llama-stack/llama_stack/models/llama/llama3/multimodal/model.py

1435 lines
50 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# the root directory of this source tree.
# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the terms described in the LICENSE file in
# top-level folder for each specific model found within the models/ directory at
# the top-level of this source tree.
# Copyright (c) Meta Platforms, Inc. and affiliates.
# This software may be used and distributed according to the terms of the Llama 2 Community License Agreement.
import logging
import math
from functools import partial
from typing import Any, Callable, Dict, List, Optional, Tuple, Union
import fairscale.nn.model_parallel.initialize as fs_init
import torch
import torch.nn.functional as F
from fairscale.nn.model_parallel.layers import (
ColumnParallelLinear,
RowParallelLinear,
VocabParallelEmbedding,
)
from PIL import Image as PIL_Image
from torch import Tensor, nn
from torch.distributed import _functional_collectives as funcol
from ..model import ModelArgs, RMSNorm, apply_rotary_emb, precompute_freqs_cis
from .encoder_utils import (
build_encoder_attention_mask,
contract_num_tokens_from_mult8,
expand_num_tokens_to_mult8,
initialize_global_position_embedding_from_local,
resize_global_position_embedding,
resize_local_position_embedding,
)
from .image_transform import VariableSizeImageTransform
from .utils import get_negative_inf_value, to_2tuple
logger = logging.getLogger(__name__)
MP_SCALE = 8
def reduce_from_tensor_model_parallel_region(input_):
"""All-reduce the input tensor across model parallel group."""
output = funcol.all_reduce(input_, "sum", group=fs_init.get_model_parallel_group())
output = funcol.wait_tensor(output)
return output
def gather_from_tensor_model_parallel_region(input_):
"""Gather tensors and concatenate along the last dimension."""
world_size = fs_init.get_model_parallel_world_size()
# Size and dimension.
last_dim = input_.dim() - 1
rank = fs_init.get_model_parallel_rank()
tensor_list = [torch.empty_like(input_) for _ in range(world_size)]
tensor_list[rank] = input_
output = funcol.all_gather_tensor(
input_,
gather_dim=last_dim,
group=fs_init.get_model_parallel_group(),
)
output = funcol.wait_tensor(output)
return output
def _get_full_row_masked_out_mask(
attn_bias,
negative_inf_value,
):
"""
attn_bias should be a 4D tensor of shape [B, H, S1, S2]
where B is the batch size, H is the number of heads,
and S1/S2 are the sequence lengths. This returns
a 4D tensor of shape [B, H, S1, 1] which stores boolean
values which are 0 if the a full row in the last dimension
contains negative infinity values, otherwise it's 1.
"""
return (attn_bias != negative_inf_value).any(dim=-1).type_as(attn_bias)[..., None]
# Image encoder for inference
class LayerNorm(nn.LayerNorm):
"""Subclass torch's LayerNorm to handle fp16."""
def forward(self, x: torch.Tensor):
x = F.layer_norm(x, self.normalized_shape, self.weight, self.bias, self.eps)
return x
class ColumnParallelConv2dPatch(torch.nn.Module):
"""Conv2D Patching layer with model parallelism.
Column parallel over unfolded input.
Arguments:
in_channels: Input channels.
out_channels: Output channels.
kernel_size: Size of convolution kernel.
stride (default 1): Stride for convolution.
bias (default False): Use bias in Conv2d.
Input: (bsz, in_channels, width, height)
Output: (bsz, num_tokens, out_channels)
"""
def __init__(
self,
in_channels: int,
out_channels: int,
kernel_size: Union[int, Tuple[int, int]],
stride: Union[int, Tuple[int, int]],
bias: Optional[bool] = False,
) -> None:
super().__init__()
if isinstance(kernel_size, int):
kernel_size = (kernel_size, kernel_size)
self._unfold = torch.nn.Unfold(kernel_size=kernel_size, stride=stride)
self._linear = ColumnParallelLinear(
in_channels * kernel_size[0] * kernel_size[1],
out_channels,
bias=bias,
)
def forward(self, x: torch.Tensor) -> torch.Tensor:
x = self._unfold(x)
x = x.permute(0, 2, 1)
x = F.linear(x, self._linear.weight)
x = gather_from_tensor_model_parallel_region(x)
return x
class ImageFeedForward(torch.nn.Module):
def __init__(
self,
dim: int,
hidden_dim: int,
dropout: float,
act_layer: Callable = nn.GELU,
):
super().__init__()
# layers
self.c_fc = ColumnParallelLinear(
dim,
hidden_dim,
bias=True,
gather_output=False,
init_method=lambda x: x,
)
self.c_proj = RowParallelLinear(
hidden_dim,
dim,
bias=True,
input_is_parallel=True,
init_method=lambda x: x,
)
self.non_linearity = act_layer()
self.dropout = dropout
def forward(self, x):
hidden = F.linear(x, self.c_fc.weight, self.c_fc.bias)
hidden = self.non_linearity(hidden)
hidden = F.linear(hidden, self.c_proj.weight)
hidden = reduce_from_tensor_model_parallel_region(hidden)
hidden += self.c_proj.bias
return hidden
class ImageAttention(nn.Module):
def __init__(
self,
dim,
head_dim,
n_heads,
):
super().__init__()
model_parallel_size = fs_init.get_model_parallel_world_size()
qkvo_replication = 1
if model_parallel_size > 16:
qkvo_replication = model_parallel_size // 8
self.n_kv_heads = n_heads
self.n_local_heads = n_heads * qkvo_replication // model_parallel_size
self.n_local_kv_heads = self.n_kv_heads * qkvo_replication // model_parallel_size
self.n_rep = self.n_local_heads // self.n_local_kv_heads
self.head_dim = dim // n_heads
self.wq = ColumnParallelLinear(
dim,
qkvo_replication * n_heads * self.head_dim,
bias=False,
gather_output=False,
init_method=lambda x: x,
)
self.wk = ColumnParallelLinear(
dim,
qkvo_replication * self.n_kv_heads * self.head_dim,
bias=False,
gather_output=False,
init_method=lambda x: x,
)
self.wv = ColumnParallelLinear(
dim,
qkvo_replication * self.n_kv_heads * self.head_dim,
bias=False,
gather_output=False,
init_method=lambda x: x,
)
self.wo = RowParallelLinear(
qkvo_replication * n_heads * self.head_dim,
dim,
bias=False,
input_is_parallel=True,
init_method=lambda x: x,
)
self.qkvo_replication = qkvo_replication
def forward(
self,
x: torch.Tensor,
mask: torch.Tensor = None,
):
xq, xk, xv = [F.linear(x, w) for w in [self.wq.weight, self.wk.weight, self.wv.weight]]
bs, slen, _ = xq.shape
xq = xq.view(bs, slen, self.n_local_heads, self.head_dim)
xk = xk.view(bs, xk.shape[1], self.n_local_kv_heads, self.head_dim)
xv = xv.view(bs, xv.shape[1], self.n_local_kv_heads, self.head_dim)
xq, xk, xv = [tensor.transpose(1, 2) for tensor in (xq, xk, xv)]
xk = xk.repeat_interleave(self.n_rep, dim=1)
xv = xv.repeat_interleave(self.n_rep, dim=1)
attn_output = F.scaled_dot_product_attention(xq, xk, xv, attn_mask=mask, dropout_p=0.0)
attn_output = attn_output.transpose(1, 2).contiguous().reshape(bs, slen, -1)
out = F.linear(attn_output, self.wo.weight)
out = reduce_from_tensor_model_parallel_region(out)
out = out / self.qkvo_replication
return out
class ImageTransformerBlock(nn.Module):
def __init__(
self,
d_model: int,
n_head: int,
mlp_ratio: float = 4.0,
act_layer: Callable = nn.GELU,
gated: bool = False,
):
super().__init__()
assert d_model % n_head == 0
self.n_heads = n_head
self.head_dim = d_model // self.n_heads
self.attn = ImageAttention(
dim=d_model,
head_dim=self.head_dim,
n_heads=self.n_heads,
)
self.ln_1 = LayerNorm(d_model)
self.mlp = ImageFeedForward(
dim=d_model,
hidden_dim=int(mlp_ratio * d_model),
dropout=0.0,
act_layer=act_layer,
)
self.ln_2 = LayerNorm(d_model)
self.gated = gated
if gated:
self.gate_attn = nn.Parameter(torch.zeros(1))
self.gate_ffn = nn.Parameter(torch.zeros(1))
def forward(
self,
x: torch.Tensor,
mask: torch.Tensor = None,
):
_gate_attn = 1 if not self.gated else self.gate_attn.tanh()
_gate_ffn = 1 if not self.gated else self.gate_ffn.tanh()
x = x + _gate_attn * self.attn(self.ln_1(x), mask=mask)
x = x + _gate_ffn * self.mlp(self.ln_2(x))
return x
class ImageTransformer(nn.Module):
def __init__(
self,
width: int,
layers: int,
heads: int,
mlp_ratio: float = 4.0,
act_layer: Callable = nn.GELU,
gated: bool = False,
):
super().__init__()
self.width = width
self.layers = layers
self.resblocks = nn.ModuleList(
[
ImageTransformerBlock(
d_model=width,
n_head=heads,
mlp_ratio=mlp_ratio,
act_layer=act_layer,
gated=gated,
)
for _ in range(self.layers)
]
)
def forward(self, x: torch.Tensor, return_intermediate=None, mask=None):
out = []
for idx, r in enumerate(self.resblocks):
if return_intermediate is not None and idx in return_intermediate:
out.append(x)
x = r(x, mask=mask)
if return_intermediate is not None:
return x, torch.stack(out, dim=-1)
return x
class VisionEncoder(nn.Module):
def __init__(
self,
max_num_tiles: int,
ckpt_path: str = None,
image_size: int = 224,
patch_size: int = 14,
width: int = 1280,
layers: int = 32,
heads: int = 16,
mlp_ratio: float = 4.0,
act_layer: Callable = nn.GELU,
in_channels: int = 3,
load_ckpt: bool = False,
n_global_layers: int = 2,
global_model: bool = False,
return_intermediate=None,
):
super().__init__()
self.global_model = global_model
self.return_intermediate = return_intermediate
self.max_num_tiles = max_num_tiles
self.image_size = to_2tuple(image_size)
self.patch_size = to_2tuple(patch_size)
self.grid_size = (
self.image_size[0] // self.patch_size[0],
self.image_size[1] // self.patch_size[1],
)
self.conv1 = ColumnParallelConv2dPatch(
in_channels=in_channels,
out_channels=width,
kernel_size=patch_size,
stride=patch_size,
bias=False,
)
scale = width**-0.5
self.class_embedding = nn.Parameter(scale * torch.randn(width))
self.positional_embedding = nn.Parameter(scale * torch.randn(self.grid_size[0] * self.grid_size[1] + 1, width))
self.ln_post = LayerNorm(width)
self.ln_pre = LayerNorm(width)
self.transformer = ImageTransformer(width, layers, heads, mlp_ratio, act_layer=act_layer)
# pre and post tile position embedding
self.global_transformer = ImageTransformer(
width, n_global_layers, heads, mlp_ratio, act_layer=act_layer, gated=True
)
# pre and post tile position embedding
self.pre_tile_pos_embed = TilePositionEmbedding(
num_tiles=max_num_tiles,
width=width,
gated=True,
)
self.post_tile_pos_embed = TilePositionEmbedding(
num_tiles=max_num_tiles,
width=width,
gated=True,
)
self.gated_positional_embedding = nn.Parameter(
scale
* torch.randn(
max_num_tiles,
max_num_tiles,
self.grid_size[0] * self.grid_size[1] + 1,
width,
)
)
self.gated_positional_embedding_gate = nn.Parameter(torch.zeros(1))
self._register_load_state_dict_pre_hook(self.load_hook)
def load_hook(
self,
state_dict: Dict[str, Any],
prefix: str,
local_metadata: Dict[str, Any],
strict: bool = True,
missing_keys: List[str] = None,
unexpected_keys: List[str] = None,
error_msgs: List[str] = None,
return_state_dict: bool = False,
) -> None:
orig_pos_embed = state_dict.get(prefix + "positional_embedding")
if orig_pos_embed is not None:
new_pos_embed = resize_local_position_embedding(orig_pos_embed, self.grid_size)
state_dict[prefix + "positional_embedding"] = new_pos_embed
if hasattr(self, "gated_positional_embedding"):
if prefix + "gated_positional_embedding" not in state_dict:
# resize positional_embedding to fit the new grid size
global_pos_embed = initialize_global_position_embedding_from_local(
new_pos_embed,
self.grid_size,
self.max_num_tiles,
self.max_num_tiles,
)
state_dict[prefix + "gated_positional_embedding"] = global_pos_embed
state_dict[prefix + "gated_positional_embedding_gate"] = torch.zeros(1, dtype=global_pos_embed.dtype)
logger.info(f"Initialized global positional embedding with size {global_pos_embed.size()}")
else:
global_pos_embed = resize_global_position_embedding(
state_dict[prefix + "gated_positional_embedding"],
self.grid_size,
self.max_num_tiles,
self.max_num_tiles,
)
logger.info(
f"Resized global positional embedding from {state_dict[prefix + 'gated_positional_embedding'].size()} to {global_pos_embed.size()}"
)
state_dict[prefix + "gated_positional_embedding"] = global_pos_embed
if return_state_dict:
return state_dict
def apply_positional_embedding(self, x, ar):
# apply regular position embedding
bsz, num_chunks, num_tokens, dim = x.shape
x = x.view(bsz * num_chunks, num_tokens, dim)
x = x + self.positional_embedding * (1 - self.gated_positional_embedding_gate.tanh())
x = x.view(bsz, num_chunks, num_tokens, dim)
for idx, arx in enumerate(ar):
_pos_embed = self.gated_positional_embedding[: arx[0], : arx[1]]
_pos_embed = _pos_embed.reshape(arx[0] * arx[1], *_pos_embed.shape[2:])
x[idx, : arx[0] * arx[1]] += _pos_embed * self.gated_positional_embedding_gate.tanh()
return x
def apply_class_embedding(self, x):
x = torch.cat(
[
self.class_embedding.to(x.dtype)
+ torch.zeros(x.shape[0], 1, x.shape[-1], dtype=x.dtype, device=x.device),
x,
],
dim=1,
) # shape = [*, grid ** 2 + 1, width]
return x
def forward(self, images: torch.Tensor, ar: torch.Tensor) -> torch.Tensor:
if images.ndim == 5:
num_concurrent_media = 1
bsz, num_chunks, nch, w, h = images.shape
else:
bsz, num_concurrent_media, num_chunks, nch, w, h = images.shape
images = images.reshape(bsz * num_concurrent_media * num_chunks, nch, w, h)
ar = ar.reshape(bsz * num_concurrent_media, 2)
# patch embedding
x = images.reshape(bsz * num_concurrent_media * num_chunks, nch, w, h)
x = self.conv1(x) # shape = [*, width, grid ** 2]
_, ntok, dim = x.shape
x = x.reshape(bsz * num_concurrent_media, num_chunks, ntok, dim)
# tile embeddings
x = self.pre_tile_pos_embed(x, ar)
x = x.reshape(bsz * num_concurrent_media * num_chunks, ntok, dim)
# apply cls token
x = self.apply_class_embedding(x)
ntok += 1
# apply position embeddings
x = x.reshape(bsz * num_concurrent_media, num_chunks, ntok, dim)
x = self.apply_positional_embedding(x, ar)
x = self.ln_pre(x)
npad, attn_mask = 0, None
x, npad = expand_num_tokens_to_mult8(x)
attn_mask = build_encoder_attention_mask(x, ar, ntok, num_chunks, 1)
x = x.view(bsz * num_concurrent_media, -1, dim)
x, int_x = self.transformer(x, return_intermediate=self.return_intermediate, mask=attn_mask)
x = self.ln_post(x)
x = x.reshape(bsz * num_concurrent_media, num_chunks, ntok + npad, dim)
x = self.post_tile_pos_embed(x, ar)
x = x.reshape(bsz * num_concurrent_media, num_chunks * (ntok + npad), dim)
x = self.global_transformer(x, mask=attn_mask)
x = x.reshape(bsz * num_concurrent_media, num_chunks, ntok + npad, dim)
x = contract_num_tokens_from_mult8(x, npad)
# adding back intermediate layer outputs
x = x.reshape(bsz, num_concurrent_media, num_chunks, ntok, dim)
int_x = int_x.reshape(bsz * num_concurrent_media, num_chunks, ntok + npad, -1)
int_x = contract_num_tokens_from_mult8(int_x, npad)
int_x = int_x.reshape(bsz, num_concurrent_media, num_chunks, ntok, -1)
x = torch.cat([x, int_x], dim=-1)
return x
class Attention(nn.Module):
"""Multi-head attention module."""
def __init__(self, args: ModelArgs):
"""
Initialize the Attention module.
Args:
args (ModelArgs): Model configuration parameters.
Attributes:
n_kv_heads (int): Number of key and value heads.
n_local_heads (int): Number of local query heads.
n_local_kv_heads (int): Number of local key and value heads.
n_rep (int): Number of repetitions for local heads.
head_dim (int): Dimension size of each attention head.
wq (ColumnParallelLinear): Linear transformation for queries.
wk (ColumnParallelLinear): Linear transformation for keys.
wv (ColumnParallelLinear): Linear transformation for values.
wo (RowParallelLinear): Linear transformation for output.
cache_k (torch.Tensor): Cached keys for attention.
cache_v (torch.Tensor): Cached values for attention.
"""
super().__init__()
model_parallel_size = fs_init.get_model_parallel_world_size()
replication_factor = 1
if model_parallel_size > 8:
replication_factor = model_parallel_size // MP_SCALE
self.n_kv_heads = args.n_heads if args.n_kv_heads is None else args.n_kv_heads
self.n_kv_heads *= replication_factor
self.n_local_heads = args.n_heads // model_parallel_size
self.n_local_kv_heads = self.n_kv_heads // model_parallel_size
self.n_rep = self.n_local_heads // self.n_local_kv_heads
self.head_dim = args.dim // args.n_heads
self.max_seq_len = args.max_seq_len
self.wq = ColumnParallelLinear(
args.dim,
args.n_heads * self.head_dim,
bias=False,
gather_output=False,
init_method=lambda x: x,
)
self.wk = ColumnParallelLinear(
args.dim,
self.n_kv_heads * self.head_dim,
bias=False,
gather_output=False,
init_method=lambda x: x,
)
self.wv = ColumnParallelLinear(
args.dim,
self.n_kv_heads * self.head_dim,
bias=False,
gather_output=False,
init_method=lambda x: x,
)
self.wo = RowParallelLinear(
args.n_heads * self.head_dim,
args.dim,
bias=False,
input_is_parallel=True,
init_method=lambda x: x,
)
self.n_heads = args.n_heads
def setup_cache(self, max_batch_size: int, dtype: torch.dtype):
cache_shape = (
max_batch_size,
self.max_seq_len,
self.n_local_kv_heads,
self.head_dim,
)
device = next(self.parameters()).device
self.register_buffer(
"key_cache",
torch.zeros(
cache_shape,
dtype=dtype,
device=device,
),
persistent=False,
)
self.register_buffer(
"value_cache",
torch.zeros(
cache_shape,
dtype=dtype,
device=device,
),
persistent=False,
)
def forward(
self,
x: torch.Tensor,
mask: torch.Tensor,
freqs_cis: torch.Tensor,
position_ids: torch.LongTensor,
):
xq, xk, xv = [F.linear(x, w) for w in [self.wq.weight, self.wk.weight, self.wv.weight]]
bs, slen, _ = xq.shape
xq = xq.view(bs, slen, self.n_local_heads, self.head_dim)
xk = xk.view(bs, xk.shape[1], self.n_local_kv_heads, self.head_dim)
xv = xv.view(bs, xv.shape[1], self.n_local_kv_heads, self.head_dim)
xq, xk = apply_rotary_emb(xq, xk, freqs_cis)
self.key_cache[:bs, position_ids, ...] = xk
self.value_cache[:bs, position_ids, ...] = xv
# TODO: we can avoid slicing on first dimension by always padding to max_batch_size()
xk = self.key_cache[:bs, ...]
xv = self.value_cache[:bs, ...]
xq, xk, xv = [tensor.transpose(1, 2) for tensor in (xq, xk, xv)]
xk = xk.repeat_interleave(self.n_rep, dim=1)
xv = xv.repeat_interleave(self.n_rep, dim=1)
attn_output = F.scaled_dot_product_attention(xq, xk, xv, attn_mask=mask, dropout_p=0.0)
attn_output = attn_output.transpose(1, 2).contiguous().reshape(bs, slen, -1)
out = F.linear(attn_output, self.wo.weight)
out = reduce_from_tensor_model_parallel_region(out)
return out
class FeedForward(nn.Module):
def __init__(
self,
dim: int,
hidden_dim: int,
multiple_of: int,
ffn_dim_multiplier: Optional[float],
):
"""
Initialize the FeedForward module.
Args:
dim (int): Input dimension.
hidden_dim (int): Hidden dimension of the feedforward layer.
multiple_of (int): Value to ensure hidden dimension is a multiple of this value.
ffn_dim_multiplier (float, optional): Custom multiplier for hidden dimension. Defaults to None.
Attributes:
w1 (ColumnParallelLinear): Linear transformation for the first layer.
w2 (RowParallelLinear): Linear transformation for the second layer.
w3 (ColumnParallelLinear): Linear transformation for the third layer.
"""
super().__init__()
hidden_dim = int(2 * hidden_dim / 3)
# custom dim factor multiplier
if ffn_dim_multiplier is not None:
hidden_dim = int(ffn_dim_multiplier * hidden_dim)
hidden_dim = multiple_of * ((hidden_dim + multiple_of - 1) // multiple_of)
self.w1 = ColumnParallelLinear(dim, hidden_dim, bias=False, gather_output=False, init_method=lambda x: x)
self.w2 = RowParallelLinear(hidden_dim, dim, bias=False, input_is_parallel=True, init_method=lambda x: x)
self.w3 = ColumnParallelLinear(dim, hidden_dim, bias=False, gather_output=False, init_method=lambda x: x)
def forward(self, x):
x1, x3 = [F.linear(x, w) for w in [self.w1.weight, self.w3.weight]]
x1 = F.silu(x1)
x_in = x1 * x3
out = F.linear(x_in, self.w2.weight)
out = reduce_from_tensor_model_parallel_region(out)
return out
class TransformerBlock(nn.Module):
def __init__(self, layer_id: int, args: ModelArgs):
"""
Initialize a TransformerBlock.
Args:
layer_id (int): Identifier for the layer.
args (ModelArgs): Model configuration parameters.
Attributes:
n_heads (int): Number of attention heads.
dim (int): Dimension size of the model.
head_dim (int): Dimension size of each attention head.
attention (Attention): Attention module.
feed_forward (FeedForward): FeedForward module.
layer_id (int): Identifier for the layer.
attention_norm (RMSNorm): Layer normalization for attention output.
ffn_norm (RMSNorm): Layer normalization for feedforward output.
"""
super().__init__()
self.n_heads = args.n_heads
self.dim = args.dim
self.head_dim = args.dim // args.n_heads
self.attention = Attention(args)
self.feed_forward = FeedForward(
dim=args.dim,
hidden_dim=4 * args.dim,
multiple_of=args.multiple_of,
ffn_dim_multiplier=args.ffn_dim_multiplier,
)
self.layer_id = layer_id
self.attention_norm = RMSNorm(args.dim, eps=args.norm_eps)
self.ffn_norm = RMSNorm(args.dim, eps=args.norm_eps)
def setup_cache(self, max_batch_size: int, dtype: torch.dtype):
self.attention.setup_cache(max_batch_size, dtype)
def forward(
self,
x: torch.Tensor,
freqs_cis: torch.Tensor,
mask: torch.Tensor,
position_ids: torch.LongTensor,
) -> torch.Tensor:
"""
Perform a forward pass through the TransformerBlock.
Args:
x (torch.Tensor): Input tensor.
start_pos (int): Starting position for attention caching.
freqs_cis (torch.Tensor): Precomputed cosine and sine frequencies.
mask (torch.Tensor, optional): Masking tensor for attention. Defaults to None.
Returns:
torch.Tensor: Output tensor after applying attention and feedforward layers.
"""
h = self.attention.forward(
x=self.attention_norm(x),
freqs_cis=freqs_cis,
mask=mask,
position_ids=position_ids,
)
h = h + x
out = h + self.feed_forward.forward(self.ffn_norm(h))
return out
class TilePositionEmbedding(nn.Module):
def __init__(
self,
num_tiles: int,
width: int,
gated: bool = False,
):
super().__init__()
self.num_tiles = num_tiles
self.width = width
self.embedding = nn.Parameter(torch.randn(num_tiles, num_tiles, 1, width) / math.sqrt(width))
self.gated = gated
if gated:
self.gate = nn.Parameter(torch.zeros(1))
self._register_load_state_dict_pre_hook(self.load_hook)
def load_hook(
self,
state_dict,
prefix,
local_metadata,
strict,
missing_keys,
unexpected_keys,
error_msgs,
):
# load the weights from the checkpoint
embed = state_dict.get(prefix + "embedding")
if embed is not None:
# reshape the weights to the correct shape
nt_old, nt_old, _, w = embed.shape
logging.info(f"Resizing tile embedding from {nt_old}x{nt_old} to {self.num_tiles}x{self.num_tiles}")
embed_new = TilePositionEmbedding._dynamic_resize(embed, self.num_tiles)
# assign the weights to the module
state_dict[prefix + "embedding"] = embed_new
@staticmethod
def _dynamic_resize(embed: torch.Tensor, num_tiles: int):
nt_old, nt_old, _, w = embed.shape
embed = embed.permute(2, 3, 0, 1)
embed_new = F.interpolate(
embed,
size=(num_tiles, num_tiles),
mode="bilinear",
align_corners=True,
)
# reshape the weights to the correct shape
embed_new = embed_new.permute(2, 3, 0, 1)
return embed_new
def forward(self, x: torch.Tensor, ar: torch.Tensor, num_tiles: int = None):
embed = self.embedding
if num_tiles is None:
num_tiles = self.num_tiles
elif num_tiles > self.num_tiles:
embed = TilePositionEmbedding._dynamic_resize(self.embedding, num_tiles)
out_pos_embed = torch.zeros(x.shape[0], num_tiles, 1, self.width, device=x.device, dtype=x.dtype)
for idx, arx in enumerate(ar):
h, w = arx
out_pos_embed[idx, : w * h] = embed[:h, :w].reshape(w * h, 1, self.width)
if self.gated:
out_pos_embed = out_pos_embed * self.gate.tanh()
x = x + out_pos_embed
return x
def _noinit(x):
return x
class CrossAttention(torch.nn.Module):
"""Cross attention layer with model-parallel attention layers."""
def __init__(
self,
dim: int,
head_dim: int,
n_heads: int,
n_kv_heads: int,
norm_eps: float,
):
super().__init__()
self.model_parallel_size = fs_init.get_model_parallel_world_size()
replication_factor = 1
if self.model_parallel_size > 8:
replication_factor = self.model_parallel_size // MP_SCALE
n_kv_heads *= replication_factor
assert n_heads % n_kv_heads == 0
self.wq = ColumnParallelLinear(
dim,
n_heads * head_dim,
bias=False,
gather_output=False,
init_method=_noinit,
)
self.wk = ColumnParallelLinear(
dim,
n_kv_heads * head_dim,
bias=False,
gather_output=False,
init_method=_noinit,
)
self.wv = ColumnParallelLinear(
dim,
n_kv_heads * head_dim,
bias=False,
gather_output=False,
init_method=_noinit,
)
self.wo = RowParallelLinear(
n_heads * head_dim,
dim,
bias=False,
input_is_parallel=True,
init_method=_noinit,
)
self.n_heads = n_heads
self.head_dim = head_dim
self.n_kv_heads = n_kv_heads
self.q_norm = RMSNorm(
self.head_dim,
eps=norm_eps,
)
self.k_norm = RMSNorm(
self.head_dim,
eps=norm_eps,
)
# cross-attention heads are model parallel similar to
# self-attention, and we also use the identical KV head
# combination to ensure parity with the corresponding
# trunk LLM (i.e., group query attention) -- @dubeya
# local heads
assert self.n_heads % self.n_kv_heads == 0
assert self.n_heads % self.model_parallel_size == 0
assert self.n_kv_heads % self.model_parallel_size == 0
self.n_local_heads = self.n_heads // self.model_parallel_size
self.n_local_kv_heads = self.n_kv_heads // self.model_parallel_size
self.n_rep = self.n_local_heads // self.n_local_kv_heads
def _compute_xattn_kv_cache(self, xattn_tokens: torch.Tensor) -> torch.Tensor:
bsz = xattn_tokens.shape[0]
xk = self.wk(xattn_tokens)
xv = self.wv(xattn_tokens)
_, seqlen_y, _ = xk.shape
xk = xk.view(bsz, seqlen_y, self.n_local_kv_heads, self.head_dim)
xv = xv.view(bsz, seqlen_y, self.n_local_kv_heads, self.head_dim)
xk, xv = [tensor.transpose(1, 2) for tensor in (xk, xv)]
# repeat k/v heads if n_kv_heads < n_heads
xk = xk.repeat_interleave(self.n_rep, dim=1)
xv = xv.repeat_interleave(self.n_rep, dim=1)
xk = self.k_norm(xk)
return torch.stack([xk, xv])
def compute_xattn_kv_cache(self, xattn_tokens: torch.Tensor) -> torch.Tensor:
return self._compute_xattn_kv_cache(xattn_tokens)
def forward(
self,
x: torch.Tensor,
xattn_mask: torch.Tensor,
full_text_row_masked_out_mask: torch.Tensor,
xattn_cache: torch.Tensor,
) -> torch.Tensor:
xq = F.linear(x, self.wq.weight)
bsz, seqlen, _ = x.shape
xq = xq.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xq = self.q_norm(xq)
xq = xq.transpose(1, 2)
xk, xv = xattn_cache
output = F.scaled_dot_product_attention(xq, xk, xv, attn_mask=xattn_mask, dropout_p=0.0)
output = output * full_text_row_masked_out_mask
output = output.transpose(1, 2).contiguous().reshape(bsz, seqlen, -1)
out = F.linear(output, self.wo.weight)
out = reduce_from_tensor_model_parallel_region(out)
return out
class CrossAttentionTransformerBlock(torch.nn.Module):
"""Cross-attention transformer block with tanh-gated attention and feedforward."""
def __init__(
self,
args: ModelArgs,
layer_id: int,
no_ffn: bool = False,
) -> None:
super().__init__()
self.layer_id = layer_id
self.n_heads = args.n_heads
self.n_kv_heads = args.n_heads if args.n_kv_heads is None else args.n_kv_heads
self.dim = args.dim
self.head_dim = args.dim // args.n_heads
self.attention = CrossAttention(
dim=args.dim,
head_dim=self.head_dim,
n_heads=self.n_heads,
n_kv_heads=self.n_kv_heads,
norm_eps=args.norm_eps,
)
self.attention_norm = RMSNorm(
args.dim,
eps=args.norm_eps,
)
self.gate_attn = torch.nn.Parameter(torch.zeros(1))
self.feed_forward = FeedForward(
dim=args.dim,
hidden_dim=4 * args.dim,
ffn_dim_multiplier=args.ffn_dim_multiplier,
multiple_of=args.multiple_of,
)
self.ffn_norm = RMSNorm(
args.dim,
eps=args.norm_eps,
)
self.gate_ffwd = torch.nn.Parameter(torch.zeros(1))
self.no_ffn = no_ffn
def compute_xattn_kv_cache(self, xattn_tokens: torch.Tensor) -> torch.Tensor:
return self.attention.compute_xattn_kv_cache(xattn_tokens)
def forward(
self,
x: torch.Tensor,
xattn_mask: torch.Tensor,
full_text_row_masked_out_mask: Tuple[torch.Tensor, torch.Tensor],
xattn_cache: torch.Tensor,
) -> torch.Tensor:
_attn_out = self.attention(
x=self.attention_norm(x),
xattn_mask=xattn_mask,
xattn_cache=xattn_cache,
full_text_row_masked_out_mask=full_text_row_masked_out_mask,
)
h = x + self.gate_attn.tanh() * _attn_out
_ffn = self.feed_forward(self.ffn_norm(h))
_ffn = full_text_row_masked_out_mask[:, 0] * _ffn # type: ignore
h = h + self.gate_ffwd.tanh() * _ffn * float(not self.no_ffn)
return h
class DummyCrossAttentionTransformerBlock:
"""Dummy cross-attention transformer block with tanh-gated attention and feedforward."""
def __call__(
self,
x: torch.Tensor,
*args,
**kwargs,
) -> torch.Tensor:
return x
class DummySelfAttentionTransformerBlock:
"""Dummy self-attention transformer block"""
def __call__(
self,
x: torch.Tensor,
*args,
**kwargs,
) -> torch.Tensor:
return x
class CrossAttentionTransformerVision(torch.nn.Module):
def __init__(self, args: ModelArgs) -> None:
super().__init__()
return_intermediate = "3,7,15,23,30"
self.vision_input_dim = 1280
self.image_res = args.vision_chunk_size
self.max_num_chunks = args.vision_max_num_chunks
if return_intermediate is not None:
return_intermediate = [int(level) for level in return_intermediate.split(",")]
self.vision_input_dim = (len(return_intermediate) + 1) * self.vision_input_dim
self.patch_size = 14
self.vision_encoder = VisionEncoder(
max_num_tiles=4,
image_size=args.vision_chunk_size,
patch_size=self.patch_size,
n_global_layers=8,
global_model=True,
return_intermediate=return_intermediate,
)
# vision token projection
self.vision_projection = ColumnParallelLinear(
self.vision_input_dim,
args.dim,
bias=True,
init_method=lambda x: x,
)
def forward(self, images: torch.Tensor, aspect_ratios: torch.Tensor) -> torch.Tensor:
# vision_tokens: (B, T, D)
# aspect_ratios: (B, T)
# h: (B, T, D)
vision_tokens = self.vision_encoder(images.to(dtype=torch.get_default_dtype()), aspect_ratios)
vision_tokens = F.linear(vision_tokens, self.vision_projection.weight, self.vision_projection.bias)
vision_tokens = gather_from_tensor_model_parallel_region(vision_tokens)
return vision_tokens
class CrossAttentionTransformerText(torch.nn.Module):
INFERENCE_IMAGE_TOKEN_ID = 128010
def __init__(self, args: ModelArgs) -> None:
super().__init__()
self.model_parallel_size = fs_init.get_model_parallel_world_size()
assert args.vocab_size > 0
self.vocab_size = args.vocab_size
self.n_layers = args.n_layers
self.dim = args.dim
self.head_dim = args.dim // args.n_heads
self.n_kv_heads = args.n_heads if args.n_kv_heads is None else args.n_kv_heads
self.n_local_kv_heads = self.n_kv_heads // self.model_parallel_size
assert self.vocab_size % self.model_parallel_size == 0
self.tok_embeddings = VocabParallelEmbedding(args.vocab_size, args.dim, init_method=lambda x: x)
self.pos_embeddings = None
# final norm layer (not necessary for post-norm)
self.norm = RMSNorm(args.dim, eps=args.norm_eps)
# output layer
self.output = ColumnParallelLinear(args.dim, args.vocab_size, bias=False, init_method=lambda x: x)
self.n_llama_layers = args.n_layers
self.model_dim = args.dim
# BLOCKS
self.fusion_schedule = self._init_fusion_schedule(args.vision_num_cross_attention_layers)
self.learnable_embedding = VocabParallelEmbedding(
max(fs_init.get_model_parallel_world_size(), 8),
args.dim,
init_method=lambda x: x,
)
self.num_frozen_embeddings = self.tok_embeddings.num_embeddings
self._thresh = self.num_frozen_embeddings - 1
# transformer blocks
self.layers = torch.nn.ModuleList()
self.cross_attention_layers = torch.nn.ModuleList()
for i in range(args.n_layers):
layer_id = i
block = TransformerBlock(args=args, layer_id=layer_id)
self.layers.append(block)
if layer_id in self.fusion_schedule:
xa_layer_id = self.fusion_schedule.index(layer_id) + args.n_layers
block = CrossAttentionTransformerBlock(
args,
layer_id=xa_layer_id,
)
self.cross_attention_layers.append(block)
# add xattn and dummy layers to avoid conditionals in forward()
self.text_and_xattn_layers = []
for idx, layer in enumerate(self.layers):
if idx in self.fusion_schedule:
xattn_layer_idx = self.fusion_schedule.index(idx)
xattn_layer = self.cross_attention_layers[xattn_layer_idx]
else:
xattn_layer_idx = 0
xattn_layer = DummyCrossAttentionTransformerBlock()
self.text_and_xattn_layers.append(
(
layer,
xattn_layer,
xattn_layer_idx,
)
)
self.freqs_cis = precompute_freqs_cis(
args.dim // args.n_heads,
args.max_seq_len * 2,
args.rope_theta,
args.use_scaled_rope,
)
self.args = args
self.cache_is_setup = False
self.max_seq_len = args.max_seq_len
def _init_fusion_schedule(
self,
num_layers: int,
) -> List[int]:
llama_layers = list(range(self.n_llama_layers))
# uniformly spread the layers
k = math.ceil(len(llama_layers) / num_layers)
return llama_layers[::-1][::k][:num_layers][::-1]
def get_partially_trainable_embedding(self, x):
xz = torch.zeros_like(x, device=x.device)
oz = torch.ones_like(x, device=x.device)
x_orig = torch.minimum(x, torch.tensor(self._thresh, device=x.device))
x_new = torch.maximum(x, torch.tensor(self._thresh + 1, device=x.device)) - self.num_frozen_embeddings
mask_orig = torch.where(x >= self.num_frozen_embeddings, xz, oz).unsqueeze(-1)
mask_new = torch.where(x < self.num_frozen_embeddings, xz, oz).unsqueeze(-1)
x_orig = self.tok_embeddings(x_orig)
x_new = self.learnable_embedding(x_new).type_as(x_orig)
return x_orig * mask_orig.type_as(x_orig) + x_new * mask_new.type_as(x_new)
def forward(
self,
position_ids: torch.LongTensor,
h: torch.Tensor,
xattn_mask: torch.Tensor,
full_text_row_masked_out_mask: torch.Tensor,
xattn_caches: torch.Tensor,
text_only_inference: bool = False,
):
assert self.cache_is_setup, "Please set up cache before calling forward"
mask = self.mask_cache.index_select(2, position_ids)
freqs_cis = self.freqs_cis.index_select(0, position_ids)
for (
layer,
xattn_layer,
xattn_layer_idx,
) in self.text_and_xattn_layers:
if not text_only_inference:
h = xattn_layer(
x=h,
xattn_mask=xattn_mask,
xattn_cache=xattn_caches[xattn_layer_idx],
full_text_row_masked_out_mask=full_text_row_masked_out_mask,
)
h = layer(
x=h,
mask=mask,
freqs_cis=freqs_cis,
position_ids=position_ids,
)
h = self.norm(h)
output = F.linear(h, self.output.weight)
output = gather_from_tensor_model_parallel_region(output)
return output.float()
def setup_cache(self, max_batch_size: int, dtype=torch.bfloat16):
# Set up the text kv caches
device = next(self.parameters()).device
ones = torch.ones(
(self.max_seq_len, self.max_seq_len),
dtype=torch.bool,
device=device,
)
self.register_buffer(
"mask_cache",
torch.tril(
ones,
)
.unsqueeze(0)
.unsqueeze(0),
persistent=False,
)
for layer in self.layers:
layer.setup_cache(max_batch_size, dtype=dtype)
self.cache_is_setup = True
def _get_xattn_mask(
self,
num_tokens,
text_device,
text_dtype,
vision_tokens,
cross_attention_masks,
) -> Tuple[Tensor, Tensor]:
assert vision_tokens is not None, "Vision tokens must be provided"
vision_seqlen = vision_tokens.shape[3]
assert vision_tokens.shape[1] == cross_attention_masks.shape[2], (
f"Mismatch in number of images given and number of masks given {vision_tokens.shape} {cross_attention_masks.shape}"
)
assert vision_tokens.shape[2] == cross_attention_masks.shape[3], (
f"Vision tokens shape {vision_tokens.shape} mismatch with xattn shape {cross_attention_masks.shape}"
)
assert num_tokens == cross_attention_masks.shape[1], (
f"Mismatch in text sequence length and cross attention mask sequence length {num_tokens} {cross_attention_masks.shape}"
)
_, _, _, num_image_tokens, image_token_dim = tuple(vision_tokens.shape)
bsz, ntext, nimg, nchunks = cross_attention_masks.shape
cross_attention_masks = (
cross_attention_masks.repeat_interleave(vision_seqlen, dim=3).view(bsz, ntext, -1).unsqueeze(1)
)
full_text_row_masked_out_mask = _get_full_row_masked_out_mask(
cross_attention_masks,
get_negative_inf_value(cross_attention_masks.dtype),
)
cross_attention_masks *= full_text_row_masked_out_mask
return (
cross_attention_masks.to(device=text_device, dtype=text_dtype),
full_text_row_masked_out_mask,
)
class CrossAttentionTransformer(torch.nn.Module):
def __init__(self, args: ModelArgs) -> None:
super().__init__()
self.params = args
self.model_dim = args.dim
self.vision_model = CrossAttentionTransformerVision(args)
self.text_model = CrossAttentionTransformerText(args)
self.image_res = args.vision_chunk_size
self.max_num_chunks = args.vision_max_num_chunks
self.image_transform = partial(
VariableSizeImageTransform(size=args.vision_chunk_size),
max_num_chunks=args.vision_max_num_chunks,
)
def setup_cache(self, max_batch_size: int, dtype: torch.dtype):
self.text_model.setup_cache(max_batch_size, dtype)
def compute_vision_tokens_masks(
self,
batch_images: List[List[PIL_Image.Image]],
batch_masks: List[List[List[int]]],
total_len: int,
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
skip_vision_encoder = False
assert len(batch_images) == len(batch_masks), "Images and masks must have the same length"
max_num_images = max(len(x) for x in batch_images)
bsz = len(batch_images)
if max_num_images == 0:
num_chunks = [[self.max_num_chunks] for _ in batch_images]
skip_vision_encoder = True
else:
images_and_aspect_ratios = [[self.image_transform(im) for im in row] for row in batch_images]
transformed_images = [[x[0] for x in row] for row in images_and_aspect_ratios]
aspect_ratios = torch.ones(bsz, max_num_images, 2, dtype=torch.int64)
for i, row in enumerate(images_and_aspect_ratios):
if len(row) > 0:
aspect_ratios[i, : len(row)] = torch.stack([torch.tensor(x[1]) for x in row])
stacked_images, num_chunks = _stack_images(
transformed_images,
max_num_chunks=self.max_num_chunks,
image_res=self.params.vision_chunk_size,
max_num_images=max_num_images,
)
if skip_vision_encoder:
vision_tokens = torch.zeros(
(
bsz,
max_num_images,
self.max_num_chunks,
int((self.vision_model.image_res / self.vision_model.patch_size) ** 2 + 1),
self.model_dim,
),
)
else:
vision_tokens = self.vision_model(stacked_images, aspect_ratios)
bsz, nimg, nchunk, ntok, image_token_dim = tuple(vision_tokens.shape)
xattn_caches = torch.stack(
[
layer.compute_xattn_kv_cache(vision_tokens.view(bsz, -1, image_token_dim))
for layer in self.text_model.cross_attention_layers
]
)
padded_masks = _pad_masks(
batch_masks,
num_chunks,
total_len,
self.max_num_chunks,
)
cross_attention_masks, full_text_row_masked_out_mask = self.text_model._get_xattn_mask(
num_tokens=total_len,
text_device=vision_tokens.device.type,
text_dtype=next(self.text_model.parameters()).dtype,
vision_tokens=vision_tokens,
cross_attention_masks=padded_masks,
)
return (xattn_caches, cross_attention_masks, full_text_row_masked_out_mask)
def forward(
self,
position_ids: torch.Tensor,
tokens: torch.Tensor,
cross_attention_masks: torch.Tensor,
full_text_row_masked_out_mask: torch.Tensor,
xattn_caches: torch.Tensor,
text_only_inference: bool = False,
) -> torch.Tensor:
h = self.text_model.get_partially_trainable_embedding(tokens[:, position_ids])
logits = self.text_model.forward(
position_ids=position_ids,
h=h,
xattn_mask=cross_attention_masks[:, :, position_ids],
full_text_row_masked_out_mask=full_text_row_masked_out_mask[:, :, position_ids],
xattn_caches=xattn_caches,
text_only_inference=text_only_inference,
)
return logits
def _stack_images(
images: List[List[PIL_Image.Image]],
max_num_chunks: int,
image_res: int,
max_num_images: int,
) -> Tuple[torch.Tensor, List[int]]:
"""
Takes a list of list of images and stacks them into a tensor.
This function is needed since images can be of completely
different resolutions and aspect ratios.
"""
out_images, out_num_chunks = [], []
for imgs_sample in images:
out_images_i = torch.zeros(
max_num_images,
max_num_chunks,
3,
image_res,
image_res,
)
_num_chunks = []
for j, chunks_image in enumerate(imgs_sample):
out_images_i[j, : chunks_image.shape[0]] = chunks_image
_num_chunks.append(chunks_image.shape[0])
out_images.append(out_images_i)
out_num_chunks.append(_num_chunks)
return torch.stack(out_images), out_num_chunks
def _pad_masks(
all_masks: List[List[List[int]]],
all_num_chunks: List[List[int]],
total_len: int,
max_num_chunks: int,
) -> torch.Tensor:
dtype = torch.get_default_dtype()
inf_value = get_negative_inf_value(dtype)
bsz = len(all_masks)
max_num_media = max([len(m) for m in all_masks])
out_masks = torch.full(
(bsz, total_len, max_num_media, max_num_chunks),
inf_value,
dtype=dtype,
)
for idx, (mask, num_chunks) in enumerate(zip(all_masks, all_num_chunks, strict=False)):
for mask_idx, (mask_elem, mask_num_chunks) in enumerate(zip(mask, num_chunks, strict=False)):
if len(mask_elem) == 2:
mask_elem[1] = min(mask_elem[1], total_len)
if mask_elem[1] == -1:
mask_elem[1] = total_len
out_masks[idx, mask_elem[0] : mask_elem[1], mask_idx, :mask_num_chunks].fill_(0.0)
return out_masks