titulm-1b-bn-v1 / modeling_mpt.py
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"""A simple, flexible implementation of a GPT model.
Inspired by https://github.com/karpathy/minGPT/blob/master/mingpt/model.py
"""
import math
import warnings
from typing import Any, Dict, List, Mapping, MutableMapping, Optional, Tuple, Union
import torch
import torch.nn as nn
import torch.nn.functional as F
from .attention import is_flash_v2_installed
if is_flash_v2_installed():
try:
from flash_attn.layers.rotary import RotaryEmbedding as DAILRotaryEmbedding
except Exception as e:
raise e
from transformers import PreTrainedModel, PreTrainedTokenizerBase
from transformers.modeling_outputs import BaseModelOutputWithPast, CausalLMOutputWithPast
from transformers.models.llama.modeling_llama import LlamaDynamicNTKScalingRotaryEmbedding as HFDynamicNTKScalingRotaryEmbedding
from transformers.models.llama.modeling_llama import LlamaLinearScalingRotaryEmbedding as HFLinearScalingRotaryEmbedding
from transformers.models.llama.modeling_llama import LlamaRotaryEmbedding as HFRotaryEmbedding
from .attention import ATTN_CLASS_REGISTRY, attn_bias_shape, build_attn_bias
from .blocks import MPTBlock
from .custom_embedding import SharedEmbedding
from .fc import FC_CLASS_REGISTRY as FC_CLASS_REGISTRY
from .ffn import FFN_CLASS_REGISTRY as FFN_CLASS_REGISTRY
from .ffn import MPTMLP as MPTMLP
from .ffn import build_ffn as build_ffn
from .norm import NORM_CLASS_REGISTRY
from .configuration_mpt import MPTConfig
from .adapt_tokenizer import AutoTokenizerForMOD, adapt_tokenizer_for_denoising
from .hf_prefixlm_converter import add_bidirectional_mask_if_missing, convert_hf_causal_lm_to_prefix_lm
from .meta_init_context import init_empty_weights
from .param_init_fns import generic_param_init_fn_, MODEL_INIT_REGISTRY
try:
from .flash_attn_triton import flash_attn_func as flash_attn_func
except:
pass
import logging
log = logging.getLogger(__name__)
def gen_rotary_embedding(rope_head_dim: int, rope_impl: str, rope_theta: int, rope_dail_config: dict, rope_hf_config: dict, max_seq_len: int):
if rope_impl == 'dail':
return DAILRotaryEmbedding(dim=rope_head_dim, base=rope_theta, interleaved=False, scale_base=rope_dail_config['xpos_scale_base'] if rope_dail_config['type'] == 'xpos' else None, pos_idx_in_fp32=rope_dail_config['pos_idx_in_fp32'], device='cpu')
elif rope_impl == 'hf':
if rope_hf_config['type'] == 'no_scaling':
return HFRotaryEmbedding(rope_head_dim, max_position_embeddings=max_seq_len, base=rope_theta, device='cpu')
elif rope_hf_config['type'] == 'linear':
return HFLinearScalingRotaryEmbedding(rope_head_dim, max_position_embeddings=max_seq_len, base=rope_theta, scaling_factor=rope_hf_config['factor'], device='cpu')
elif rope_hf_config['type'] == 'dynamic':
return HFDynamicNTKScalingRotaryEmbedding(rope_head_dim, max_position_embeddings=max_seq_len, base=rope_theta, scaling_factor=rope_hf_config['factor'], device='cpu')
raise ValueError('rope_impl needs to be either dail or hf')
class MPTPreTrainedModel(PreTrainedModel):
config_class = MPTConfig
base_model_prefix = 'model'
_no_split_modules = ['MPTBlock']
class MPTModel(MPTPreTrainedModel):
def __init__(self, config: MPTConfig):
config._validate_config()
super().__init__(config)
self.attn_impl = config.attn_config['attn_impl']
self.prefix_lm = config.attn_config['prefix_lm']
self.attn_uses_sequence_id = config.attn_config['attn_uses_sequence_id']
self.alibi = config.attn_config['alibi']
self.alibi_bias_max = config.attn_config['alibi_bias_max']
self.learned_pos_emb = config.learned_pos_emb
if config.init_device == 'mixed':
if dist.get_local_rank() == 0:
config.init_device = 'cpu'
else:
config.init_device = 'meta'
if config.norm_type.lower() not in NORM_CLASS_REGISTRY.keys():
norm_options = ' | '.join(NORM_CLASS_REGISTRY.keys())
raise NotImplementedError(f'Requested norm type ({config.norm_type}) is not implemented within this repo (Options: {norm_options}).')
norm_class = NORM_CLASS_REGISTRY[config.norm_type.lower()]
self.embedding_fraction = config.embedding_fraction
self.wte = SharedEmbedding(config.vocab_size, config.d_model, device=config.init_device)
if self.learned_pos_emb:
self.wpe = torch.nn.Embedding(config.max_seq_len, config.d_model, device=config.init_device)
self.emb_drop = nn.Dropout(config.emb_pdrop)
self.blocks = nn.ModuleList([MPTBlock(device=config.init_device, **config.to_dict()) for _ in range(config.n_layers)])
self.norm_f = norm_class(config.d_model, device=config.init_device)
self.rope = config.attn_config['rope']
self.rope_impl = None
if self.rope:
self.rope_impl = config.attn_config['rope_impl']
self.rotary_embedding = gen_rotary_embedding(rope_head_dim=config.d_model // config.n_heads, rope_impl=self.rope_impl, rope_theta=config.attn_config['rope_theta'], rope_dail_config=config.attn_config['rope_dail_config'], rope_hf_config=config.attn_config['rope_hf_config'], max_seq_len=self.config.max_seq_len)
if config.init_device != 'meta':
log.info(f'We recommend using config.init_device="meta" with Composer + FSDP for faster initialization.')
self.apply(self.param_init_fn)
self.is_causal = not self.prefix_lm
self._attn_bias_initialized = False
self.attn_bias = None
self.attn_bias_shape = attn_bias_shape(self.attn_impl, config.n_heads, config.max_seq_len, self.alibi, prefix_lm=self.prefix_lm, causal=self.is_causal, use_sequence_id=self.attn_uses_sequence_id)
if config.no_bias:
for module in self.modules():
if hasattr(module, 'bias') and isinstance(module.bias, nn.Parameter):
log.info(f'Removing bias ({module.bias}) from {module}.')
module.register_parameter('bias', None)
if hasattr(module, 'use_bias'):
log.info(f'Setting use_bias=False for {module}.')
module.use_bias = False
log.debug(self)
log.debug(f"Using {self.config.init_config['name']} initialization.")
def get_input_embeddings(self) -> Union[SharedEmbedding, nn.Embedding]:
return self.wte
def set_input_embeddings(self, value: Union[SharedEmbedding, nn.Embedding]) -> None:
self.wte = value
@torch.no_grad()
def _attn_bias(self, device: torch.device, dtype: torch.dtype, attention_mask: Optional[torch.ByteTensor]=None, prefix_mask: Optional[torch.ByteTensor]=None, sequence_id: Optional[torch.LongTensor]=None) -> Tuple[Optional[torch.Tensor], Optional[torch.ByteTensor]]:
if not self._attn_bias_initialized:
if self.attn_bias_shape:
self.attn_bias = torch.zeros(self.attn_bias_shape, device=device, dtype=dtype)
self.attn_bias = build_attn_bias(self.attn_impl, self.attn_bias, self.config.n_heads, self.config.max_seq_len, causal=self.is_causal, alibi=self.alibi, alibi_bias_max=self.alibi_bias_max)
self._attn_bias_initialized = True
if self.attn_impl == 'flash':
return (self.attn_bias, attention_mask)
if self.attn_bias is not None:
self.attn_bias = self.attn_bias.to(dtype=dtype, device=device)
attn_bias = self.attn_bias
if self.prefix_lm:
assert isinstance(attn_bias, torch.Tensor)
assert isinstance(prefix_mask, torch.Tensor)
attn_bias = self._apply_prefix_mask(attn_bias, prefix_mask)
if self.attn_uses_sequence_id and sequence_id is not None:
assert isinstance(attn_bias, torch.Tensor)
attn_bias = self._apply_sequence_id(attn_bias, sequence_id)
if attention_mask is not None:
s_k = attention_mask.shape[-1]
if attn_bias is None:
attn_bias = torch.zeros((1, 1, 1, s_k), device=device, dtype=dtype)
else:
_s_k = max(0, attn_bias.size(-1) - s_k)
attn_bias = attn_bias[:, :, :, _s_k:]
if prefix_mask is not None and attention_mask.shape != prefix_mask.shape:
raise ValueError(f'attention_mask shape={attention_mask.shape} ' + f'and prefix_mask shape={prefix_mask.shape} are not equal.')
min_val = torch.finfo(attn_bias.dtype).min
attn_bias = attn_bias.masked_fill(~attention_mask.view(-1, 1, 1, s_k), min_val)
return (attn_bias, None)
def _apply_prefix_mask(self, attn_bias: torch.Tensor, prefix_mask: torch.Tensor) -> torch.Tensor:
(s_k, s_q) = attn_bias.shape[-2:]
if s_k != self.config.max_seq_len or s_q != self.config.max_seq_len:
raise ValueError('attn_bias does not match the expected shape. ' + f'The last two dimensions should both be {self.config.max_length} ' + f'but are {s_k} and {s_q}.')
seq_len = prefix_mask.shape[-1]
if seq_len > self.config.max_seq_len:
raise ValueError(f'prefix_mask sequence length cannot exceed max_seq_len={self.config.max_seq_len}')
attn_bias = attn_bias[..., :seq_len, :seq_len]
causal = torch.tril(torch.ones((seq_len, seq_len), dtype=torch.bool, device=prefix_mask.device)).view(1, 1, seq_len, seq_len)
prefix = prefix_mask.view(-1, 1, 1, seq_len)
cannot_attend = ~torch.logical_or(causal, prefix.bool())
min_val = torch.finfo(attn_bias.dtype).min
attn_bias = attn_bias.masked_fill(cannot_attend, min_val)
return attn_bias
def _apply_sequence_id(self, attn_bias: torch.Tensor, sequence_id: torch.LongTensor) -> torch.Tensor:
seq_len = sequence_id.shape[-1]
if seq_len > self.config.max_seq_len:
raise ValueError(f'sequence_id sequence length cannot exceed max_seq_len={self.config.max_seq_len}')
attn_bias = attn_bias[..., :seq_len, :seq_len]
cannot_attend = torch.logical_not(torch.eq(sequence_id.view(-1, seq_len, 1), sequence_id.view(-1, 1, seq_len))).unsqueeze(1)
min_val = torch.finfo(attn_bias.dtype).min
attn_bias = attn_bias.masked_fill(cannot_attend, min_val)
return attn_bias
def forward(self, input_ids: torch.LongTensor, past_key_values: Optional[List[Tuple[torch.FloatTensor]]]=None, attention_mask: Optional[torch.ByteTensor]=None, prefix_mask: Optional[torch.ByteTensor]=None, sequence_id: Optional[torch.LongTensor]=None, return_dict: Optional[bool]=None, output_attentions: Optional[bool]=None, output_hidden_states: Optional[bool]=None, use_cache: Optional[bool]=None, inputs_embeds: Optional[torch.Tensor]=None) -> BaseModelOutputWithPast:
return_dict = return_dict if return_dict is not None else self.config.return_dict
use_cache = use_cache if use_cache is not None else self.config.use_cache
if attention_mask is not None:
attention_mask = attention_mask.bool()
if prefix_mask is not None:
prefix_mask = prefix_mask.bool()
if not return_dict:
raise NotImplementedError('return_dict False is not implemented yet for MPT')
if output_attentions:
if self.attn_impl != 'torch':
raise NotImplementedError('output_attentions is not implemented for MPT when using attn_impl `flash` or `triton`.')
if self.training and attention_mask is not None and (attention_mask[:, 0].sum() != attention_mask.shape[0]):
raise NotImplementedError('MPT does not support training with left padding.')
if self.prefix_lm and prefix_mask is None:
raise ValueError('prefix_mask is a required argument when MPT is configured with prefix_lm=True.')
if inputs_embeds is not None:
raise NotImplementedError('inputs_embeds is not implemented for MPT.')
if self.training:
if self.attn_uses_sequence_id and sequence_id is None:
raise ValueError('sequence_id is a required argument when MPT is configured with attn_uses_sequence_id=True ' + 'and the model is in train mode.')
elif self.attn_uses_sequence_id is False and sequence_id is not None:
warnings.warn('MPT received non-None input for `sequence_id` but is configured with attn_uses_sequence_id=False. ' + 'This input will be ignored. If you want the model to use `sequence_id`, set attn_uses_sequence_id to True.')
S = input_ids.size(1)
assert S <= self.config.max_seq_len, f'Cannot forward input with seq_len={S}, this model only supports seq_len<={self.config.max_seq_len}'
rotary_emb_w_meta_info = None
x = self.wte(input_ids)
if self.learned_pos_emb or self.rope:
past_position = 0
if past_key_values is not None:
if len(past_key_values) != self.config.n_layers:
raise ValueError(f'past_key_values must provide a past_key_value for each attention ' + f'layer in the network (len(past_key_values)={len(past_key_values)!r}; self.config.n_layers={self.config.n_layers!r}).')
past_position = past_key_values[0][0].size(1)
if self.attn_impl == 'torch':
past_position = past_key_values[0][0].size(3)
if self.learned_pos_emb and S + past_position > self.config.max_seq_len:
raise ValueError(f'Cannot forward input with past sequence length {past_position} and current sequence length ' + f'{S + 1}, this model only supports total sequence length <= {self.config.max_seq_len}.')
if self.learned_pos_emb or (self.rope and self.rope_impl == 'hf'):
pos = torch.arange(past_position, S + past_position, dtype=torch.long, device=input_ids.device).unsqueeze(0)
if attention_mask is not None:
pos = torch.clamp(pos - torch.cumsum((~attention_mask).to(torch.int32), dim=1)[:, past_position:], min=0)
if self.learned_pos_emb:
x = x + self.wpe(pos)
elif self.rope and self.rope_impl == 'hf':
rotary_emb_w_meta_info = {'impl': self.rope_impl, 'rotary_emb': self.rotary_embedding, 'offset_info': pos, 'seq_len': S + past_position}
elif self.rope and self.rope_impl == 'dail':
rotary_emb_w_meta_info = {'impl': self.rope_impl, 'rotary_emb': self.rotary_embedding, 'offset_info': past_position, 'seq_len': S + past_position}
if self.embedding_fraction == 1:
x = self.emb_drop(x)
else:
x_shrunk = x * self.embedding_fraction + x.detach() * (1 - self.embedding_fraction)
assert isinstance(self.emb_drop, nn.Module)
x = self.emb_drop(x_shrunk)
(attn_bias, attention_mask) = self._attn_bias(device=x.device, dtype=torch.float32, attention_mask=attention_mask, prefix_mask=prefix_mask, sequence_id=sequence_id)
presents = () if use_cache else None
if use_cache and past_key_values is None:
past_key_values = [() for _ in range(self.config.n_layers)]
all_hidden_states = () if output_hidden_states else None
all_self_attns = () if output_attentions else None
for (b_idx, block) in enumerate(self.blocks):
if output_hidden_states:
assert all_hidden_states is not None
all_hidden_states = all_hidden_states + (x,)
past_key_value = past_key_values[b_idx] if past_key_values is not None else None
(x, attn_weights, present) = block(x, past_key_value=past_key_value, attn_bias=attn_bias, rotary_emb_w_meta_info=rotary_emb_w_meta_info, attention_mask=attention_mask, is_causal=self.is_causal, output_attentions=bool(output_attentions))
if presents is not None:
presents += (present,)
if output_attentions:
assert all_self_attns is not None
all_self_attns = all_self_attns + (attn_weights,)
x = self.norm_f(x)
if output_hidden_states:
assert all_hidden_states is not None
all_hidden_states = all_hidden_states + (x,)
return BaseModelOutputWithPast(last_hidden_state=x, past_key_values=presents, hidden_states=all_hidden_states, attentions=all_self_attns)
def param_init_fn(self, module: nn.Module) -> None:
init_fn_name = self.config.init_config['name']
MODEL_INIT_REGISTRY[init_fn_name](module=module, n_layers=self.config.n_layers, d_model=self.config.d_model, **self.config.init_config)
def fsdp_wrap_fn(self, module: nn.Module) -> bool:
return isinstance(module, MPTBlock)
def activation_checkpointing_fn(self, module: nn.Module) -> bool:
return isinstance(module, MPTBlock)
class MPTForCausalLM(MPTPreTrainedModel):
def __init__(self, config: MPTConfig):
super().__init__(config)
log.info(f'Instantiating an MPTForCausalLM model from {__file__}')
self.transformer: MPTModel = MPTModel(config)
self.lm_head = None
if not config.tie_word_embeddings:
self.lm_head = nn.Linear(config.d_model, config.vocab_size, bias=False, device=config.init_device)
self.lm_head._fsdp_wrap = True
for child in self.transformer.children():
if isinstance(child, torch.nn.ModuleList):
continue
if isinstance(child, torch.nn.Module):
child._fsdp_wrap = True
self.logit_scale = None
if config.logit_scale is not None:
logit_scale = config.logit_scale
if isinstance(logit_scale, str):
if logit_scale == 'inv_sqrt_d_model':
logit_scale = 1 / math.sqrt(config.d_model)
else:
raise ValueError(f"logit_scale={logit_scale!r} is not recognized as an option; use numeric value or 'inv_sqrt_d_model'.")
self.logit_scale = logit_scale
def get_input_embeddings(self) -> Union[SharedEmbedding, nn.Embedding]:
return self.transformer.get_input_embeddings()
def set_input_embeddings(self, value: Union[SharedEmbedding, nn.Embedding]) -> None:
self.transformer.set_input_embeddings(value)
def get_output_embeddings(self) -> Union[SharedEmbedding, nn.Embedding, nn.Linear]:
if self.lm_head is not None:
return self.lm_head
return self.transformer.get_input_embeddings()
def set_output_embeddings(self, new_embeddings: Union[SharedEmbedding, nn.Embedding, nn.Linear]) -> None:
if self.lm_head is not None:
self.lm_head = new_embeddings
else:
if not isinstance(new_embeddings, (SharedEmbedding, nn.Embedding)):
raise ValueError('new_embeddings must be an instance of SharedEmbedding ' + f'or nn.Embedding, but got {type(new_embeddings)}.')
warnings.warn('Using `set_output_embeddings` to set the embedding layer of ' + 'MPTForCausalLM with tied weights. Given weights are tied, ' + 'using `set_input_embeddings` is recommended over using ' + '`set_output_embeddings`.')
self.transformer.set_input_embeddings(new_embeddings)
def tie_weights(self) -> None:
self.lm_head = None
def set_decoder(self, decoder: MPTModel) -> None:
self.transformer = decoder
def get_decoder(self) -> MPTModel:
return self.transformer
def forward(self, input_ids: torch.LongTensor, past_key_values: Optional[List[Tuple[torch.FloatTensor]]]=None, attention_mask: Optional[torch.ByteTensor]=None, prefix_mask: Optional[torch.ByteTensor]=None, sequence_id: Optional[torch.LongTensor]=None, labels: Optional[torch.LongTensor]=None, return_dict: Optional[bool]=None, output_attentions: Optional[bool]=None, output_hidden_states: Optional[bool]=None, use_cache: Optional[bool]=None, inputs_embeds: Optional[torch.FloatTensor]=None) -> CausalLMOutputWithPast:
return_dict = return_dict if return_dict is not None else self.config.return_dict
use_cache = use_cache if use_cache is not None else self.config.use_cache
if inputs_embeds is not None:
raise NotImplementedError('inputs_embeds has to be None (for hf/peft support).')
outputs = self.transformer(input_ids=input_ids, past_key_values=past_key_values, attention_mask=attention_mask, prefix_mask=prefix_mask, sequence_id=sequence_id, return_dict=return_dict, output_attentions=output_attentions, output_hidden_states=output_hidden_states, use_cache=use_cache)
if self.lm_head is not None:
logits = self.lm_head(outputs.last_hidden_state)
else:
out = outputs.last_hidden_state
out = out.to(self.transformer.wte.weight.device)
logits = self.transformer.wte(out, True)
if self.logit_scale is not None:
if self.logit_scale == 0:
warnings.warn(f'Multiplying logits by self.logit_scale={self.logit_scale!r}. This will produce uniform (uninformative) outputs.')
logits *= self.logit_scale
loss = None
if labels is not None:
_labels = torch.roll(labels, shifts=-1)
_labels[:, -1] = -100
loss = F.cross_entropy(logits.view(-1, logits.size(-1)), _labels.to(logits.device).view(-1))
return CausalLMOutputWithPast(loss=loss, logits=logits, past_key_values=outputs.past_key_values, hidden_states=outputs.hidden_states, attentions=outputs.attentions)
def param_init_fn(self, module: nn.Module) -> None:
init_fn_name = self.config.init_config['name']
MODEL_INIT_REGISTRY[init_fn_name](module=module, n_layers=self.config.n_layers, d_model=self.config.d_model, **self.config.init_config)
def fsdp_wrap_fn(self, module: nn.Module) -> bool:
return isinstance(module, MPTBlock)
def activation_checkpointing_fn(self, module: nn.Module) -> bool:
act_ckpt_list = getattr(self.config, 'activation_checkpointing_target', None) or ['MPTBlock']
if 'MPTBlock' in act_ckpt_list or 'mptblock' in act_ckpt_list:
if len(act_ckpt_list) > 1:
log.info('Activation checkpointing MPTBlock only (ignoring other sub-block modules specified in activation_checkpointing_target).')
return isinstance(module, MPTBlock)
mod_types = ()
for mod_name in act_ckpt_list:
if mod_name.lower() == 'mptblock':
mod_types += (MPTBlock,)
elif mod_name in ATTN_CLASS_REGISTRY:
mod_types += (ATTN_CLASS_REGISTRY[mod_name],)
elif mod_name in FFN_CLASS_REGISTRY:
mod_types += (FFN_CLASS_REGISTRY[mod_name],)
elif mod_name in NORM_CLASS_REGISTRY:
mod_types += (NORM_CLASS_REGISTRY[mod_name],)
else:
msg = ', '.join(list(ATTN_CLASS_REGISTRY.keys()) + list(FFN_CLASS_REGISTRY.keys()) + list(NORM_CLASS_REGISTRY.keys()) + ['MPTBlock'])
raise ValueError(f'{mod_name} (specified in activation_checkpointing_target) is not a recognized option out of available options {msg}.')
return isinstance(module, mod_types)
def prepare_inputs_for_generation(self, input_ids: torch.Tensor, past_key_values: Optional[List[Tuple[torch.Tensor, torch.Tensor]]]=None, inputs_embeds: Optional[torch.Tensor]=None, **kwargs: Any) -> Dict[str, Any]:
if inputs_embeds is not None:
raise NotImplementedError('inputs_embeds is not implemented for MPT yet')
attention_mask = kwargs['attention_mask'].bool()
if attention_mask[:, -1].sum() != attention_mask.shape[0]:
raise NotImplementedError('MPT does not support generation with right padding.')
if self.transformer.attn_uses_sequence_id and self.training:
sequence_id = torch.zeros_like(input_ids[:1])
else:
sequence_id = None
if past_key_values is not None:
input_ids = input_ids[:, -1].unsqueeze(-1)
if self.transformer.prefix_lm:
prefix_mask = torch.ones_like(attention_mask)
if kwargs.get('use_cache') == False:
raise NotImplementedError('MPT with prefix_lm=True does not support use_cache=False.')
else:
prefix_mask = None
return {'input_ids': input_ids, 'attention_mask': attention_mask, 'prefix_mask': prefix_mask, 'sequence_id': sequence_id, 'past_key_values': past_key_values, 'use_cache': kwargs.get('use_cache', True)}
@staticmethod
def _reorder_cache(past_key_values: List[Tuple[torch.Tensor, torch.Tensor]], beam_idx: torch.LongTensor) -> List[Tuple[torch.Tensor, ...]]:
"""Used by HuggingFace generate when using beam search with kv-caching.
See https://github.com/huggingface/transformers/blob/3ec7a47664ebe40c40f4b722f6bb1cd30c3821ec/src/transformers/models/gpt2/modeling_gpt2.py#L1122-L1133
for an example in transformers.
"""
reordered_past = []
for layer_past in past_key_values:
reordered_past += [tuple((past_state.index_select(0, beam_idx) for past_state in layer_past))]
return reordered_past