LLaMA-Adapter / llama /model.py
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# Copyright (c) Meta Platforms, Inc. and affiliates.
# This software may be used and distributed according to the terms of the GNU General Public License version 3.
from typing import Optional, Tuple
from dataclasses import dataclass
import math
import torch
from torch import nn
import torch.nn.functional as F
import clip
from timm.models.vision_transformer import Block
import fairscale.nn.model_parallel.initialize as fs_init
from fairscale.nn.model_parallel.layers import (
ParallelEmbedding,
RowParallelLinear,
ColumnParallelLinear,
)
@dataclass
class ModelArgs:
dim: int = 512
n_layers: int = 8
n_heads: int = 8
vocab_size: int = -1 # defined later by tokenizer
multiple_of: int = 256 # make SwiGLU hidden layer size multiple of large power of 2
norm_eps: float = 1e-5
max_batch_size: int = 32
max_seq_len: int = 2048
adapter_len: int = 10
adapter_layer: int = 30
cap_adapter_len: int = 10
cap_adapter_layer: int = 30
cap_vision_model: str = "ViT-L/14"
cap_vision_dim: int = 512
cap_vision_block: int = 2
class RMSNorm(torch.nn.Module):
def __init__(self, dim: int, eps: float = 1e-6):
super().__init__()
self.eps = eps
self.weight = nn.Parameter(torch.ones(dim))
def _norm(self, x):
return x * torch.rsqrt(x.pow(2).mean(-1, keepdim=True) + self.eps)
def forward(self, x):
output = self._norm(x.float()).type_as(x)
return output * self.weight
def precompute_freqs_cis(dim: int, end: int, theta: float = 10000.0):
freqs = 1.0 / (theta ** (torch.arange(0, dim, 2)[: (dim // 2)].float() / dim))
t = torch.arange(end, device=freqs.device) # type: ignore
freqs = torch.outer(t, freqs).float() # type: ignore
freqs_cis = torch.polar(torch.ones_like(freqs), freqs) # complex64
return freqs_cis
def reshape_for_broadcast(freqs_cis: torch.Tensor, x: torch.Tensor):
ndim = x.ndim
assert 0 <= 1 < ndim
assert freqs_cis.shape == (x.shape[1], x.shape[-1])
shape = [d if i == 1 or i == ndim - 1 else 1 for i, d in enumerate(x.shape)]
return freqs_cis.view(*shape)
def apply_rotary_emb(
xq: torch.Tensor,
xk: torch.Tensor,
freqs_cis: torch.Tensor,
) -> Tuple[torch.Tensor, torch.Tensor]:
xq_ = torch.view_as_complex(xq.float().reshape(*xq.shape[:-1], -1, 2))
xk_ = torch.view_as_complex(xk.float().reshape(*xk.shape[:-1], -1, 2))
freqs_cis = reshape_for_broadcast(freqs_cis, xq_)
xq_out = torch.view_as_real(xq_ * freqs_cis).flatten(3)
xk_out = torch.view_as_real(xk_ * freqs_cis).flatten(3)
return xq_out.type_as(xq), xk_out.type_as(xk)
class Attention(nn.Module):
def __init__(self, args: ModelArgs):
super().__init__()
self.n_local_heads = args.n_heads // fs_init.get_model_parallel_world_size()
self.head_dim = args.dim // args.n_heads
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,
args.n_heads * self.head_dim,
bias=False,
gather_output=False,
init_method=lambda x: x,
)
self.wv = ColumnParallelLinear(
args.dim,
args.n_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.cache_k = torch.zeros(
(args.max_batch_size, args.max_seq_len, self.n_local_heads, self.head_dim)
).cuda()
self.cache_v = torch.zeros(
(args.max_batch_size, args.max_seq_len, self.n_local_heads, self.head_dim)
).cuda()
self.gate = torch.nn.Parameter(torch.zeros(1))
self.cap_gate = torch.nn.Parameter(torch.zeros(1, self.n_local_heads, 1, 1))
def forward(self, x: torch.Tensor, start_pos: int, freqs_cis: torch.Tensor, mask: Optional[torch.Tensor], adapter=None, mode='instruct'):
if mode == 'instruct':
return self.forward_instruct(x, start_pos, freqs_cis, mask, adapter)
elif mode == 'caption':
return self.forward_caption(x, start_pos, freqs_cis, mask, adapter)
def forward_instruct(self, x: torch.Tensor, start_pos: int, freqs_cis: torch.Tensor, mask: Optional[torch.Tensor], adapter=None):
bsz, seqlen, _ = x.shape
xq, xk, xv = self.wq(x), self.wk(x), self.wv(x)
xq = xq.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xk = xk.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xv = xv.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xq, xk = apply_rotary_emb(xq, xk, freqs_cis=freqs_cis)
self.cache_k = self.cache_k.to(xq)
self.cache_v = self.cache_v.to(xq)
self.cache_k[:bsz, start_pos : start_pos + seqlen] = xk
self.cache_v[:bsz, start_pos : start_pos + seqlen] = xv
keys = self.cache_k[:bsz, : start_pos + seqlen]
values = self.cache_v[:bsz, : start_pos + seqlen]
if adapter is not None:
adapter_len = adapter.shape[1]
adapter_k = self.wk(adapter).view(1, adapter_len, self.n_local_heads, self.head_dim).repeat(bsz, 1, 1, 1)
adapter_v = self.wv(adapter).view(1, adapter_len, self.n_local_heads, self.head_dim).repeat(bsz, 1, 1, 1)
adapter_k = adapter_k.transpose(1, 2)
adapter_v = adapter_v.transpose(1, 2)
xq = xq.transpose(1, 2)
keys = keys.transpose(1, 2)
values = values.transpose(1, 2)
scores = torch.matmul(xq, keys.transpose(2, 3)) / math.sqrt(self.head_dim)
if mask is not None:
scores = scores + mask # (bs, n_local_heads, slen, cache_len + slen)
scores = F.softmax(scores.float(), dim=-1).type_as(xq)
output = torch.matmul(scores, values) # (bs, n_local_heads, slen, head_dim)
if adapter is not None:
adapter_scores = torch.matmul(xq, adapter_k.transpose(2, 3)) / math.sqrt(self.head_dim)
adapter_scores = self.gate * F.softmax(adapter_scores.float(), dim=-1).type_as(xq)
output = output + torch.matmul(adapter_scores, adapter_v)
output = output.transpose(
1, 2
).contiguous().view(bsz, seqlen, -1)
return self.wo(output)
def forward_caption(self, x: torch.Tensor, start_pos: int, freqs_cis: torch.Tensor, mask: Optional[torch.Tensor], adapter=None):
bsz, seqlen, _ = x.shape
xq, xk, xv = self.wq(x), self.wk(x), self.wv(x)
xq = xq.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xk = xk.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xv = xv.view(bsz, seqlen, self.n_local_heads, self.head_dim)
xq, xk = apply_rotary_emb(xq, xk, freqs_cis=freqs_cis)
self.cache_k = self.cache_k.to(xq)
self.cache_v = self.cache_v.to(xq)
self.cache_k[:bsz, start_pos : start_pos + seqlen] = xk
self.cache_v[:bsz, start_pos : start_pos + seqlen] = xv
keys = self.cache_k[:bsz, : start_pos + seqlen]
values = self.cache_v[:bsz, : start_pos + seqlen]
if adapter is not None:
adapter_len = adapter.shape[1]
adapter_k = self.wk(adapter).view(bsz, adapter_len, self.n_local_heads, self.head_dim)
adapter_v = self.wv(adapter).view(bsz, adapter_len, self.n_local_heads, self.head_dim)
adapter_k = adapter_k.transpose(1, 2)
adapter_v = adapter_v.transpose(1, 2)
xq = xq.transpose(1, 2)
keys = keys.transpose(1, 2)
values = values.transpose(1, 2)
scores = torch.matmul(xq, keys.transpose(2, 3)) / math.sqrt(self.head_dim)
if mask is not None:
scores = scores + mask # (bs, n_local_heads, slen, cache_len + slen)
scores = F.softmax(scores.float(), dim=-1).type_as(xq)
output = torch.matmul(scores, values) # (bs, n_local_heads, slen, head_dim)
if adapter is not None:
adapter_scores = torch.matmul(xq, adapter_k.transpose(2, 3)) / math.sqrt(self.head_dim)
adapter_scores = self.cap_gate.tanh() * F.softmax(adapter_scores.float(), dim=-1).type_as(xq)
output = output + torch.matmul(adapter_scores, adapter_v)
output = output.transpose(
1, 2
).contiguous().view(bsz, seqlen, -1)
return self.wo(output)
class FeedForward(nn.Module):
def __init__(
self,
dim: int,
hidden_dim: int,
multiple_of: int,
):
super().__init__()
hidden_dim = int(2 * hidden_dim / 3)
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):
return self.w2(F.silu(self.w1(x)) * self.w3(x))
class TransformerBlock(nn.Module):
def __init__(self, layer_id: int, args: ModelArgs):
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
)
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 forward(self, x: torch.Tensor, start_pos: int, freqs_cis: torch.Tensor, mask: Optional[torch.Tensor], adapter=None, mode='instruct'):
h = x + self.attention.forward(self.attention_norm(x), start_pos, freqs_cis, mask, adapter, mode=mode)
out = h + self.feed_forward.forward(self.ffn_norm(h))
return out
class Transformer(nn.Module):
def __init__(self, params: ModelArgs):
super().__init__()
self.params = params
self.vocab_size = params.vocab_size
self.n_layers = params.n_layers
self.tok_embeddings = ParallelEmbedding(
params.vocab_size, params.dim, init_method=lambda x: x
)
self.layers = torch.nn.ModuleList()
for layer_id in range(params.n_layers):
self.layers.append(TransformerBlock(layer_id, params))
self.norm = RMSNorm(params.dim, eps=params.norm_eps)
self.output = ColumnParallelLinear(
params.dim, params.vocab_size, bias=False, init_method=lambda x: x
)
self.freqs_cis = precompute_freqs_cis(
self.params.dim // self.params.n_heads, self.params.max_seq_len * 2
)
# Note: this is only a preview of multimodal LLaMA-Adapter
# and requires more efforts to decouple LLaMA-Adapter from LLaMA.
# instruct model
self.adapter_query = nn.Embedding(params.adapter_len * params.adapter_layer, params.dim)
self.adapter_len = params.adapter_len
self.adapter_layer = params.adapter_layer
# caption model
self.cap_adapter_query = nn.Embedding(params.cap_adapter_len * params.cap_adapter_layer, params.dim)
self.cap_adapter_len = params.cap_adapter_len
self.cap_adapter_layer = params.cap_adapter_layer
@torch.inference_mode()
def forward(self, tokens: torch.Tensor, start_pos: int, visual_tokens: torch.Tensor = None, mode: str = 'instruct'):
if mode == 'instruct':
return self.forward_instruct(tokens, start_pos, mode)
elif mode == 'caption':
return self.forward_caption(tokens, start_pos, visual_tokens, mode)
def forward_instruct(self, tokens: torch.Tensor, start_pos: int, mode=None):
_bsz, seqlen = tokens.shape
h = self.tok_embeddings(tokens)
self.freqs_cis = self.freqs_cis.to(h.device)
freqs_cis = self.freqs_cis[start_pos : start_pos + seqlen]
adapter = self.adapter_query.weight.reshape(self.params.adapter_layer, self.params.adapter_len, self.params.dim).unsqueeze(1)
mask = None
if seqlen > 1:
mask = torch.full((1, 1, seqlen, seqlen), float("-inf"), device=tokens.device)
mask = torch.triu(mask, diagonal=start_pos + 1).type_as(h)
for layer in self.layers[: -1 * self.params.adapter_layer]:
h = layer(h, start_pos, freqs_cis, mask)
layer_index = 0
for layer in self.layers[-1 * self.params.adapter_layer:]:
h = layer(h, start_pos, freqs_cis, mask, adapter[layer_index], mode=mode)
layer_index = layer_index + 1
h = self.norm(h)
output = self.output(h[:, -1, :]) # only compute last logits
return output.float()
def forward_caption(self, tokens: torch.Tensor, start_pos: int, visual_tokens: torch.Tensor = None, mode=None):
_bsz, seqlen = tokens.shape
h = self.tok_embeddings(tokens)
self.freqs_cis = self.freqs_cis.to(h.device)
freqs_cis = self.freqs_cis[start_pos : start_pos + seqlen]
adapter = self.cap_adapter_query.weight.reshape(self.params.cap_adapter_layer, self.params.cap_adapter_len, self.params.dim).unsqueeze(1)
mask = None
if seqlen > 1:
mask = torch.full((1, 1, seqlen, seqlen), float("-inf"), device=tokens.device)
mask = torch.triu(mask, diagonal=start_pos + 1).type_as(h)
for layer in self.layers[: -1 * self.params.cap_adapter_layer]:
h = layer(h, start_pos, freqs_cis, mask)
layer_index = 0
for layer in self.layers[-1 * self.params.cap_adapter_layer:]:
adapter_per_layer = adapter[layer_index]
if visual_tokens is not None:
adapter_per_layer = adapter_per_layer + visual_tokens
h = layer(h, start_pos, freqs_cis, mask, adapter_per_layer, mode=mode)
layer_index = layer_index + 1
h = self.norm(h)
output = self.output(h[:, -1, :]) # only compute last logits
return output.float()
class VisionModel(nn.Module):
def __init__(self, params: ModelArgs):
super().__init__()
self.params = params
self.clip, self.clip_transform = clip.load(params.cap_vision_model)
self.clip.float()
for param in self.clip.parameters():
param.requires_grad = False
self.clip_proj = nn.Linear(self.clip.visual.output_dim, params.cap_vision_dim)
self.clip_proj_norm = nn.LayerNorm(params.cap_vision_dim)
self.visual_query = nn.Embedding(params.cap_adapter_len, params.cap_vision_dim)
self.visual_blocks = nn.ModuleList([
Block(params.cap_vision_dim, 16, 4, qkv_bias=True, qk_scale=None, norm_layer=nn.LayerNorm)
for i in range(params.cap_vision_block)])
self.visual_proj = nn.Linear(params.cap_vision_dim, params.dim)
self.visual_proj_norm = nn.LayerNorm(params.dim)
def clip_encode_image(self, x):
x = self.clip.visual.conv1(x) # shape = [*, width, grid, grid]
x = x.reshape(x.shape[0], x.shape[1], -1) # shape = [*, width, grid ** 2]
x = x.permute(0, 2, 1) # shape = [*, grid ** 2, width]
x = torch.cat([self.clip.visual.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]
x = x + self.clip.visual.positional_embedding.to(x.dtype)
x = self.clip.visual.ln_pre(x)
x = x.permute(1, 0, 2) # NLD -> LND
x = self.clip.visual.transformer(x)
x = x.permute(1, 0, 2) # LND -> NLD
x = self.clip.visual.ln_post(x[:, :, :])
if self.clip.visual.proj is not None:
x = x @ self.clip.visual.proj
return x
def forward(self, imgs):
x = [self.clip_transform(img) for img in imgs]
x = torch.stack(x, dim=0).to(self.visual_query.weight.device)
_bsz = x.shape[0]
visual_feats = self.clip_encode_image(x).half()
visual_feats = self.clip_proj_norm(self.clip_proj(visual_feats))
visual_query = self.visual_query.weight.unsqueeze(0).repeat(_bsz, 1, 1)
visual_query = torch.cat([visual_query, visual_feats], dim=1)
for block in self.visual_blocks:
visual_query = block(visual_query)
visual_query = visual_query[:, :self.params.cap_adapter_len, :]
visual_query = self.visual_proj(visual_query)
visual_query = self.visual_proj_norm(visual_query)
return visual_query