File size: 12,558 Bytes
5b3c5ad |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 |
import math
import warnings
from collections.abc import Sequence
from functools import partial
from typing import Optional, Tuple, Union
import torch
from torch import nn
from .norm import NORM_CLASS_REGISTRY
def torch_default_param_init_fn_(module: nn.Module, verbose: int=0, **kwargs):
del kwargs
if verbose > 1:
warnings.warn(f"Initializing network using module's reset_parameters attribute")
if hasattr(module, 'reset_parameters'):
module.reset_parameters()
def fused_init_helper_(module: nn.Module, init_fn_):
_fused = getattr(module, '_fused', None)
if _fused is None:
raise RuntimeError(f'Internal logic error')
(dim, splits) = _fused
splits = (0, *splits, module.weight.size(dim))
for (s, e) in zip(splits[:-1], splits[1:]):
slice_indices = [slice(None)] * module.weight.ndim
slice_indices[dim] = slice(s, e)
init_fn_(module.weight[slice_indices])
def generic_param_init_fn_(module: nn.Module, init_fn_, n_layers: int, d_model: Optional[int]=None, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, verbose: int=0, **kwargs):
del kwargs
if verbose > 1:
warnings.warn(f'If model has bias parameters they are initialized to 0.')
init_div_is_residual = init_div_is_residual
if init_div_is_residual is False:
div_is_residual = 1.0
elif init_div_is_residual is True:
div_is_residual = math.sqrt(2 * n_layers)
elif isinstance(init_div_is_residual, float) or isinstance(init_div_is_residual, int):
div_is_residual = init_div_is_residual
elif isinstance(init_div_is_residual, str) and init_div_is_residual.isnumeric():
div_is_residual = float(init_div_is_residual)
else:
div_is_residual = 1.0
raise ValueError(f'Expected init_div_is_residual to be boolean or numeric, got {init_div_is_residual}')
if init_div_is_residual is not False:
if verbose > 1:
warnings.warn(f'Initializing _is_residual layers then dividing them by {div_is_residual:.3f}. ' + f'Set `init_div_is_residual: false` in init config to disable this.')
if isinstance(module, nn.Linear):
if hasattr(module, '_fused'):
fused_init_helper_(module, init_fn_)
else:
init_fn_(module.weight)
if module.bias is not None:
torch.nn.init.zeros_(module.bias)
if init_div_is_residual is not False and getattr(module, '_is_residual', False):
with torch.no_grad():
module.weight.div_(div_is_residual)
elif isinstance(module, nn.Embedding):
if emb_init_std is not None:
std = emb_init_std
if std == 0:
warnings.warn(f'Embedding layer initialized to 0.')
emb_init_fn_ = partial(torch.nn.init.normal_, mean=0.0, std=std)
if verbose > 1:
warnings.warn(f'Embedding layer initialized using normal distribution with mean=0 and std={std!r}.')
elif emb_init_uniform_lim is not None:
lim = emb_init_uniform_lim
if isinstance(lim, Sequence):
if len(lim) > 2:
raise ValueError(f'Uniform init requires a min and a max limit. User input: {lim}.')
if lim[0] == lim[1]:
warnings.warn(f'Embedding layer initialized to {lim[0]}.')
else:
if lim == 0:
warnings.warn(f'Embedding layer initialized to 0.')
lim = [-lim, lim]
(a, b) = lim
emb_init_fn_ = partial(torch.nn.init.uniform_, a=a, b=b)
if verbose > 1:
warnings.warn(f'Embedding layer initialized using uniform distribution in range {lim}.')
else:
emb_init_fn_ = init_fn_
emb_init_fn_(module.weight)
elif isinstance(module, tuple(set(NORM_CLASS_REGISTRY.values()))):
if verbose > 1:
warnings.warn(f'Norm weights are set to 1. If norm layer has a bias it is initialized to 0.')
if hasattr(module, 'weight') and module.weight is not None:
torch.nn.init.ones_(module.weight)
if hasattr(module, 'bias') and module.bias is not None:
torch.nn.init.zeros_(module.bias)
elif isinstance(module, nn.MultiheadAttention):
if module._qkv_same_embed_dim:
assert module.in_proj_weight is not None
assert module.q_proj_weight is None and module.k_proj_weight is None and (module.v_proj_weight is None)
assert d_model is not None
_d = d_model
splits = (0, _d, 2 * _d, 3 * _d)
for (s, e) in zip(splits[:-1], splits[1:]):
init_fn_(module.in_proj_weight[s:e])
else:
assert module.q_proj_weight is not None and module.k_proj_weight is not None and (module.v_proj_weight is not None)
assert module.in_proj_weight is None
init_fn_(module.q_proj_weight)
init_fn_(module.k_proj_weight)
init_fn_(module.v_proj_weight)
if module.in_proj_bias is not None:
torch.nn.init.zeros_(module.in_proj_bias)
if module.bias_k is not None:
torch.nn.init.zeros_(module.bias_k)
if module.bias_v is not None:
torch.nn.init.zeros_(module.bias_v)
init_fn_(module.out_proj.weight)
if init_div_is_residual is not False and getattr(module.out_proj, '_is_residual', False):
with torch.no_grad():
module.out_proj.weight.div_(div_is_residual)
if module.out_proj.bias is not None:
torch.nn.init.zeros_(module.out_proj.bias)
else:
for _ in module.parameters(recurse=False):
raise NotImplementedError(f'{module.__class__.__name__} parameters are not initialized by param_init_fn.')
def _normal_init_(std, mean=0.0):
return partial(torch.nn.init.normal_, mean=mean, std=std)
def _normal_param_init_fn_(module: nn.Module, std: float, n_layers: int, d_model: Optional[int]=None, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, verbose: int=0, **kwargs):
del kwargs
init_fn_ = _normal_init_(std=std)
if verbose > 1:
warnings.warn(f'Using torch.nn.init.normal_ init fn mean=0.0, std={std}')
generic_param_init_fn_(module=module, init_fn_=init_fn_, d_model=d_model, n_layers=n_layers, init_div_is_residual=init_div_is_residual, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
def baseline_param_init_fn_(module: nn.Module, init_std: float, n_layers: int, d_model: Optional[int]=None, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, verbose: int=0, **kwargs):
del kwargs
if init_std is None:
raise ValueError("You must set model.init_config['init_std'] to a float value to use the default initialization scheme.")
_normal_param_init_fn_(module=module, std=init_std, d_model=d_model, n_layers=n_layers, init_div_is_residual=init_div_is_residual, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
def small_param_init_fn_(module: nn.Module, n_layers: int, d_model: int, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, verbose: int=0, **kwargs):
del kwargs
std = math.sqrt(2 / (5 * d_model))
_normal_param_init_fn_(module=module, std=std, d_model=d_model, n_layers=n_layers, init_div_is_residual=init_div_is_residual, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
def neox_param_init_fn_(module: nn.Module, n_layers: int, d_model: int, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, verbose: int=0, **kwargs):
"""From section 2.3.1 of GPT-NeoX-20B:
An Open-Source AutoregressiveLanguage Model — Black et. al. (2022)
see https://github.com/EleutherAI/gpt-neox/blob/9610391ab319403cef079b438edd016a2443af54/megatron/model/init_functions.py#L151
and https://github.com/EleutherAI/gpt-neox/blob/main/megatron/model/transformer.py
"""
del kwargs
residual_div = n_layers / math.sqrt(10)
if verbose > 1:
warnings.warn(f'setting init_div_is_residual to {residual_div}')
small_param_init_fn_(module=module, d_model=d_model, n_layers=n_layers, init_div_is_residual=residual_div, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
def kaiming_uniform_param_init_fn_(module: nn.Module, n_layers: int, d_model: Optional[int]=None, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, init_gain: float=0, fan_mode: str='fan_in', init_nonlinearity: str='leaky_relu', verbose: int=0, **kwargs):
del kwargs
if verbose > 1:
warnings.warn(f'Using nn.init.kaiming_uniform_ init fn with parameters: ' + f'a={init_gain}, mode={fan_mode}, nonlinearity={init_nonlinearity}')
kaiming_uniform_ = partial(nn.init.kaiming_uniform_, a=init_gain, mode=fan_mode, nonlinearity=init_nonlinearity)
generic_param_init_fn_(module=module, init_fn_=kaiming_uniform_, d_model=d_model, n_layers=n_layers, init_div_is_residual=init_div_is_residual, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
def kaiming_normal_param_init_fn_(module: nn.Module, n_layers: int, d_model: Optional[int]=None, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, init_gain: float=0, fan_mode: str='fan_in', init_nonlinearity: str='leaky_relu', verbose: int=0, **kwargs):
del kwargs
if verbose > 1:
warnings.warn(f'Using nn.init.kaiming_normal_ init fn with parameters: ' + f'a={init_gain}, mode={fan_mode}, nonlinearity={init_nonlinearity}')
kaiming_normal_ = partial(torch.nn.init.kaiming_normal_, a=init_gain, mode=fan_mode, nonlinearity=init_nonlinearity)
generic_param_init_fn_(module=module, init_fn_=kaiming_normal_, d_model=d_model, n_layers=n_layers, init_div_is_residual=init_div_is_residual, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
def xavier_uniform_param_init_fn_(module: nn.Module, n_layers: int, d_model: Optional[int]=None, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, init_gain: float=0, verbose: int=0, **kwargs):
del kwargs
xavier_uniform_ = partial(torch.nn.init.xavier_uniform_, gain=init_gain)
if verbose > 1:
warnings.warn(f'Using torch.nn.init.xavier_uniform_ init fn with parameters: ' + f'gain={init_gain}')
generic_param_init_fn_(module=module, init_fn_=xavier_uniform_, d_model=d_model, n_layers=n_layers, init_div_is_residual=init_div_is_residual, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
def xavier_normal_param_init_fn_(module: nn.Module, n_layers: int, d_model: Optional[int]=None, init_div_is_residual: Union[int, float, str, bool]=True, emb_init_std: Optional[float]=None, emb_init_uniform_lim: Optional[Union[Tuple[float, float], float]]=None, init_gain: float=0, verbose: int=0, **kwargs):
xavier_normal_ = partial(torch.nn.init.xavier_normal_, gain=init_gain)
if verbose > 1:
warnings.warn(f'Using torch.nn.init.xavier_normal_ init fn with parameters: ' + f'gain={init_gain}')
generic_param_init_fn_(module=module, init_fn_=xavier_normal_, d_model=d_model, n_layers=n_layers, init_div_is_residual=init_div_is_residual, emb_init_std=emb_init_std, emb_init_uniform_lim=emb_init_uniform_lim, verbose=verbose)
MODEL_INIT_REGISTRY = {'default_': torch_default_param_init_fn_, 'baseline_': baseline_param_init_fn_, 'kaiming_uniform_': kaiming_uniform_param_init_fn_, 'kaiming_normal_': kaiming_normal_param_init_fn_, 'neox_init_': neox_param_init_fn_, 'small_init_': small_param_init_fn_, 'xavier_uniform_': xavier_uniform_param_init_fn_, 'xavier_normal_': xavier_normal_param_init_fn_} |