run_auto_creation,
)
Type hints give a taxonomy of types in Python. Dataclasses let you create a class based on a list of members which have names, types and possibly default values. The __init__ function is created automatically, and calls a __post_init__ function if present as a final step. For example
@dataclass
class MyDataclass:
a: int
b: int = 8
c: Optional[Tuple[int, ...]] = None
def __post_init__(self):
print(f"created with a = {self.a}")
self.d = 2 * self.b
my_dataclass_instance = MyDataclass(a=18)
assert my_dataclass_instance.d == 16
👷 Note that the dataclass decorator here is function which modifies the definition of the class itself.
It runs immediately after the definition.
Our config system requires that implicitron library code contains classes whose modified versions need to be aware of user-defined implementations.
Therefore we need the modification of the class to be delayed. We don't use a decorator.
dc = DictConfig({"a": 2, "b": True, "c": None, "d": "hello"})
assert dc.a == dc["a"] == 2
OmegaConf has a serialization to and from yaml. The Hydra library relies on this for its configuration files.
print(OmegaConf.to_yaml(dc))
assert OmegaConf.create(OmegaConf.to_yaml(dc)) == dc
OmegaConf.structured provides a DictConfig from a dataclass or instance of a dataclass. Unlike a normal DictConfig, it is type-checked and only known keys can be added.
structured = OmegaConf.structured(MyDataclass)
assert isinstance(structured, DictConfig)
print(structured)
print()
print(OmegaConf.to_yaml(structured))
structured knows it is missing a value for a.
Such an object has members compatible with the dataclass, so an initialisation can be performed as follows.
structured.a = 21
my_dataclass_instance2 = MyDataclass(**structured)
print(my_dataclass_instance2)
You can also call OmegaConf.structured on an instance.
structured_from_instance = OmegaConf.structured(my_dataclass_instance)
my_dataclass_instance3 = MyDataclass(**structured_from_instance)
print(my_dataclass_instance3)
We provide functions which are equivalent to OmegaConf.structured but support more features.
To achieve the above using our functions, the following is used.
Note that we indicate configurable classes using a special base class Configurable, not a decorator.
class MyConfigurable(Configurable):
a: int
b: int = 8
c: Optional[Tuple[int, ...]] = None
def __post_init__(self):
print(f"created with a = {self.a}")
self.d = 2 * self.b
# The expand_args_fields function modifies the class like @dataclasses.dataclass.
# If it has not been called on a Configurable object before it has been instantiated, it will
# be called automatically.
expand_args_fields(MyConfigurable)
my_configurable_instance = MyConfigurable(a=18)
assert my_configurable_instance.d == 16
# get_default_args also calls expand_args_fields automatically
our_structured = get_default_args(MyConfigurable)
assert isinstance(our_structured, DictConfig)
print(OmegaConf.to_yaml(our_structured))
our_structured.a = 21
print(MyConfigurable(**our_structured))
Our system allows Configurable classes to contain each other.
One thing to remember: add a call to run_auto_creation in __post_init__.
class Inner(Configurable):
a: int = 8
b: bool = True
c: Tuple[int, ...] = (2, 3, 4, 6)
class Outer(Configurable):
inner: Inner
x: str = "hello"
xx: bool = False
def __post_init__(self):
run_auto_creation(self)
outer_dc = get_default_args(Outer)
print(OmegaConf.to_yaml(outer_dc))
outer = Outer(**outer_dc)
assert isinstance(outer, Outer)
assert isinstance(outer.inner, Inner)
print(vars(outer))
print(outer.inner)
Note how inner_args is an extra member of outer. run_auto_creation(self) is equivalent to
self.inner = Inner(**self.inner_args)If a class uses ReplaceableBase as a base class instead of Configurable, we call it a replaceable.
It indicates that it is designed for child classes to use in its place.
We might use NotImplementedError to indicate functionality which subclasses are expected to implement.
The system maintains a global registry containing subclasses of each ReplaceableBase.
The subclasses register themselves with it with a decorator.
A configurable class (i.e. a class which uses our system, i.e. a child of Configurable or ReplaceableBase) which contains a ReplaceableBase must also
contain a corresponding class_type field of type str which indicates which concrete child class to use.
class InnerBase(ReplaceableBase):
def say_something(self):
raise NotImplementedError
@registry.register
class Inner1(InnerBase):
a: int = 1
b: str = "h"
def say_something(self):
print("hello from an Inner1")
@registry.register
class Inner2(InnerBase):
a: int = 2
def say_something(self):
print("hello from an Inner2")
class Out(Configurable):
inner: InnerBase
inner_class_type: str = "Inner1"
x: int = 19
def __post_init__(self):
run_auto_creation(self)
def talk(self):
self.inner.say_something()
Out_dc = get_default_args(Out)
print(OmegaConf.to_yaml(Out_dc))
Out_dc.inner_class_type = "Inner2"
out = Out(**Out_dc)
print(out.inner)
out.talk()
Note in this case there are many args members. It is usually fine to ignore them in the code. They are needed for the config.
print(vars(out))
class MyLinear(torch.nn.Module, Configurable):
d_in: int = 2
d_out: int = 200
def __post_init__(self):
super().__init__()
self.linear = torch.nn.Linear(in_features=self.d_in, out_features=self.d_out)
def forward(self, x):
return self.linear.forward(x)
my_linear = MyLinear()
input = torch.zeros(2)
output = my_linear(input)
print("output shape:", output.shape)
my_linear has all the usual features of a Module.
E.g. it can be saved and loaded with torch.save and torch.load.
It has parameters:
for name, value in my_linear.named_parameters():
print(name, value.shape)
Let's say I am using a library with Out like in section 5 but I want to implement my own child of InnerBase.
All I need to do is register its definition, but I need to do this before expand_args_fields is explicitly or implicitly called on Out.
@registry.register
class UserImplementedInner(InnerBase):
a: int = 200
def say_something(self):
print("hello from the user")
At this point, we need to redefine the class Out. Otherwise if it has already been expanded without UserImplementedInner, then the following would not work, because the implementations known to a class are fixed when it is expanded.
If you are running experiments from a script, the thing to remember here is that you must import your own modules, which register your own implementations, before you use the library classes.
class Out(Configurable):
inner: InnerBase
inner_class_type: str = "Inner1"
x: int = 19
def __post_init__(self):
run_auto_creation(self)
def talk(self):
self.inner.say_something()
out2 = Out(inner_class_type="UserImplementedInner")
print(out2.inner)
Let's look what needs to happen if we have a subcomponent which we make pluggable, to allow users to supply their own.
class SubComponent(Configurable):
x: float = 0.25
def apply(self, a: float) -> float:
return a + self.x
class LargeComponent(Configurable):
repeats: int = 4
subcomponent: SubComponent
def __post_init__(self):
run_auto_creation(self)
def apply(self, a: float) -> float:
for _ in range(self.repeats):
a = self.subcomponent.apply(a)
return a
large_component = LargeComponent()
assert large_component.apply(3) == 4
print(OmegaConf.to_yaml(LargeComponent))
Made generic:
class SubComponentBase(ReplaceableBase):
def apply(self, a: float) -> float:
raise NotImplementedError
@registry.register
class SubComponent(SubComponentBase):
x: float = 0.25
def apply(self, a: float) -> float:
return a + self.x
class LargeComponent(Configurable):
repeats: int = 4
subcomponent: SubComponentBase
subcomponent_class_type: str = "SubComponent"
def __post_init__(self):
run_auto_creation(self)
def apply(self, a: float) -> float:
for _ in range(self.repeats):
a = self.subcomponent.apply(a)
return a
large_component = LargeComponent()
assert large_component.apply(3) == 4
print(OmegaConf.to_yaml(LargeComponent))
The following things had to change:
@registry.register decoration and had its base class changed to the new one.subcomponent_class_type was added as a member of the outer class.subcomponent_args had to be changed to subcomponent_SubComponent_args.__post_init__ or not calling run_auto_creation in it. subcomponent_class_type = "SubComponent" subcomponent_class_type: str = "SubComponent"