Delete initialization.py
Browse files- initialization.py +0 -95
initialization.py
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import math
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from typing import Optional, Union
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import torch
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import torch.nn as nn
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from .config import InitFnType, ModelConfig
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from .util import StrEnum
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__all__ = ["init_weights", "ModuleType"]
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class ModuleType(StrEnum):
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in_module = "in"
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out_module = "out"
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emb = "emb"
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final_out = "final_out"
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def init_weights(
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config: ModelConfig,
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module: Union[nn.Linear, nn.Embedding],
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d: Optional[int] = None,
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layer_id: Optional[int] = None,
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std_factor: float = 1.0,
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type_of_module: Optional[ModuleType] = None,
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) -> None:
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"""
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Initialize weights of a linear or embedding module.
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:param config: The model config.
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:param module: The linear or embedding submodule to initialize.
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:param d: The effective input dimensionality of the weights. This could be smaller than the actual dimensions
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for fused layers.
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:param layer_id: When set, the standard deviation for the "mitchell" method will be adjusted by
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``1 / sqrt(2 * (layer_id + 1))``.
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"""
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d = d if d is not None else config.d_model
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if config.init_fn == InitFnType.normal:
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std = config.init_std * std_factor
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if config.init_cutoff_factor is not None:
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cutoff_value = config.init_cutoff_factor * std
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nn.init.trunc_normal_(module.weight, mean=0.0, std=std, a=-cutoff_value, b=cutoff_value)
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else:
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nn.init.normal_(module.weight, mean=0.0, std=std)
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elif config.init_fn == InitFnType.mitchell:
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std = std_factor / math.sqrt(d)
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if layer_id is not None:
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std = std / math.sqrt(2 * (layer_id + 1))
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nn.init.trunc_normal_(module.weight, mean=0.0, std=std, a=-3 * std, b=3 * std)
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elif config.init_fn == InitFnType.kaiming_normal:
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nn.init.kaiming_normal_(module.weight, nonlinearity="relu")
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elif config.init_fn == InitFnType.fan_in:
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std = std_factor / math.sqrt(d)
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nn.init.normal_(module.weight, mean=0.0, std=std)
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elif config.init_fn == InitFnType.full_megatron:
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if type_of_module is None:
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raise RuntimeError(f"When using the {InitFnType.full_megatron} init, every module must have a type.")
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cutoff_factor = config.init_cutoff_factor
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if cutoff_factor is None:
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cutoff_factor = 3
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if type_of_module == ModuleType.in_module:
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# for att_proj (same as QKV), ff_proj
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std = config.init_std
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elif type_of_module == ModuleType.out_module:
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# for attn_out, ff_out
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std = config.init_std / math.sqrt(2.0 * config.n_layers)
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elif type_of_module == ModuleType.emb:
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# positional embeddings (wpe)
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# token embeddings (wte)
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std = config.init_std
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elif type_of_module == ModuleType.final_out:
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# final output (ff_out)
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std = config.d_model**-0.5
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else:
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raise RuntimeError(f"Unknown module type '{type_of_module}'")
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nn.init.trunc_normal_(
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module.weight,
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mean=0.0,
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std=std,
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a=-cutoff_factor * std,
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b=cutoff_factor * std,
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)
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else:
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raise NotImplementedError(config.init_fn)
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if isinstance(module, nn.Linear):
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if module.bias is not None:
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nn.init.zeros_(module.bias)
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if config.init_fn == InitFnType.normal and getattr(module, "_is_residual", False):
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with torch.no_grad():
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module.weight.div_(math.sqrt(2 * config.n_layers))
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