ColossalAI/examples/language/gpt/titans/model/embed.py

582 lines
24 KiB
Python

import torch
import torch.nn.init as init
from torch import Tensor
from torch import nn as nn
from torch.nn import functional as F
from torch.nn.parameter import Parameter
from colossalai.legacy.context import ParallelMode, seed
from colossalai.legacy.core import global_context as gpc
from colossalai.legacy.nn.layer.base_layer import ParallelLayer
from colossalai.legacy.nn.layer.parallel_1d._utils import gather_forward_split_backward, reduce_grad, reduce_input
from colossalai.legacy.nn.layer.parallel_1d.layers import Linear1D_Row
from colossalai.legacy.nn.layer.utils import divide
from colossalai.legacy.registry import LAYERS, LOSSES
from colossalai.utils import get_current_device
class VocabParallelEmbedding(torch.nn.Module):
"""Language model embeddings.
Arguments:
hidden_size: hidden size
vocab_size: vocabulary size
max_sequence_length: maximum size of sequence. This
is used for positional embedding
embedding_dropout_prob: dropout probability for embeddings
init_method: weight initialization method
num_tokentypes: size of the token-type embeddings. 0 value
will ignore this embedding
"""
def __init__(
self, hidden_size, vocab_size, max_sequence_length, embedding_dropout_prob, num_tokentypes=0, dtype=torch.float
):
super(VocabParallelEmbedding, self).__init__()
self.hidden_size = hidden_size
self.num_tokentypes = num_tokentypes
# Word embeddings (parallel).
self.word_embeddings = VocabParallelEmbedding1D(vocab_size, self.hidden_size, dtype=dtype)
self._word_embeddings_key = "word_embeddings"
# Position embedding (serial).
self.position_embeddings = torch.nn.Embedding(max_sequence_length, self.hidden_size, dtype=dtype)
self._position_embeddings_key = "position_embeddings"
# Initialize the position embeddings.
# self.init_method(self.position_embeddings.weight)
# Token type embedding.
# Add this as an optional field that can be added through
# method call so we can load a pretrain model without
# token types and add them as needed.
self._tokentype_embeddings_key = "tokentype_embeddings"
if self.num_tokentypes > 0:
self.tokentype_embeddings = torch.nn.Embedding(self.num_tokentypes, self.hidden_size, dtype=dtype)
# Initialize the token-type embeddings.
# self.init_method(self.tokentype_embeddings.weight)
else:
self.tokentype_embeddings = None
# Embeddings dropout
self.embedding_dropout = torch.nn.Dropout(embedding_dropout_prob)
def zero_parameters(self):
"""Zero out all parameters in embedding."""
self.word_embeddings.weight.data.fill_(0)
self.word_embeddings.weight.shared = True
self.position_embeddings.weight.data.fill_(0)
self.position_embeddings.weight.shared = True
if self.num_tokentypes > 0:
self.tokentype_embeddings.weight.data.fill_(0)
self.tokentype_embeddings.weight.shared = True
def add_tokentype_embeddings(self, num_tokentypes):
"""Add token-type embedding. This function is provided so we can add
token-type embeddings in case the pretrained model does not have it.
This allows us to load the model normally and then add this embedding.
"""
if self.tokentype_embeddings is not None:
raise Exception("tokentype embeddings is already initialized")
if torch.distributed.get_rank() == 0:
print("adding embedding for {} tokentypes".format(num_tokentypes), flush=True)
self.num_tokentypes = num_tokentypes
self.tokentype_embeddings = torch.nn.Embedding(num_tokentypes, self.hidden_size)
# Initialize the token-type embeddings.
# self.init_method(self.tokentype_embeddings.weight)
def forward(self, input_ids, position_ids=None, tokentype_ids=None):
# Embeddings.
if input_ids is not None:
input_shape = input_ids.size()
input_ids = input_ids.view(-1, input_shape[-1])
words_embeddings = self.word_embeddings(input_ids)
if position_ids is not None:
position_ids = position_ids.view(-1, input_shape[-1])
if position_ids is None:
position_ids = torch.arange(0, input_shape[-1] + 0, dtype=torch.long, device=get_current_device())
position_ids = position_ids.unsqueeze(0).view(-1, input_shape[-1])
position_embeddings = self.position_embeddings(position_ids)
embeddings = words_embeddings + position_embeddings
# Dropout.
with seed(ParallelMode.TENSOR):
embeddings = self.embedding_dropout(embeddings)
return embeddings
def state_dict_for_save_checkpoint(self, destination=None, prefix="", keep_vars=False):
"""For easy load."""
state_dict_ = {}
state_dict_[self._word_embeddings_key] = self.word_embeddings.state_dict(destination, prefix, keep_vars)
state_dict_[self._position_embeddings_key] = self.position_embeddings.state_dict(destination, prefix, keep_vars)
if self.num_tokentypes > 0:
state_dict_[self._tokentype_embeddings_key] = self.tokentype_embeddings.state_dict(
destination, prefix, keep_vars
)
return state_dict_
def load_state_dict(self, state_dict, strict=True):
"""Customized load."""
# Word embedding.
if self._word_embeddings_key in state_dict:
state_dict_ = state_dict[self._word_embeddings_key]
else:
# for backward compatibility.
state_dict_ = {}
for key in state_dict.keys():
if "word_embeddings" in key:
state_dict_[key.split("word_embeddings.")[1]] = state_dict[key]
self.word_embeddings.load_state_dict(state_dict_, strict=strict)
# Position embedding.
if self._position_embeddings_key in state_dict:
state_dict_ = state_dict[self._position_embeddings_key]
else:
# for backward compatibility.
state_dict_ = {}
for key in state_dict.keys():
if "position_embeddings" in key:
state_dict_[key.split("position_embeddings.")[1]] = state_dict[key]
self.position_embeddings.load_state_dict(state_dict_, strict=strict)
# Tokentype embedding.
if self.num_tokentypes > 0:
state_dict_ = {}
if self._tokentype_embeddings_key in state_dict:
state_dict_ = state_dict[self._tokentype_embeddings_key]
else:
# for backward compatibility.
for key in state_dict.keys():
if "tokentype_embeddings" in key:
state_dict_[key.split("tokentype_embeddings.")[1]] = state_dict[key]
if len(state_dict_.keys()) > 0:
self.tokentype_embeddings.load_state_dict(state_dict_, strict=strict)
else:
print(
"***WARNING*** expected tokentype embeddings in the " "checkpoint but could not find it", flush=True
)
class VocabParallelEmbedding1D(torch.nn.Module):
"""Embedding parallelized in the vocabulary dimension.
This is mainly adapted from torch.nn.Embedding and all the default
values are kept.
Arguments:
num_embeddings: vocabulary size.
embedding_dim: size of hidden state.
init_method: method to initialize weights.
"""
def __init__(self, num_embeddings, embedding_dim, dtype=None, init_method=None):
super(VocabParallelEmbedding1D, self).__init__()
# Keep the input dimensions.
self.num_embeddings = num_embeddings
self.embedding_dim = embedding_dim
# Set the details for compatibility.
self.padding_idx = None
self.max_norm = None
self.norm_type = 2.0
self.scale_grad_by_freq = False
self.sparse = False
self._weight = None
self.tensor_model_parallel_size = gpc.tensor_parallel_size
# Divide the weight matrix along the vocabulary dimension.
self.vocab_start_index, self.vocab_end_index = VocabUtility.vocab_range_from_global_vocab_size(
self.num_embeddings, gpc.get_local_rank(ParallelMode.PARALLEL_1D), self.tensor_model_parallel_size
)
self.num_embeddings_per_partition = self.vocab_end_index - self.vocab_start_index
# Allocate weights and initialize.
factory_kwargs = {"device": get_current_device(), "dtype": dtype}
self.weight = Parameter(torch.empty(self.num_embeddings_per_partition, self.embedding_dim, **factory_kwargs))
init.uniform_(self.weight, -1, 1)
def forward(self, input_):
if self.tensor_model_parallel_size > 1:
# Build the mask.
input_mask = (input_ < self.vocab_start_index) | (input_ >= self.vocab_end_index)
# Mask the input.
masked_input = input_.clone() - self.vocab_start_index
masked_input[input_mask] = 0
else:
masked_input = input_
# Get the embeddings.
output_parallel = F.embedding(
masked_input,
self.weight,
self.padding_idx,
self.max_norm,
self.norm_type,
self.scale_grad_by_freq,
self.sparse,
)
# Mask the output embedding.
if self.tensor_model_parallel_size > 1:
output_parallel[input_mask, :] = 0.0
# Reduce across all the model parallel GPUs.
output = output = reduce_input(output_parallel, ParallelMode.PARALLEL_1D)
return output
@LOSSES.register_module
class vocab_parallel_cross_entropy(nn.Module):
def __init__(self):
super().__init__()
def forward(self, vocab_parallel_logits, target):
"""Helper function for the cross entropy."""
vocab_parallel_logits = vocab_parallel_logits[..., :-1, :].contiguous()
target = target[..., 1:].contiguous()
return _VocabParallelCrossEntropy.apply(
vocab_parallel_logits.view(-1, vocab_parallel_logits.size(-1)), target.view(-1)
)
class _VocabParallelCrossEntropy(torch.autograd.Function):
@staticmethod
def forward(ctx, vocab_parallel_logits, target):
# Maximum value along vocab dimension across all GPUs.
logits_max = torch.max(vocab_parallel_logits, dim=-1)[0]
torch.distributed.all_reduce(
logits_max, op=torch.distributed.ReduceOp.MAX, group=gpc.get_group(ParallelMode.PARALLEL_1D)
)
# Subtract the maximum value.
vocab_parallel_logits.sub_(logits_max.unsqueeze(dim=-1))
# Get the partition's vocab indices
get_vocab_range = VocabUtility.vocab_range_from_per_partition_vocab_size
partition_vocab_size = vocab_parallel_logits.size()[-1]
rank = gpc.get_local_rank(ParallelMode.PARALLEL_1D)
world_size = gpc.tensor_parallel_size
vocab_start_index, vocab_end_index = get_vocab_range(partition_vocab_size, rank, world_size)
# Create a mask of valid vocab ids (1 means it needs to be masked).
target_mask = (target < vocab_start_index) | (target >= vocab_end_index)
masked_target = target.clone() - vocab_start_index
masked_target[target_mask] = 0
# Get predicted-logits = logits[target].
# For Simplicity, we convert logits to a 2-D tensor with size
# [*, partition-vocab-size] and target to a 1-D tensor of size [*].
logits_2d = vocab_parallel_logits.view(-1, partition_vocab_size)
masked_target_1d = masked_target.view(-1)
arange_1d = torch.arange(start=0, end=logits_2d.size()[0], device=logits_2d.device)
predicted_logits_1d = logits_2d[arange_1d, masked_target_1d]
predicted_logits_1d = predicted_logits_1d.clone().contiguous()
predicted_logits = predicted_logits_1d.view_as(target)
predicted_logits[target_mask] = 0.0
# All reduce is needed to get the chunks from other GPUs.
torch.distributed.all_reduce(
predicted_logits, op=torch.distributed.ReduceOp.SUM, group=gpc.get_group(ParallelMode.PARALLEL_1D)
)
# Sum of exponential of logits along vocab dimension across all GPUs.
exp_logits = vocab_parallel_logits
torch.exp(vocab_parallel_logits, out=exp_logits)
sum_exp_logits = exp_logits.sum(dim=-1)
torch.distributed.all_reduce(
sum_exp_logits, op=torch.distributed.ReduceOp.SUM, group=gpc.get_group(ParallelMode.PARALLEL_1D)
)
# Loss = log(sum(exp(logits))) - predicted-logit.
loss = torch.log(sum_exp_logits) - predicted_logits
loss = loss.mean()
# Store softmax, target-mask and masked-target for backward pass.
exp_logits.div_(sum_exp_logits.unsqueeze(dim=-1))
ctx.save_for_backward(exp_logits, target_mask, masked_target_1d)
return loss
@staticmethod
def backward(ctx, grad_output):
# Retrieve tensors from the forward path.
softmax, target_mask, masked_target_1d = ctx.saved_tensors
# All the inputs have softmax as their gradient.
grad_input = softmax
# For simplicity, work with the 2D gradient.
partition_vocab_size = softmax.size()[-1]
grad_2d = grad_input.view(-1, partition_vocab_size)
# Add the gradient from matching classes.
arange_1d = torch.arange(start=0, end=grad_2d.size()[0], device=grad_2d.device)
grad_2d[arange_1d, masked_target_1d] -= 1.0 - target_mask.view(-1).float()
# Finally elementwise multiplication with the output gradients.
grad_input.mul_(grad_output.unsqueeze(dim=-1))
return grad_input, None
class VocabUtility:
"""Split the vocabulary into `world_size` chunks amd return the
first and last index of the vocabulary belonging to the `rank`
partition: Note that indices in [fist, last)"""
@staticmethod
def vocab_range_from_per_partition_vocab_size(per_partition_vocab_size, rank, world_size):
index_f = rank * per_partition_vocab_size
index_l = index_f + per_partition_vocab_size
return index_f, index_l
@staticmethod
def vocab_range_from_global_vocab_size(global_vocab_size, rank, world_size):
per_partition_vocab_size = divide(global_vocab_size, world_size)
return VocabUtility.vocab_range_from_per_partition_vocab_size(per_partition_vocab_size, rank, world_size)
class VocabParallelGPTLMHead1D(ParallelLayer):
"""
Language model head that shares the same parameters with the embedding matrix.
"""
def __init__(self, embed=None, vocab_size=None, dtype=None, embed_dim=None):
super().__init__()
if embed is not None:
self.head = embed
else:
self.head = VocabParallelEmbedding1D(vocab_size, embed_dim, dtype=dtype)
def forward(self, x: Tensor) -> Tensor:
x = reduce_grad(x, ParallelMode.PARALLEL_1D)
x = F.linear(x, self.head.weight)
return x
###################################
class HiddenParallelEmbedding(torch.nn.Module):
"""Language model embeddings.
Arguments:
hidden_size: hidden size
vocab_size: vocabulary size
max_sequence_length: maximum size of sequence. This
is used for positional embedding
embedding_dropout_prob: dropout probability for embeddings
init_method: weight initialization method
num_tokentypes: size of the token-type embeddings. 0 value
will ignore this embedding
"""
def __init__(
self,
hidden_size,
vocab_size,
max_sequence_length,
embedding_dropout_prob,
dtype=torch.float,
padding_idx: int = 0,
num_tokentypes=0,
):
super(HiddenParallelEmbedding, self).__init__()
self.hidden_size = hidden_size
self.num_tokentypes = num_tokentypes
# Word embeddings (parallel).
self.word_embeddings = HiddenParallelEmbedding1D(vocab_size, hidden_size, dtype, padding_idx)
self._word_embeddings_key = "word_embeddings"
# Position embedding (serial).
self.position_embeddings = torch.nn.Embedding(max_sequence_length, self.hidden_size)
self._position_embeddings_key = "position_embeddings"
# Initialize the position embeddings.
# self.init_method(self.position_embeddings.weight)
# Token type embedding.
# Add this as an optional field that can be added through
# method call so we can load a pretrain model without
# token types and add them as needed.
self._tokentype_embeddings_key = "tokentype_embeddings"
if self.num_tokentypes > 0:
self.tokentype_embeddings = torch.nn.Embedding(self.num_tokentypes, self.hidden_size)
# Initialize the token-type embeddings.
# self.init_method(self.tokentype_embeddings.weight)
else:
self.tokentype_embeddings = None
# Embeddings dropout
self.embedding_dropout = torch.nn.Dropout(embedding_dropout_prob)
def zero_parameters(self):
"""Zero out all parameters in embedding."""
self.word_embeddings.weight.data.fill_(0)
self.word_embeddings.weight.shared = True
self.position_embeddings.weight.data.fill_(0)
self.position_embeddings.weight.shared = True
if self.num_tokentypes > 0:
self.tokentype_embeddings.weight.data.fill_(0)
self.tokentype_embeddings.weight.shared = True
def add_tokentype_embeddings(self, num_tokentypes):
"""Add token-type embedding. This function is provided so we can add
token-type embeddings in case the pretrained model does not have it.
This allows us to load the model normally and then add this embedding.
"""
if self.tokentype_embeddings is not None:
raise Exception("tokentype embeddings is already initialized")
if torch.distributed.get_rank() == 0:
print("adding embedding for {} tokentypes".format(num_tokentypes), flush=True)
self.num_tokentypes = num_tokentypes
self.tokentype_embeddings = torch.nn.Embedding(num_tokentypes, self.hidden_size)
# Initialize the token-type embeddings.
# self.init_method(self.tokentype_embeddings.weight)
def forward(self, input_ids, position_ids=None, tokentype_ids=None):
if input_ids is not None:
input_shape = input_ids.size()
input_ids = input_ids.view(-1, input_shape[-1])
words_embeddings = self.word_embeddings(input_ids)
if position_ids is not None:
position_ids = position_ids.view(-1, input_shape[-1])
if position_ids is None:
position_ids = torch.arange(0, input_shape[-1] + 0, dtype=torch.long, device=get_current_device())
position_ids = position_ids.unsqueeze(0).view(-1, input_shape[-1])
position_embeddings = self.position_embeddings(position_ids)
embeddings = words_embeddings + position_embeddings
# Dropout.
with seed(ParallelMode.TENSOR):
embeddings = self.embedding_dropout(embeddings)
return embeddings
def state_dict_for_save_checkpoint(self, destination=None, prefix="", keep_vars=False):
"""For easy load."""
state_dict_ = {}
state_dict_[self._word_embeddings_key] = self.word_embeddings.state_dict(destination, prefix, keep_vars)
state_dict_[self._position_embeddings_key] = self.position_embeddings.state_dict(destination, prefix, keep_vars)
if self.num_tokentypes > 0:
state_dict_[self._tokentype_embeddings_key] = self.tokentype_embeddings.state_dict(
destination, prefix, keep_vars
)
return state_dict_
def load_state_dict(self, state_dict, strict=True):
"""Customized load."""
# Word embedding.
if self._word_embeddings_key in state_dict:
state_dict_ = state_dict[self._word_embeddings_key]
else:
# for backward compatibility.
state_dict_ = {}
for key in state_dict.keys():
if "word_embeddings" in key:
state_dict_[key.split("word_embeddings.")[1]] = state_dict[key]
self.word_embeddings.load_state_dict(state_dict_, strict=strict)
# Position embedding.
if self._position_embeddings_key in state_dict:
state_dict_ = state_dict[self._position_embeddings_key]
else:
# for backward compatibility.
state_dict_ = {}
for key in state_dict.keys():
if "position_embeddings" in key:
state_dict_[key.split("position_embeddings.")[1]] = state_dict[key]
self.position_embeddings.load_state_dict(state_dict_, strict=strict)
# Tokentype embedding.
if self.num_tokentypes > 0:
state_dict_ = {}
if self._tokentype_embeddings_key in state_dict:
state_dict_ = state_dict[self._tokentype_embeddings_key]
else:
# for backward compatibility.
for key in state_dict.keys():
if "tokentype_embeddings" in key:
state_dict_[key.split("tokentype_embeddings.")[1]] = state_dict[key]
if len(state_dict_.keys()) > 0:
self.tokentype_embeddings.load_state_dict(state_dict_, strict=strict)
else:
print(
"***WARNING*** expected tokentype embeddings in the " "checkpoint but could not find it", flush=True
)
class HiddenParallelEmbedding1D(torch.nn.Module):
"""Embedding parallelized in the vocabulary dimension.
This is mainly adapted from torch.nn.Embedding and all the default
values are kept.
Arguments:
num_embeddings: vocabulary size.
embedding_dim: size of hidden state.
init_method: method to initialize weights.
"""
def __init__(self, num_embeddings, embedding_dim, dtype=torch.float, padding_idx: int = None, init_method=None):
super(HiddenParallelEmbedding1D, self).__init__()
# Keep the input dimensions.
self.num_embeddings = num_embeddings
self.embedding_dim = embedding_dim
embed_dim_per_partition = divide(embedding_dim, gpc.tensor_parallel_size)
# Set the details for compatibility.
self.padding_idx = padding_idx
self.max_norm = None
self.norm_type = 2.0
self.scale_grad_by_freq = False
self.sparse = False
self._weight = None
# Allocate weights and initialize.
factory_kwargs = {"device": get_current_device(), "dtype": dtype}
self.weight = Parameter(torch.empty(num_embeddings, embed_dim_per_partition, **factory_kwargs))
init.uniform_(self.weight, -1, 1)
def forward(self, input_):
# Get the embeddings.
output_parallel = F.embedding(
input_, self.weight, self.padding_idx, self.max_norm, self.norm_type, self.scale_grad_by_freq, self.sparse
)
# Reduce across all the model parallel GPUs.
output = gather_forward_split_backward(output_parallel, ParallelMode.PARALLEL_1D, dim=-1)
return output
@LAYERS.register_module
class HiddenParallelGPTLMHead1D(ParallelLayer):
"""
Language model head that shares the same parameters with the embedding matrix.
"""
def __init__(
self,
embed=None,
embed_dim=None,
vocab_size=None,
dtype=None,
):
super().__init__()
if embed is not None:
self.head = embed
self.synced_embed = True
else:
# self.embedding = HiddenParallelEmbedding1D(vocab_size, hidden_size, dtype, padding_idx)
# (hidden_size/q, vocab_size)
self.synced_embed = False
self.head = Linear1D_Row(
in_features=embed_dim, out_features=vocab_size, bias=False, dtype=dtype, parallel_input=False
)
def forward(self, x: Tensor) -> Tensor:
if self.synced_embed:
x = F.linear(x, self.head.weight)
else:
x = self.head(x)
return x