long_llama_3b_instruct / modeling_longllama.py
Szymon Tworkowski
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# coding=utf-8
# Copyright 2023 EleutherAI and the HuggingFace Inc. team. All rights reserved.
#
# This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX
# and OPT implementations in this library. It has been modified from its
# original forms to accommodate minor architectural differences compared
# to GPT-NeoX and OPT used by the Meta AI team that trained the model.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
""" PyTorch LongLLaMA model."""
from dataclasses import dataclass
import math
from typing import List, Optional, Tuple, Union
import torch
import torch.utils.checkpoint
from torch import nn
from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss
from transformers.activations import ACT2FN
from transformers.modeling_outputs import (
BaseModelOutputWithPast,
CausalLMOutputWithPast,
SequenceClassifierOutputWithPast,
)
from transformers.modeling_utils import PreTrainedModel
from transformers.utils import (
add_start_docstrings,
add_start_docstrings_to_model_forward,
logging,
replace_return_docstrings,
)
from .configuration_longllama import LongLlamaConfig
from .longllama_utils import mem_apply_update, LongLlamaMemCache, LongLlamaMemConfig
logger = logging.get_logger(__name__)
_CONFIG_FOR_DOC = "LongLlamaConfig"
@dataclass
class LongLlamaModelOutputWithPast(BaseModelOutputWithPast):
"""
Based on BaseModelOutputWithPast
Args:
last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`):
past_key_values (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`):
hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`):
mem_caches (`tuple(LongLlamaMemCache))`, *optional*, returned for layers with memory cache enabled):
For the layers without memory None is returned
"""
mem_caches: Optional[LongLlamaMemCache] = None
# Copied from transformers.models.bart.modeling_bart._make_causal_mask
def _make_causal_mask(
input_ids_shape: torch.Size, dtype: torch.dtype, device: torch.device, past_key_values_length: int = 0
):
"""
Make causal mask used for bi-directional self-attention.
"""
bsz, tgt_len = input_ids_shape
mask = torch.full((tgt_len, tgt_len), torch.tensor(torch.finfo(dtype).min, device=device), device=device)
mask_cond = torch.arange(mask.size(-1), device=device)
mask.masked_fill_(mask_cond < (mask_cond + 1).view(mask.size(-1), 1), 0)
mask = mask.to(dtype)
if past_key_values_length > 0:
mask = torch.cat([torch.zeros(tgt_len, past_key_values_length, dtype=dtype, device=device), mask], dim=-1)
return mask[None, None, :, :].expand(bsz, 1, tgt_len, tgt_len + past_key_values_length)
# Copied from transformers.models.bart.modeling_bart._expand_mask
def _expand_mask(mask: torch.Tensor, dtype: torch.dtype, tgt_len: Optional[int] = None):
"""
Expands attention_mask from `[bsz, seq_len]` to `[bsz, 1, tgt_seq_len, src_seq_len]`.
"""
bsz, src_len = mask.size()
tgt_len = tgt_len if tgt_len is not None else src_len
expanded_mask = mask[:, None, None, :].expand(bsz, 1, tgt_len, src_len).to(dtype)
inverted_mask = 1.0 - expanded_mask
return inverted_mask.masked_fill(inverted_mask.to(torch.bool), torch.finfo(dtype).min)
# Copied from transformers.models.llama.modeling_llama.LlamaRMSNorm with Llama->LongLlama
class LongLlamaRMSNorm(nn.Module):
def __init__(self, hidden_size, eps=1e-6):
"""
LongLlamaRMSNorm is equivalent to T5LayerNorm
"""
super().__init__()
self.weight = nn.Parameter(torch.ones(hidden_size))
self.variance_epsilon = eps
def forward(self, hidden_states):
input_dtype = hidden_states.dtype
variance = hidden_states.to(torch.float32).pow(2).mean(-1, keepdim=True)
hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
return (self.weight * hidden_states).to(input_dtype)
# Copied from transformers.models.llama.modeling_llama.LlamaRotaryEmbedding with Llama->LongLlama
class LongLlamaRotaryEmbedding(torch.nn.Module):
def __init__(self, dim, max_position_embeddings=2048, base=10000, device=None):
super().__init__()
inv_freq = 1.0 / (base ** (torch.arange(0, dim, 2).float().to(device) / dim))
self.register_buffer("inv_freq", inv_freq)
# Build here to make `torch.jit.trace` work.
self.max_seq_len_cached = max_position_embeddings
t = torch.arange(self.max_seq_len_cached, device=self.inv_freq.device, dtype=self.inv_freq.dtype)
freqs = torch.einsum("i,j->ij", t, self.inv_freq)
# Different from paper, but it uses a different permutation in order to obtain the same calculation
emb = torch.cat((freqs, freqs), dim=-1)
dtype = torch.get_default_dtype()
self.register_buffer("cos_cached", emb.cos()[None, None, :, :].to(dtype), persistent=False)
self.register_buffer("sin_cached", emb.sin()[None, None, :, :].to(dtype), persistent=False)
def forward(self, x, seq_len=None):
# x: [bs, num_attention_heads, seq_len, head_size]
# This `if` block is unlikely to be run after we build sin/cos in `__init__`. Keep the logic here just in case.
if seq_len > self.max_seq_len_cached:
self.max_seq_len_cached = seq_len
t = torch.arange(self.max_seq_len_cached, device=x.device, dtype=self.inv_freq.dtype)
freqs = torch.einsum("i,j->ij", t, self.inv_freq)
# Different from paper, but it uses a different permutation in order to obtain the same calculation
emb = torch.cat((freqs, freqs), dim=-1).to(x.device)
self.register_buffer("cos_cached", emb.cos()[None, None, :, :].to(x.dtype), persistent=False)
self.register_buffer("sin_cached", emb.sin()[None, None, :, :].to(x.dtype), persistent=False)
return (
self.cos_cached[:, :, :seq_len, ...].to(dtype=x.dtype),
self.sin_cached[:, :, :seq_len, ...].to(dtype=x.dtype),
)
def rotate_half(x):
"""Rotates half the hidden dims of the input."""
x1 = x[..., : x.shape[-1] // 2]
x2 = x[..., x.shape[-1] // 2 :]
return torch.cat((-x2, x1), dim=-1)
# Based on transformers.models.llama.modeling_llama.apply_rotary_pos_emb
def rotate_one(x, cos, sin, position_ids):
if len(position_ids.shape) != 2 or x.shape[0] != position_ids.shape[0] or x.shape[-2] != position_ids.shape[1]:
raise ValueError(f"Position ids shoud have shape [bsz, seq_len] got {position_ids.shape}")
# The first two dimensions of cos and sin are always 1, so we can `squeeze` them.
cos = cos.squeeze(1).squeeze(0) # [seq_len, dim]
sin = sin.squeeze(1).squeeze(0) # [seq_len, dim]
cos = cos[position_ids].unsqueeze(1) # [bs, 1, seq_len, dim]
sin = sin[position_ids].unsqueeze(1) # [bs, 1, seq_len, dim]
x_embed = (x * cos) + (rotate_half(x) * sin)
return x_embed
def rotate_as_if_first(x, rotary_emb):
# x: [bs, num_attention_heads, seq_len, head_size]
# apply rotary as if all elements were first in the sequence
cos, sin = rotary_emb(x, x.shape[-2])
return rotate_one(x, cos, sin, torch.zeros(x.shape[0], x.shape[-2], dtype=torch.long, device=cos.device))
# Copied from transformers.models.llama.modeling_llama.LlamaMLP with Llama->LongLlama
class LongLlamaMLP(nn.Module):
def __init__(
self,
hidden_size: int,
intermediate_size: int,
hidden_act: str,
):
super().__init__()
self.gate_proj = nn.Linear(hidden_size, intermediate_size, bias=False)
self.down_proj = nn.Linear(intermediate_size, hidden_size, bias=False)
self.up_proj = nn.Linear(hidden_size, intermediate_size, bias=False)
self.act_fn = ACT2FN[hidden_act]
def forward(self, x):
return self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x))
# Modified transformers.models.llama.modeling_llama.LlamaAttention
class LongLlamaAttention(nn.Module):
"""Multi-headed attention from 'Attention Is All You Need' paper with FoT modifications"""
def __init__(self, config: LongLlamaConfig, mem_config: Optional[LongLlamaMemConfig] = None):
super().__init__()
self.config = config
self.hidden_size = config.hidden_size
self.num_heads = config.num_attention_heads
self.head_dim = self.hidden_size // self.num_heads
self.max_position_embeddings = config.max_position_embeddings
self.max_cache = self.max_position_embeddings
if (self.head_dim * self.num_heads) != self.hidden_size:
raise ValueError(
f"hidden_size must be divisible by num_heads (got `hidden_size`: {self.hidden_size}"
f" and `num_heads`: {self.num_heads})."
)
self.q_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=False)
self.k_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=False)
self.v_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=False)
self.o_proj = nn.Linear(self.num_heads * self.head_dim, self.hidden_size, bias=False)
self.rotary_emb = LongLlamaRotaryEmbedding(self.head_dim, max_position_embeddings=self.max_position_embeddings)
self.mem_config = mem_config
def _shape(self, tensor: torch.Tensor, seq_len: int, bsz: int):
return tensor.view(bsz, seq_len, self.num_heads, self.head_dim).transpose(1, 2).contiguous()
def forward(
self,
hidden_states: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_value: Optional[Tuple[torch.Tensor]] = None,
output_attentions: bool = False,
use_cache: bool = False,
mem_cache: Optional[LongLlamaMemCache] = None,
) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]:
if attention_mask is None:
tgt_seq_len = hidden_states.shape[-2]
if past_key_value is not None:
src_seq_len = past_key_value[0].shape[-2] + tgt_seq_len
else:
src_seq_len = tgt_seq_len
attention_mask = torch.zeros(
hidden_states.shape[0],
1,
tgt_seq_len,
src_seq_len,
device=hidden_states.device,
dtype=hidden_states.dtype,
)
bsz, q_len, _ = hidden_states.size()
query_states = self.q_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
key_states = self.k_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
value_states = self.v_proj(hidden_states).view(bsz, q_len, self.num_heads, self.head_dim).transpose(1, 2)
position_ids = position_ids[:, None, :, None]
if position_ids.shape != (key_states.shape[0], 1, key_states.shape[-2], 1):
raise ValueError("position_ids should match batch and seq_len of the input")
mem_no_local_cache = self.mem_config is not None and past_key_value is None and (not use_cache)
mem_and_local_cache = self.mem_config is not None and use_cache
# positonal embeddings can be disabled for memory layers
use_positionals = self.mem_config is None or self.mem_config.positionals
if mem_no_local_cache:
# the whole context window will be moved to memory cache after the attention
if use_positionals:
# positionally embedd memory content as first token in the sequence
rfst_key_states = rotate_as_if_first(key_states, self.rotary_emb)
else:
rfst_key_states = key_states
# attention_mask [bsz, 1, tgt_seq_len, src_seq_len]
# we base the mask on the last token in the context window
mem_update = LongLlamaMemCache(
keys=rfst_key_states.to(self.mem_config.cache_dtype),
values=value_states.to(self.mem_config.cache_dtype),
masks=attention_mask[..., -1, :, None],
)
if past_key_value is not None:
past_local_cache_size = past_key_value[0].shape[-2]
key_states = torch.cat([past_key_value[0], key_states], dim=-2)
value_states = torch.cat([past_key_value[1], value_states], dim=-2)
# FoT additionally stores position_ids to support long inputs
position_ids = torch.cat([past_key_value[2], position_ids], dim=-2)
if attention_mask.shape[-1] != key_states.shape[-2] and attention_mask.shape[-2] != query_states.shape[-2]:
raise ValueError("attention_mask should be provided for all key_states in local context")
# local cache is maintained so that it is <= self.max_cache
# remaining elements are either dropped or go to memory cache
if key_states.shape[-2] > self.max_cache:
num_elems_to_drop = past_local_cache_size
if mem_and_local_cache:
drop_keys = key_states[:, :, :num_elems_to_drop, :]
drop_values = value_states[:, :, :num_elems_to_drop, :]
# as memory mask use the masking of the last key in context
# attention_mask [bsz, 1, tgt_seq_len, src_seq_len]
drop_masks = attention_mask[..., -1, :, None]
drop_masks = drop_masks[:, :, :num_elems_to_drop, :]
if use_positionals:
rfst_drop_keys = rotate_as_if_first(drop_keys, self.rotary_emb)
else:
rfst_drop_keys = drop_keys
mem_update = LongLlamaMemCache(
keys=rfst_drop_keys.to(self.mem_config.cache_dtype),
values=drop_values.to(self.mem_config.cache_dtype),
masks=drop_masks,
)
if mem_cache is None:
mem_cache = mem_update
else:
mem_cache = mem_apply_update(
prev_mem_cache=mem_cache, new_mem_content=mem_update, mem_config=self.mem_config
)
key_states = key_states[:, :, num_elems_to_drop:, :]
value_states = value_states[:, :, num_elems_to_drop:, :]
position_ids = position_ids[:, :, num_elems_to_drop:, :]
attention_mask = attention_mask[..., num_elems_to_drop:]
# FoT additionally stores position_ids to support long inputs
past_key_value = (key_states, value_states, position_ids) if use_cache else None
kv_seq_len = key_states.shape[-2]
if use_positionals:
cos, sin = self.rotary_emb(value_states, seq_len=kv_seq_len)
rel_pos_ids = position_ids - torch.min(position_ids, dim=-2, keepdim=True)[0]
rel_pos_ids = rel_pos_ids.squeeze(3).squeeze(1)
query_states = rotate_one(query_states, cos, sin, rel_pos_ids[:, -query_states.shape[-2] :])
key_states = rotate_one(key_states, cos, sin, rel_pos_ids)
if self.mem_config is not None and self.mem_config.attention_grouping is not None:
attn_grouping_h, attn_grouping_q = self.mem_config.attention_grouping
if attn_grouping_h <= 0 or attn_grouping_q <= 0:
raise ValueError("Attention grouping should be positive")
else:
attn_grouping_h, attn_grouping_q = self.num_heads, q_len
attn_output_h = []
for beg_h in range(0, self.num_heads, attn_grouping_h):
end_h = min(beg_h + attn_grouping_h, self.num_heads)
attn_output_q = []
for beg_q in range(0, q_len, attn_grouping_q):
end_q = min(beg_q + attn_grouping_q, q_len)
if self.config.torch_attention:
if mem_cache is not None:
attn_keys = torch.concat(
[key_states[:, beg_h:end_h], mem_cache.keys[:, beg_h:end_h].to(key_states.dtype)], dim=-2
)
attn_values = torch.concat(
[value_states[:, beg_h:end_h], mem_cache.values[:, beg_h:end_h].to(value_states.dtype)],
dim=-2,
)
mem_mask = mem_cache.masks.squeeze(-1).unsqueeze(-2)
assert len(mem_mask.shape) == 4
assert mem_mask.shape[2] == 1
assert mem_mask.shape[3] == mem_cache.keys.shape[-2]
mem_mask = torch.broadcast_to(
mem_mask, (mem_mask.shape[0], mem_mask.shape[1], end_q - beg_q, mem_mask.shape[3])
)
attn_mask = torch.concat([attention_mask[:, :, beg_q:end_q], mem_mask], dim=-1)
assert attn_mask.shape[-1] == attn_keys.shape[-2]
else:
attn_keys = key_states[:, beg_h:end_h]
attn_values = value_states[:, beg_h:end_h]
attn_mask = attention_mask[:, :, beg_q:end_q]
attn_queries = query_states[:, beg_h:end_h, beg_q:end_q]
attn_output = torch.nn.functional.scaled_dot_product_attention(
query=attn_queries, key=attn_keys, value=attn_values, attn_mask=attn_mask
)
attn_output_q.append(attn_output)
else:
attn_weights = torch.matmul(
query_states[:, beg_h:end_h, beg_q:end_q], key_states[:, beg_h:end_h].transpose(2, 3)
) / math.sqrt(self.head_dim)
if attn_weights.size() != (bsz, end_h - beg_h, end_q - beg_q, kv_seq_len):
raise ValueError(
f"Attention weights should be of size {(bsz, end_h - beg_h, end_q - beg_q, kv_seq_len)}, but is"
f" {attn_weights.size()}"
)
if attention_mask.size() != (bsz, 1, q_len, kv_seq_len):
raise ValueError(
f"Attention mask should be of size {(bsz, 1, q_len, kv_seq_len)}, but is {attention_mask.size()}"
)
attn_weights = attn_weights + attention_mask[:, :, beg_q:end_q]
min_value = (
torch.finfo(attn_weights.dtype).min
if -1000000.0 < torch.finfo(attn_weights.dtype).min
else -1000000.0
)
attn_weights = torch.max(
attn_weights, torch.tensor(min_value, device=attn_weights.device, dtype=attn_weights.dtype)
)
if mem_cache is not None:
mem_mask = mem_cache.masks.squeeze(-1).unsqueeze(-2)
mem_attn_weights = torch.matmul(
query_states[:, beg_h:end_h, beg_q:end_q],
mem_cache.keys[:, beg_h:end_h].transpose(2, 3).to(key_states.dtype),
) / math.sqrt(self.head_dim)
assert mem_mask.shape[2] == 1
mem_attn_weights = mem_attn_weights + mem_mask
min_value = (
torch.finfo(mem_attn_weights.dtype).min
if -1000000.0 < torch.finfo(mem_attn_weights.dtype).min
else -1000000.0
)
mem_attn_weights = torch.max(
mem_attn_weights,
torch.tensor(min_value, device=mem_attn_weights.device, dtype=mem_attn_weights.dtype),
)
attn_weights = torch.concat([attn_weights, mem_attn_weights], dim=-1)
combined_value_states = torch.concat(
[value_states[:, beg_h:end_h], mem_cache.values[:, beg_h:end_h].to(value_states.dtype)],
dim=-2,
)
else:
combined_value_states = value_states[:, beg_h:end_h]
# upcast attention to fp32
attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(
query_states.dtype
)
attn_output = torch.matmul(attn_weights, combined_value_states)
assert attn_output.shape[-2] == end_q - beg_q
attn_output_q.append(attn_output)
attn_output_h.append(torch.concat(attn_output_q, dim=-2))
attn_output = torch.concat(attn_output_h, dim=-3)
if attn_output.size() != (bsz, self.num_heads, q_len, self.head_dim):
raise ValueError(
f"`attn_output` should be of size {(bsz, self.num_heads, q_len, self.head_dim)}, but is"
f" {attn_output.size()}"
)
attn_output = attn_output.transpose(1, 2)
attn_output = attn_output.reshape(bsz, q_len, self.hidden_size)
attn_output = self.o_proj(attn_output)
if not output_attentions:
attn_weights = None
if mem_no_local_cache:
if mem_cache is not None:
mem_cache = mem_apply_update(
prev_mem_cache=mem_cache, new_mem_content=mem_update, mem_config=self.mem_config
)
else:
mem_cache = mem_update
return attn_output, attn_weights, past_key_value, mem_cache
# Modified transformers.models.llama.modeling_llama.LlamaDecoderLayer
class LongLlamaDecoderLayer(nn.Module):
def __init__(self, config: LongLlamaConfig, mem_config: Optional[LongLlamaMemConfig] = None):
super().__init__()
self.hidden_size = config.hidden_size
self.self_attn = LongLlamaAttention(config=config, mem_config=mem_config)
self.mlp = LongLlamaMLP(
hidden_size=self.hidden_size,
intermediate_size=config.intermediate_size,
hidden_act=config.hidden_act,
)
self.input_layernorm = LongLlamaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.post_attention_layernorm = LongLlamaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
def forward(
self,
hidden_states: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_value: Optional[Tuple[torch.Tensor]] = None,
output_attentions: Optional[bool] = False,
use_cache: Optional[bool] = False,
mem_cache: Optional[LongLlamaMemCache] = None,
) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]:
"""
Args:
hidden_states (`torch.FloatTensor`): input to the layer of shape `(batch, seq_len, embed_dim)`
attention_mask (`torch.FloatTensor`, *optional*): attention mask of size
`(batch, 1, tgt_len, src_len)` where padding elements are indicated by very large negative values.
output_attentions (`bool`, *optional*):
Whether or not to return the attentions tensors of all attention layers. See `attentions` under
returned tensors for more detail.
use_cache (`bool`, *optional*):
If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding
(see `past_key_values`).
past_key_value (`Tuple(torch.FloatTensor)`, *optional*): cached past key and value projection states
along with information about positions
mem_cache (`LongLlamaMemCache`, *optional*): memory cache for specific layers
"""
residual = hidden_states
hidden_states = self.input_layernorm(hidden_states)
# Self Attention
hidden_states, self_attn_weights, present_key_value, mem_cache = self.self_attn(
hidden_states=hidden_states,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_value=past_key_value,
output_attentions=output_attentions,
use_cache=use_cache,
mem_cache=mem_cache,
)
hidden_states = residual + hidden_states
# Fully Connected
residual = hidden_states
hidden_states = self.post_attention_layernorm(hidden_states)
hidden_states = self.mlp(hidden_states)
hidden_states = residual + hidden_states
outputs = (hidden_states,)
if output_attentions:
outputs += (self_attn_weights,)
if use_cache:
outputs += (present_key_value,)
return outputs + (mem_cache,)
LONGLLAMA_START_DOCSTRING = r"""
This model inherits from [`PreTrainedModel`]. Check the superclass documentation for the generic methods the
library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads
etc.)
This model is also a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) subclass.
Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage
and behavior.
Parameters:
config ([`LongLlamaConfig`]):
Model configuration class with all the parameters of the model. Initializing with a config file does not
load the weights associated with the model, only the configuration. Check out the
[`~PreTrainedModel.from_pretrained`] method to load the model weights.
"""
LONGLLAMA_MEML_DOCSTRING = r"""
mem_layers ([`int`], *optional*):
Indices of layers to be augmented with memory, if None then parameters from config will be used
mem_dtype (`str`, *optional*):
Keys and values will be casted to this type for storage.
"""
@add_start_docstrings(
"The bare LongLLaMA Model outputting raw hidden-states without any specific head on top.",
LONGLLAMA_START_DOCSTRING,
)
# Copied from transformers.models.llama.modeling_llama.LlamaPreTrainedModel with Llama->LongLlama
class LongLlamaPreTrainedModel(PreTrainedModel):
config_class = LongLlamaConfig
base_model_prefix = "model"
supports_gradient_checkpointing = True
_no_split_modules = ["LongLlamaDecoderLayer"]
_skip_keys_device_placement = "past_key_values"
_keys_to_ignore_on_load_unexpected = [r"decoder\.version"]
def _init_weights(self, module):
std = self.config.initializer_range
if isinstance(module, nn.Linear):
module.weight.data.normal_(mean=0.0, std=std)
if module.bias is not None:
module.bias.data.zero_()
elif isinstance(module, nn.Embedding):
module.weight.data.normal_(mean=0.0, std=std)
if module.padding_idx is not None:
module.weight.data[module.padding_idx].zero_()
def _set_gradient_checkpointing(self, module, value=False):
if isinstance(module, LongLlamaModel):
module.gradient_checkpointing = value
LONGLLAMA_COMMON_INPUTS_DOCSTRING = r"""
Args:
input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you provide
it.
Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
[`PreTrainedTokenizer.__call__`] for details.
[What are input IDs?](../glossary#input-ids)
attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*):
Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:
- 1 for tokens that are **not masked**,
- 0 for tokens that are **masked**.
[What are attention masks?](../glossary#attention-mask)
Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and
[`PreTrainedTokenizer.__call__`] for details.
If `past_key_values` is used, optionally only the last `decoder_input_ids` have to be input (see
`past_key_values`).
If you want to change padding behavior, you should read [`modeling_opt._prepare_decoder_attention_mask`]
and modify to your needs. See diagram 1 in [the paper](https://arxiv.org/abs/1910.13461) for more
information on the default strategy.
- 1 indicates the head is **not masked**,
- 0 indicates the head is **masked**.
position_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
Indices of positions of each input sequence tokens in the position embeddings.
[What are position IDs?](../glossary#position-ids)
past_key_values (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`
or memory cache is enabled):
Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of shape
`(batch_size, num_heads, sequence_length, embed_size_per_head)`) and 1 additional tensor of shape
`(batch_size, 1, sequence_length, 1)`. For memory enriched layers it also contains content of memory cache.
It is padded with empty tensors so when returned it alwyas has 6 elements.
Contains pre-computed hidden-states (key and values in the self-attention blocks)
that can be used (see `past_key_values` input) to speed up sequential decoding.
If `past_key_values` are used, the user can optionally input only the last `decoder_input_ids` (those that
don't have their past key value states given to this model) of shape `(batch_size, 1)` instead of all
`decoder_input_ids` of shape `(batch_size, sequence_length)`.
inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*):
Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This
is useful if you want more control over how to convert `input_ids` indices into associated vectors than the
model's internal embedding lookup matrix.
use_cache (`bool`, *optional*):
If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see
`past_key_values`).
output_attentions (`bool`, *optional*):
Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned
tensors for more detail. This is NOT supported in LongLlamaForCausalLM and LongLlamaForSequenceClassification
due to the specific input processing.
output_hidden_states (`bool`, *optional*):
Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for
more detail.
return_dict (`bool`, *optional*):
Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
"""
LONGLLAMA_MODEL_INPUTS_DOCSTRING = r"""
mem_caches (`tuple(LongLlamaMemCache)`, *optional*)
Memory caches for specified layers, None for others
"""
LONGLLAMA_ADD_INPUTS_DOCSTRING = r"""
last_context_length (`int`, *optional*)
Useful for generation, specifies number of tokens that won't be loaded to memory and
will be left for generation cache
"""
def _prepare_pos_ids(past_key_values, batch_size, input_length, device):
if past_key_values is not None:
# take previous max pos_id + 1
if past_key_values[0][2].shape[0] != batch_size:
raise ValueError(
f"first dimension of past_key_values should match batch size: {batch_size}"
f"but got {past_key_values[0][2].shape[0]}"
)
next_pos = torch.max(past_key_values[0][2].view(batch_size, -1), dim=-1)[0] + 1
next_pos = next_pos.view(batch_size, 1)
else:
next_pos = torch.zeros(batch_size, 1, device=device, dtype=torch.long)
position_ids = torch.arange(0, input_length, dtype=torch.long, device=device).view(1, input_length)
position_ids = position_ids + next_pos
return position_ids
@add_start_docstrings(
"The bare LongLLaMA Model outputting raw hidden-states without any specific head on top.",
LONGLLAMA_START_DOCSTRING,
LONGLLAMA_MEML_DOCSTRING,
)
# Modified transformers.models.llama.modeling_llama.LlamaModel
class LongLlamaModel(LongLlamaPreTrainedModel):
"""
Transformer decoder consisting of *config.num_hidden_layers* layers. Each layer is a [`LongLlamaDecoderLayer`]
Args:
config: LlamaConfig
"""
def __init__(self, config: LongLlamaConfig):
super().__init__(config)
self.mem_layers = config.mem_layers
self.mem_config = LongLlamaMemConfig(
positionals=config.mem_positionals,
cache_dtype=getattr(torch, config.mem_dtype),
attention_grouping=config.mem_attention_grouping,
)
self.padding_idx = config.pad_token_id
self.vocab_size = config.vocab_size
self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx)
for mem_layer_id in self.mem_layers:
if mem_layer_id < 0 or mem_layer_id >= config.num_hidden_layers:
raise ValueError(
f"Memory layer ids should be between 0 and {config.num_hidden_layers}, got {mem_layer_id}"
)
layers = []
for layer_id in range(config.num_hidden_layers):
if layer_id in self.mem_layers:
layer = LongLlamaDecoderLayer(config, mem_config=self.mem_config)
else:
layer = LongLlamaDecoderLayer(config, mem_config=None)
layers.append(layer)
self.layers = nn.ModuleList(layers)
self.norm = LongLlamaRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.gradient_checkpointing = False
# Initialize weights and apply final processing
self.post_init()
def get_input_embeddings(self):
return self.embed_tokens
def set_input_embeddings(self, value):
self.embed_tokens = value
# Copied from transformers.models.bart.modeling_bart.BartDecoder._prepare_decoder_attention_mask
def _prepare_decoder_attention_mask(self, attention_mask, input_shape, inputs_embeds, past_key_values_length):
# create causal mask
# [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len]
combined_attention_mask = None
if input_shape[-1] > 1:
combined_attention_mask = _make_causal_mask(
input_shape,
inputs_embeds.dtype,
device=inputs_embeds.device,
past_key_values_length=past_key_values_length,
)
if attention_mask is not None:
# [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len]
expanded_attn_mask = _expand_mask(attention_mask, inputs_embeds.dtype, tgt_len=input_shape[-1]).to(
inputs_embeds.device
)
combined_attention_mask = (
expanded_attn_mask if combined_attention_mask is None else expanded_attn_mask + combined_attention_mask
)
return combined_attention_mask
@add_start_docstrings_to_model_forward(LONGLLAMA_COMMON_INPUTS_DOCSTRING, LONGLLAMA_MODEL_INPUTS_DOCSTRING)
def forward(
self,
input_ids: torch.LongTensor = None,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_values: Optional[List[torch.FloatTensor]] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
mem_caches: Optional[Tuple[Optional[LongLlamaMemCache]]] = None,
) -> Union[Tuple, LongLlamaModelOutputWithPast]:
output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
output_hidden_states = (
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
)
use_cache = use_cache if use_cache is not None else self.config.use_cache
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
# retrieve input_ids and inputs_embeds
if input_ids is not None and inputs_embeds is not None:
raise ValueError("You cannot specify both decoder_input_ids and decoder_inputs_embeds at the same time")
elif input_ids is not None:
batch_size, seq_length = input_ids.shape
elif inputs_embeds is not None:
batch_size, seq_length, _ = inputs_embeds.shape
else:
raise ValueError("You have to specify either decoder_input_ids or decoder_inputs_embeds")
seq_length_with_past = seq_length
past_key_values_length = 0
if past_key_values is not None:
past_key_values_length = past_key_values[0][0].shape[-2]
seq_length_with_past = seq_length_with_past + past_key_values_length
if position_ids is None:
device = input_ids.device if input_ids is not None else inputs_embeds.device
position_ids = _prepare_pos_ids(past_key_values, batch_size, seq_length, device)
else:
position_ids = position_ids.view(-1, seq_length).long()
if inputs_embeds is None:
inputs_embeds = self.embed_tokens(input_ids)
# embed positions
if attention_mask is None:
attention_mask = torch.ones(
(batch_size, seq_length_with_past), dtype=torch.bool, device=inputs_embeds.device
)
attention_mask = self._prepare_decoder_attention_mask(
attention_mask, (batch_size, seq_length), inputs_embeds, past_key_values_length
)
hidden_states = inputs_embeds
if self.gradient_checkpointing and self.training:
if use_cache:
logger.warning_once(
"`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`..."
)
use_cache = False
# decoder layers
all_hidden_states = () if output_hidden_states else None
all_self_attns = () if output_attentions else None
next_decoder_cache = ()
next_mem_caches = ()
for idx, decoder_layer in enumerate(self.layers):
if output_hidden_states:
all_hidden_states += (hidden_states,)
past_key_value = past_key_values[idx] if past_key_values is not None else None
mem_cache = mem_caches[idx] if mem_caches else None
if mem_cache is not None and idx not in self.mem_layers:
raise ValueError("Memory cache provided for a non-memory leayer")
if (
self.gradient_checkpointing
and self.training
and mem_cache is None
and idx % self.config.gradient_checkpoint_every_ith == 0
):
def create_custom_forward(module):
def custom_forward(*inputs):
# None for past_key_value
return module(*inputs, output_attentions, None, mem_cache=None)
return custom_forward
layer_outputs = torch.utils.checkpoint.checkpoint(
create_custom_forward(decoder_layer),
hidden_states,
attention_mask,
position_ids,
None,
)
else:
layer_outputs = decoder_layer(
hidden_states,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_value=past_key_value,
output_attentions=output_attentions,
use_cache=use_cache,
mem_cache=mem_cache,
)
new_mem_cache = layer_outputs[-1]
layer_outputs = layer_outputs[:-1]
next_mem_caches += (new_mem_cache,)
hidden_states = layer_outputs[0]
if use_cache:
next_decoder_cache += (layer_outputs[2 if output_attentions else 1],)
else:
next_decoder_cache += (None,)
if output_attentions:
all_self_attns += (layer_outputs[1],)
hidden_states = self.norm(hidden_states)
# add hidden states from the last decoder layer
if output_hidden_states:
all_hidden_states += (hidden_states,)
next_cache = next_decoder_cache if use_cache else None
mem_cache_returned = False
for mem_cache in next_mem_caches:
if mem_cache is not None:
mem_cache_returned = True
next_mem_caches = next_mem_caches if mem_cache_returned else None
if not return_dict:
return tuple(
v
for v in [hidden_states, next_cache, all_hidden_states, all_self_attns, next_mem_caches]
if v is not None
)
return LongLlamaModelOutputWithPast(
last_hidden_state=hidden_states,
past_key_values=next_cache,
hidden_states=all_hidden_states,
attentions=all_self_attns,
mem_caches=next_mem_caches,
)
def _handle_output_of_past_key_values(outputs):
# merges local caches and memory caches into one single tuple of past_key_values
# in order to support generation
batch_size = outputs.last_hidden_state.shape[0]
if outputs.past_key_values is None and outputs.mem_caches is None:
return None
if outputs.past_key_values is None:
out_past_key_values = (None,) * len(outputs.mem_caches)
else:
out_past_key_values = outputs.past_key_values
if outputs.mem_caches is None:
out_mem_caches = (None,) * len(outputs.past_key_values)
else:
out_mem_caches = outputs.mem_caches
device = outputs.last_hidden_state.device
past_key_values = ()
for local_cache, mem_cache in zip(out_past_key_values, out_mem_caches):
layer = ()
if local_cache is not None:
assert len(local_cache) == 3
layer += local_cache
else:
layer += (torch.empty(batch_size, 0, 0, 0, device=device),) * 3
if mem_cache is not None:
layer += (mem_cache.keys, mem_cache.values, mem_cache.masks)
else:
layer += (torch.empty(batch_size, 0, 0, 0, device=device),) * 3
assert len(layer) == 6
past_key_values += (layer,)
return past_key_values
def _split_past_key_values(past_key_values):
# splits past_key_values to local cache and memory cache
local_cache_preset = False
mem_caches_present = False
if past_key_values is not None:
local_caches = ()
mem_caches = ()
for layer in past_key_values:
if len(layer) != 6:
raise ValueError(
"Expected elements of past_key_values to contain 6 elements."
"First 3 describing local cache and last 3 describing memory cache."
f"Instead got {len(layer)} elements"
)
else:
lk, lv, li, memk, memv, memm = layer
if lk.shape[-2] != 0:
local_cache_preset = True
local_caches += ((lk, lv, li),)
else:
local_caches += (None,)
if memk.shape[-2] != 0:
mem_caches_present = True
mem_caches += (LongLlamaMemCache(keys=memk, values=memv, masks=memm),)
else:
mem_caches += (None,)
local_caches = local_caches if local_cache_preset else None
mem_caches = mem_caches if mem_caches_present else None
return local_caches, mem_caches
def _handle_long_input(
model,
input_ids,
attention_mask,
position_ids,
past_key_values,
inputs_embeds,
use_cache,
output_attentions,
output_hidden_states,
return_dict,
context_window_length,
last_context_length,
):
if output_attentions:
logger.warning(
f"Outputing attentions is not supported in LongLlamaForCausalLM and LongLlamaForSequenceClassification. "
f"Attention of the last window will be returned"
)
past_key_values, mem_caches = _split_past_key_values(past_key_values)
if past_key_values is not None and use_cache is False:
raise ValueError("past_key_values it not None should imply use_cache == True")
if past_key_values is not None:
initial_past_key_values_length = past_key_values[0][0].shape[-2]
else:
initial_past_key_values_length = 0
if input_ids is not None:
batch_size, input_length = input_ids.shape
else:
batch_size, input_length, _ = inputs_embeds.shape
if position_ids is None:
device = input_ids.device if input_ids is not None else inputs_embeds.device
position_ids = _prepare_pos_ids(past_key_values, batch_size, input_length, device)
if position_ids.shape != (batch_size, input_length):
raise ValueError(f"Shape of position_ids [{position_ids}] should match [{batch_size, input_length}]")
if attention_mask is not None:
attention_mask = attention_mask[..., -(initial_past_key_values_length + input_length) :]
if attention_mask is not None and (
attention_mask.shape != (batch_size, initial_past_key_values_length + input_length)
):
raise ValueError(
"Attention mask should be provided for both the local cache and the input",
f"Expected shape {(batch_size, initial_past_key_values_length + input_length)},"
f"got {attention_mask.shape}.",
)
# First we load prefix to memory cache
mem_input_length = max(input_length - last_context_length, 0)
outputs_list = []
attn_offset = initial_past_key_values_length
if mem_input_length > 0:
for i in range(0, mem_input_length, context_window_length):
beg, end = i, min(mem_input_length, i + context_window_length)
if attention_mask is not None:
if past_key_values is not None:
local_cache_size = past_key_values[0][0].shape[-2]
else:
local_cache_size = 0
attn_length = attention_mask.shape[-1]
attn_beg = beg + attn_offset - local_cache_size
attn_end = end + attn_offset
assert attn_end <= attn_length
assert attn_beg >= 0 and attn_end > attn_beg
# decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn, mem_caches)
outputs = model(
input_ids=input_ids[..., beg:end] if input_ids is not None else None,
attention_mask=attention_mask[..., attn_beg:attn_end] if attention_mask is not None else None,
position_ids=position_ids[..., beg:end],
past_key_values=past_key_values,
inputs_embeds=inputs_embeds[..., beg:end, :] if inputs_embeds is not None else None,
use_cache=False if past_key_values is None else use_cache,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=True,
mem_caches=mem_caches,
)
if i > 0:
if mem_caches is not None and past_key_values is None:
for mc_layer in mem_caches:
if mc_layer is not None:
del mc_layer.keys
del mc_layer.values
del mc_layer.masks
mem_caches = outputs.mem_caches
outputs.mem_caches = None
past_key_values = outputs.past_key_values
outputs.past_key_values = None
outputs_list.append(outputs)
remaining_input_length = input_length - mem_input_length
beg = mem_input_length
attn_length = remaining_input_length
if past_key_values is not None:
attn_length += past_key_values[0][0].shape[-2]
attention_mask = attention_mask[..., -attn_length:] if attention_mask is not None else None
outputs = model(
input_ids=input_ids[..., beg:] if input_ids is not None else None,
attention_mask=attention_mask,
position_ids=position_ids[..., beg:],
past_key_values=past_key_values,
inputs_embeds=inputs_embeds[..., beg:, :] if inputs_embeds is not None else None,
use_cache=use_cache,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=True,
mem_caches=mem_caches,
)
outputs_list.append(outputs)
past_key_values = _handle_output_of_past_key_values(outputs_list[-1])
if output_hidden_states:
hidden_states = ()
for hd in zip(*[x.hidden_states for x in outputs_list]):
hidden_states += (torch.cat(hd, dim=-2),)
else:
hidden_states = None
outputs = BaseModelOutputWithPast(
last_hidden_state=torch.concat([x.last_hidden_state for x in outputs_list], dim=-2),
past_key_values=past_key_values,
hidden_states=hidden_states,
attentions=outputs_list[-1].attentions,
)
if not return_dict:
outputs = tuple(
v
for v in [outputs.last_hidden_state, outputs.past_key_values, outputs.hidden_states, outputs.attentions]
if v is not None
)
return outputs
# Modified transformers.models.llama.modeling_llama.LlamaForCausalLM
class LongLlamaForCausalLM(LongLlamaPreTrainedModel):
_tied_weights_keys = ["lm_head.weight"]
def __init__(self, config):
super().__init__(config)
self.context_window_length = config.max_position_embeddings
self.model = LongLlamaModel(config)
self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
# Initialize weights and apply final processing
self.post_init()
def get_input_embeddings(self):
return self.model.embed_tokens
def set_input_embeddings(self, value):
self.model.embed_tokens = value
def get_output_embeddings(self):
return self.lm_head
def set_output_embeddings(self, new_embeddings):
self.lm_head = new_embeddings
def set_decoder(self, decoder):
self.model = decoder
def get_decoder(self):
return self.model
def _has_generation_cache(self, past_key_values):
if past_key_values is not None:
assert len(past_key_values[0]) == 6
return past_key_values[0][0].shape[-2] != 0
return False
@add_start_docstrings_to_model_forward(LONGLLAMA_COMMON_INPUTS_DOCSTRING, LONGLLAMA_ADD_INPUTS_DOCSTRING)
@replace_return_docstrings(output_type=CausalLMOutputWithPast, config_class=_CONFIG_FOR_DOC)
def forward(
self,
input_ids: torch.LongTensor = None,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_values: Optional[List[torch.FloatTensor]] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
labels: Optional[torch.LongTensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
last_context_length: Optional[int] = None,
) -> Union[Tuple, CausalLMOutputWithPast]:
r"""
Args:
labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
(masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
Returns:
Example:
```python
>>> from transformers import AutoTokenizer, LlamaForCausalLM
>>> model = LlamaForCausalLM.from_pretrained(PATH_TO_CONVERTED_WEIGHTS)
>>> tokenizer = AutoTokenizer.from_pretrained(PATH_TO_CONVERTED_TOKENIZER)
>>> prompt = "Hey, are you conscious? Can you talk to me?"
>>> inputs = tokenizer(prompt, return_tensors="pt")
>>> # Generate
>>> generate_ids = model.generate(inputs.input_ids, max_length=30)
>>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
"Hey, are you conscious? Can you talk to me?\nI'm not conscious, but I can talk to you."
```"""
last_context_length = (
last_context_length if last_context_length is not None else self.config.last_context_length
)
output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
output_hidden_states = (
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
)
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
outputs = _handle_long_input(
model=self.model,
input_ids=input_ids,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
use_cache=use_cache,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
context_window_length=self.context_window_length,
last_context_length=last_context_length,
)
hidden_states = outputs[0]
logits = self.lm_head(hidden_states)
loss = None
if labels is not None:
# Shift so that tokens < n predict n
shift_logits = logits[..., :-1, :].contiguous()
shift_labels = labels[..., 1:].contiguous()
# Flatten the tokens
loss_fct = CrossEntropyLoss()
shift_logits = shift_logits.view(-1, self.config.vocab_size)
shift_labels = shift_labels.view(-1)
# Enable model parallelism
shift_labels = shift_labels.to(shift_logits.device)
loss = loss_fct(shift_logits, shift_labels)
if not return_dict:
output = (logits,) + outputs[1:]
return (loss,) + output if loss is not None else output
return CausalLMOutputWithPast(
loss=loss,
logits=logits,
past_key_values=outputs.past_key_values,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
)
def prepare_inputs_for_generation(
self,
input_ids,
past_key_values=None,
attention_mask=None,
inputs_embeds=None,
last_context_length=None,
**kwargs,
):
if self._has_generation_cache(past_key_values):
input_ids = input_ids[:, -1:]
position_ids = kwargs.get("position_ids", None)
if attention_mask is not None and position_ids is None:
# create position_ids on the fly for batch generation
position_ids = attention_mask.long().cumsum(-1) - 1
position_ids.masked_fill(position_ids < 0, 0)
if self._has_generation_cache(past_key_values):
position_ids = position_ids[:, -1].unsqueeze(-1)
# if `inputs_embeds` are passed, we only want to use them in the 1st generation step
if inputs_embeds is not None and past_key_values is None:
model_inputs = {"inputs_embeds": inputs_embeds}
else:
model_inputs = {"input_ids": input_ids}
model_inputs.update(
{
"position_ids": position_ids,
"past_key_values": past_key_values,
"use_cache": kwargs.get("use_cache"),
"attention_mask": attention_mask,
"last_context_length": last_context_length,
}
)
return model_inputs
@staticmethod
def _reorder_cache(past_key_values, beam_idx):
reordered_past = ()
for layer_past in past_key_values:
reordered_past += (
tuple(past_state.index_select(0, beam_idx.to(past_state.device)) for past_state in layer_past),
)
return reordered_past
@add_start_docstrings(
"""
The LongLLaMA Model transformer with a sequence classification head on top (linear layer).
[`LongLlamaForSequenceClassification`] uses the last token in order to do the classification, as other causal models
(e.g. GPT-2) do.
Since it does classification on the last token, it requires to know the position of the last token. If a
`pad_token_id` is defined in the configuration, it finds the last token that is not a padding token in each row. If
no `pad_token_id` is defined, it simply takes the last value in each row of the batch. Since it cannot guess the
padding tokens when `inputs_embeds` are passed instead of `input_ids`, it does the same (take the last value in
each row of the batch).
""",
LONGLLAMA_START_DOCSTRING,
LONGLLAMA_MEML_DOCSTRING,
)
# Modified from transformers.models.llama.modeling_llama.LlamaForSequenceClassification
class LongLlamaForSequenceClassification(LongLlamaPreTrainedModel):
_keys_to_ignore_on_load_missing = [r"lm_head.weight"]
def __init__(self, config):
super().__init__(config)
self.num_labels = config.num_labels
self.context_window_length = config.max_position_embeddings
self.model = LongLlamaModel(config)
self.score = nn.Linear(config.hidden_size, self.num_labels, bias=False)
# Initialize weights and apply final processing
self.post_init()
def get_input_embeddings(self):
return self.model.embed_tokens
def set_input_embeddings(self, value):
self.model.embed_tokens = value
@add_start_docstrings_to_model_forward(LONGLLAMA_COMMON_INPUTS_DOCSTRING, LONGLLAMA_ADD_INPUTS_DOCSTRING)
def forward(
self,
input_ids: torch.LongTensor = None,
attention_mask: Optional[torch.Tensor] = None,
position_ids: Optional[torch.LongTensor] = None,
past_key_values: Optional[List[torch.FloatTensor]] = None,
inputs_embeds: Optional[torch.FloatTensor] = None,
labels: Optional[torch.LongTensor] = None,
use_cache: Optional[bool] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
last_context_length: Optional[int] = None,
) -> Union[Tuple, SequenceClassifierOutputWithPast]:
r"""
labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
Labels for computing the sequence classification/regression loss. Indices should be in `[0, ...,
config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
`config.num_labels > 1` a classification loss is computed (Cross-Entropy).
"""
last_context_length = (
last_context_length if last_context_length is not None else self.config.last_context_length
)
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
output_hidden_states = (
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
)
transformer_outputs = _handle_long_input(
model=self.model,
input_ids=input_ids,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
use_cache=use_cache,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
context_window_length=self.context_window_length,
last_context_length=last_context_length,
)
hidden_states = transformer_outputs[0]
logits = self.score(hidden_states)
if input_ids is not None:
batch_size = input_ids.shape[0]
else:
batch_size = inputs_embeds.shape[0]
if self.config.pad_token_id is None and batch_size != 1:
raise ValueError("Cannot handle batch sizes > 1 if no padding token is defined.")
if self.config.pad_token_id is None:
sequence_lengths = -1
else:
if input_ids is not None:
sequence_lengths = (torch.ne(input_ids, self.config.pad_token_id).sum(-1) - 1).to(logits.device)
else:
sequence_lengths = -1
pooled_logits = logits[torch.arange(batch_size, device=logits.device), sequence_lengths]
loss = None
if labels is not None:
labels = labels.to(logits.device)
if self.config.problem_type is None:
if self.num_labels == 1:
self.config.problem_type = "regression"
elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int):
self.config.problem_type = "single_label_classification"
else:
self.config.problem_type = "multi_label_classification"
if self.config.problem_type == "regression":
loss_fct = MSELoss()
if self.num_labels == 1:
loss = loss_fct(pooled_logits.squeeze(), labels.squeeze())
else:
loss = loss_fct(pooled_logits, labels)
elif self.config.problem_type == "single_label_classification":
loss_fct = CrossEntropyLoss()
loss = loss_fct(pooled_logits.view(-1, self.num_labels), labels.view(-1))
elif self.config.problem_type == "multi_label_classification":
loss_fct = BCEWithLogitsLoss()
loss = loss_fct(pooled_logits, labels)
if not return_dict:
output = (pooled_logits,) + transformer_outputs[1:]
return ((loss,) + output) if loss is not None else output
return SequenceClassifierOutputWithPast(
loss=loss,
logits=pooled_logits,
past_key_values=transformer_outputs.past_key_values,
hidden_states=transformer_outputs.hidden_states,
attentions=transformer_outputs.attentions,
)