176 lines
6.7 KiB
Python
176 lines
6.7 KiB
Python
import contextlib
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from typing import Generator
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import warnings
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from torch._C import default_generator
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import torch
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def set_rng_state(new_state: torch.Tensor) -> None:
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r"""Sets the random number generator state.
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.. note: This function only works for CPU. For CUDA, please use
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torch.manual_seed(seed), which works for both CPU and CUDA.
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Args:
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new_state (torch.ByteTensor): The desired state
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"""
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default_generator.set_state(new_state)
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def get_rng_state() -> torch.Tensor:
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r"""Returns the random number generator state as a `torch.ByteTensor`."""
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return default_generator.get_state()
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def manual_seed(seed) -> torch._C.Generator:
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r"""Sets the seed for generating random numbers. Returns a
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`torch.Generator` object.
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Args:
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seed (int): The desired seed. Value must be within the inclusive range
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`[-0x8000_0000_0000_0000, 0xffff_ffff_ffff_ffff]`. Otherwise, a RuntimeError
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is raised. Negative inputs are remapped to positive values with the formula
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`0xffff_ffff_ffff_ffff + seed`.
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"""
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seed = int(seed)
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import torch.cuda
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if not torch.cuda._is_in_bad_fork():
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torch.cuda.manual_seed_all(seed)
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import torch.mps
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if not torch.mps._is_in_bad_fork():
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torch.mps.manual_seed(seed)
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import torch.xpu
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if not torch.xpu._is_in_bad_fork():
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torch.xpu.manual_seed_all(seed)
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_seed_custom_device(seed)
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return default_generator.manual_seed(seed)
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def seed() -> int:
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r"""Sets the seed for generating random numbers to a non-deterministic
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random number. Returns a 64 bit number used to seed the RNG.
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"""
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seed = default_generator.seed()
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import torch.cuda
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if not torch.cuda._is_in_bad_fork():
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torch.cuda.manual_seed_all(seed)
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import torch.mps
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if not torch.mps._is_in_bad_fork():
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torch.mps.manual_seed(seed)
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import torch.xpu
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if not torch.xpu._is_in_bad_fork():
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torch.xpu.manual_seed_all(seed)
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_seed_custom_device(seed)
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return seed
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def _seed_custom_device(seed) -> None:
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r"""Sets the seed to generate random numbers for custom device.
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Args:
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seed (int): The desired seed.
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See [Note: support the custom device with privateuse1]
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"""
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seed = int(seed)
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custom_backend_name = torch._C._get_privateuse1_backend_name()
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if hasattr(torch, custom_backend_name):
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custom_device_mod = getattr(torch, custom_backend_name)
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_bad_fork_name = "_is_in_bad_fork"
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_seed_all_name = "manual_seed_all"
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if hasattr(custom_device_mod, _bad_fork_name) and hasattr(custom_device_mod, _seed_all_name):
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if not getattr(custom_device_mod, _bad_fork_name)():
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getattr(custom_device_mod, _seed_all_name)(seed)
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else:
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message = f"Set seed for `{custom_backend_name}` device does not take effect, please add API's "
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message += f"`{_bad_fork_name}` and `{_seed_all_name}` to `{custom_backend_name}` device module."
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warnings.warn(message, UserWarning, stacklevel=3)
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def initial_seed() -> int:
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r"""Returns the initial seed for generating random numbers as a
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Python `long`.
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"""
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return default_generator.initial_seed()
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_fork_rng_warned_already = False
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@contextlib.contextmanager
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def fork_rng(devices=None, enabled=True, _caller="fork_rng", _devices_kw="devices", device_type="cuda") -> Generator:
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"""
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Forks the RNG, so that when you return, the RNG is reset
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to the state that it was previously in.
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Args:
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devices (iterable of Device IDs): devices for which to fork
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the RNG. CPU RNG state is always forked. By default, :meth:`fork_rng` operates
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on all devices, but will emit a warning if your machine has a lot
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of devices, since this function will run very slowly in that case.
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If you explicitly specify devices, this warning will be suppressed
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enabled (bool): if ``False``, the RNG is not forked. This is a convenience
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argument for easily disabling the context manager without having
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to delete it and unindent your Python code under it.
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deivce_type (str): device type str, default is `cuda`. As for custom device,
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see details in [Note: support the custom device with privateuse1]
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"""
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device_type = torch.device(device_type).type
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device_mod = getattr(torch, device_type, None)
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if device_mod is None:
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raise RuntimeError(f"torch has no module of `{device_type}`, you should register " +
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"a module by `torch._register_device_module`.")
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global _fork_rng_warned_already
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# Internal arguments:
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# _caller: the function which called fork_rng, which the user used
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# _devices_kw: the devices keyword of _caller
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if not enabled:
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yield
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return
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if devices is None:
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num_devices = device_mod.device_count()
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if num_devices > 1 and not _fork_rng_warned_already:
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message = (f"{device_type.upper()} reports that you have {num_devices} available devices, and "
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f"you have used {_caller} without explicitly specifying which devices are being used. "
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f"For safety, we initialize *every* {device_type.upper()} device by default, which can "
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f"be quite slow if you have a lot of {device_type.upper()}s. If you know that you are only"
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f" making use of a few {device_type.upper()} devices, set the environment variable "
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f"{device_type.upper()}_VISIBLE_DEVICES or the '{_devices_kw}' keyword argument of {_caller} "
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"with the set of devices you are actually using. For example, if you are using CPU only, "
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"set device.upper()_VISIBLE_DEVICES= or devices=[]; if you are using device 0 only, "
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f"set {device_type.upper()}_VISIBLE_DEVICES=0 or devices=[0]. To initialize all devices "
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f"and suppress this warning, set the '{_devices_kw}' keyword argument to "
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f"`range(torch.{device_type}.device_count())`.")
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warnings.warn(message)
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_fork_rng_warned_already = True
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devices = list(range(num_devices))
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else:
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# Protect against user passing us a generator; we need to traverse this
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# multiple times but a generator will be exhausted upon first traversal
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devices = list(devices)
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cpu_rng_state = torch.get_rng_state()
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device_rng_states = [device_mod.get_rng_state(device) for device in devices]
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try:
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yield
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finally:
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torch.set_rng_state(cpu_rng_state)
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for device, device_rng_state in zip(devices, device_rng_states):
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device_mod.set_rng_state(device_rng_state, device)
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