esper / clipcap.py
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import os
import math
import logging
import json
from pathlib import Path
from typing import Tuple, Optional, Union
import torch
import torch.nn as nn
from torch.nn import functional as F
from transformers import AutoModelForCausalLM, AutoTokenizer, GPTJForCausalLM
logging.basicConfig(level=os.environ.get("LOGLEVEL", "INFO"))
log = logging.getLogger(__name__)
def load_weights(self, Module, path, name, default_name, prev_name=None, **kwargs):
hparams = None
assert isinstance(default_name, str), f'invalid default transformer name: {default_name}'
model = get_transformer_module(Module, default_name, **kwargs)
setattr(self, name, model)
return hparams
def get_transformer_module(Module, default_name, **kwargs):
if default_name == 'EleutherAI/gpt-j-6B':
kwargs = {**kwargs, **dict(revision="float16", torch_dtype=torch.float16, low_cpu_mem_usage=True)}
model = Module.from_pretrained(default_name, **kwargs)
return model
class MLP(nn.Module):
def __init__(self, sizes: Tuple[int, ...], bias=True, act=nn.Tanh):
super(MLP, self).__init__()
self.divider = math.sqrt(sizes[-1] / sizes[0])
layers = []
for i in range(len(sizes) - 1):
layers.append(nn.Linear(sizes[i], sizes[i + 1], bias=bias))
if i < len(sizes) - 2:
layers.append(act())
self.model = nn.Sequential(*layers)
def forward(self, x: torch.Tensor) -> torch.Tensor:
x = x / self.divider # scaling for the initial stability
x = self.model(x)
return x
class MlpTransformer(nn.Module):
def __init__(self, in_dim, h_dim, out_d: Optional[int] = None, act=F.relu, dropout=0.):
super().__init__()
out_d = out_d if out_d is not None else in_dim
self.fc1 = nn.Linear(in_dim, h_dim)
self.act = act
self.fc2 = nn.Linear(h_dim, out_d)
self.dropout = nn.Dropout(dropout)
def forward(self, x):
x = self.fc1(x)
x = self.act(x)
x = self.dropout(x)
x = self.fc2(x)
x = self.dropout(x)
return x
class MultiHeadAttention(nn.Module):
def __init__(self, dim_self, dim_ref, num_heads, bias=True, dropout=0.):
super().__init__()
self.num_heads = num_heads
head_dim = dim_self // num_heads
self.scale = head_dim ** -0.5
self.to_queries = nn.Linear(dim_self, dim_self, bias=bias)
self.to_keys_values = nn.Linear(dim_ref, dim_self * 2, bias=bias)
self.project = nn.Linear(dim_self, dim_self)
self.dropout = nn.Dropout(dropout)
def forward(self, x, y=None, mask=None):
y = y if y is not None else x
b, n, c = x.shape
_, m, d = y.shape
# b n h dh
queries = self.to_queries(x).reshape(b, n, self.num_heads, c // self.num_heads)
# b m 2 h dh
keys_values = self.to_keys_values(y).reshape(b, m, 2, self.num_heads, c // self.num_heads)
keys, values = keys_values[:, :, 0], keys_values[:, :, 1]
attention = torch.einsum('bnhd,bmhd->bnmh', queries, keys) * self.scale
if mask is not None:
if mask.dim() == 2:
mask = mask.unsqueeze(1)
attention = attention.masked_fill(mask.unsqueeze(3), float("-inf"))
attention = attention.softmax(dim=2)
out = torch.einsum('bnmh,bmhd->bnhd', attention, values).reshape(b, n, c)
out = self.project(out)
return out, attention
class TransformerLayer(nn.Module):
def __init__(self, dim_self, dim_ref, num_heads, mlp_ratio=4., bias=False, dropout=0., act=F.relu,
norm_layer: nn.Module = nn.LayerNorm):
super().__init__()
self.norm1 = norm_layer(dim_self)
self.attn = MultiHeadAttention(dim_self, dim_ref, num_heads, bias=bias, dropout=dropout)
self.norm2 = norm_layer(dim_self)
self.mlp = MlpTransformer(dim_self, int(dim_self * mlp_ratio), act=act, dropout=dropout)
def forward_with_attention(self, x, y=None, mask=None):
x_, attention = self.attn(self.norm1(x), y, mask)
x = x + x_
x = x + self.mlp(self.norm2(x))
return x, attention
def forward(self, x, y=None, mask=None):
x = x + self.attn(self.norm1(x), y, mask)[0]
x = x + self.mlp(self.norm2(x))
return x
class Transformer(nn.Module):
def forward_with_attention(self, x, y=None, mask=None):
attentions = []
for layer in self.layers:
x, att = layer.forward_with_attention(x, y, mask)
attentions.append(att)
return x, attentions
def forward(self, x, y=None, mask=None):
for i, layer in enumerate(self.layers):
if i % 2 == 0 and self.enc_dec: # cross
x = layer(x, y)
elif self.enc_dec: # self
x = layer(x, x, mask)
else: # self or cross
x = layer(x, y, mask)
return x
def __init__(self, dim_self: int, num_heads: int, num_layers: int, dim_ref: Optional[int] = None,
mlp_ratio: float = 2., act=F.relu, norm_layer: nn.Module = nn.LayerNorm, enc_dec: bool = False):
super(Transformer, self).__init__()
dim_ref = dim_ref if dim_ref is not None else dim_self
self.enc_dec = enc_dec
if enc_dec:
num_layers = num_layers * 2
layers = []
for i in range(num_layers):
if i % 2 == 0 and enc_dec: # cross
layers.append(TransformerLayer(dim_self, dim_ref, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
elif enc_dec: # self
layers.append(TransformerLayer(dim_self, dim_self, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
else: # self or cross
layers.append(TransformerLayer(dim_self, dim_ref, num_heads, mlp_ratio, act=act, norm_layer=norm_layer))
self.layers = nn.ModuleList(layers)
class TransformerMapper(nn.Module):
def __init__(self, dim_clip: int, dim_embedding: int, prefix_length: int = 10,
clip_length: int = 10, num_layers: int = 8):
super(TransformerMapper, self).__init__()
self.clip_length = clip_length
self.transformer = Transformer(dim_embedding, 8, num_layers)
self.linear = nn.Linear(dim_clip, clip_length * dim_embedding)
self.prefix_const = nn.Parameter(torch.randn(prefix_length, dim_embedding), requires_grad=True)
def forward(self, x):
x = self.linear(x).view(x.shape[0], self.clip_length, -1)
prefix = self.prefix_const.unsqueeze(0).expand(x.shape[0], *self.prefix_const.shape)
prefix = torch.cat((x, prefix), dim=1)
out = self.transformer(prefix)[:, self.clip_length:]
return out
class ClipCap(nn.Module):
def __init__(self, model_name, device, prefix_length: int = 10, clip_length: int = 40, prefix_size: int = 512,
num_layers: int = 1, model_path: str = '', fix_gpt: bool = False,
use_label_prefix: bool = False, label_path: str = '', label_length: int = 10,
use_transformer_mapper: bool = False, use_ptuning_v2: bool = False,
dropout: float = 0,
model_weight: str = '', scalar_output: bool = False):
super(ClipCap, self).__init__()
self.prefix_length = prefix_length
self.prefix_size = prefix_size
self.label_length = label_length
self.scalar_output = scalar_output
self.num_layers = num_layers
self.use_transformer_mapper = use_transformer_mapper
self.use_ptuning_v2 = use_ptuning_v2
self.dropout = nn.Dropout(dropout)
hparams = load_weights(self, AutoModelForCausalLM, model_weight, 'gpt', model_name,
prev_name='model')
self.device = device
self.gpt = self.gpt.to(self.device)
config = self.gpt.config
self.match_n_layer = getattr(config, 'n_layer', getattr(config, 'num_layers', None)) # gpt2 vs. gpt_neo
self.match_n_head = getattr(config, 'n_head', getattr(config, 'num_heads', None))
self.n_embd = getattr(config, 'n_embd', getattr(config, 'hidden_size', None))
self.match_n_embd = self.n_embd // self.match_n_head
self.clip_project = self.get_mapper()
if Path(label_path).is_file():
with open(label_path) as f:
labels = json.load(f)
self.labels = {i: v for v, i in labels.items()}
if not use_label_prefix:
log.info("adding label projections")
self.label_project = nn.Sequential(
nn.Embedding(len(self.labels), self.prefix_size),
self.get_mapper()
)
if os.path.isfile(model_path):
log.info(f"loading model from {model_path}")
weight = torch.load(model_path, map_location=torch.device('cpu'))
weight = {k[len('clip_project.'):]: v for k, v in weight.items()
if k.startswith('clip_project.')}
self.clip_project.load_state_dict(weight)
if fix_gpt:
log.info("fixing gpt parameters")
for param in self.gpt.parameters():
param.requires_grad_(False)
if self.scalar_output:
self.gpt.lm_head = nn.Linear(self.gpt.transformer.embed_dim, 1).to(self.device)
self.clip_project = self.clip_project.to(self.device)
if hasattr(self, 'label_project'):
self.label_project = self.label_project.to(self.device)
def get_mapper(self):
if self.use_ptuning_v2:
total_embd = self.match_n_layer * 2 * self.n_embd
module = MLP((self.prefix_size,
*[self.prefix_size
for i in range(self.num_layers)],
total_embd * self.prefix_length))
elif self.use_transformer_mapper:
log.info("using transformer mapper")
module = TransformerMapper(self.prefix_size, self.n_embd,
self.prefix_length, self.prefix_length, num_layers=self.num_layers) # 8)
else:
module = MLP((self.prefix_size,
*[(self.n_embd * self.prefix_length) // 2
for i in range(self.num_layers)],
self.n_embd * self.prefix_length))
return module
def get_encoder_loss(self, input_ids: torch.Tensor, features: torch.Tensor,
device = None):
input_ids = input_ids[:, :self.prefix_length].to(device)
embedding = self.gpt.transformer.wte(input_ids)
features = features.to(device)
prefix_projections = self.clip_project(features.type_as(embedding)).reshape(-1, self.prefix_length, self.n_embd)
fct = nn.MSELoss()
loss = fct(prefix_projections, embedding.detach())
return loss
def forward(self, *args, **kwargs):
if self.use_ptuning_v2:
return self.forward_prefix(*args, **kwargs)
else:
return self.forward_embedding(*args, **kwargs)
def forward_embedding(self, input_ids: torch.Tensor, features: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
labels: Optional[torch.Tensor] = None,
past_key_values = None, device = None, **kwargs):
if device is None:
device = self.device
input_ids = input_ids.to(device)
if features is not None:
features = features.to(device)
if attention_mask is not None:
attention_mask = attention_mask.to(device)
if labels is not None:
labels = labels.to(device)
use_labels = labels is not None and hasattr(self, 'label_project')
embedding = self.gpt.transformer.wte(input_ids)
embed_txt = embedding
prefix_length = self.prefix_length
if use_labels:
prefix_length += self.label_length
if past_key_values is None:
prefix_projections = self.clip_project(features.type_as(embedding)).reshape(-1, self.prefix_length, self.n_embd)
if use_labels:
label_projections = self.label_project(labels.long()).reshape(-1, self.label_length, self.n_embd)
prefix_projections = torch.cat((prefix_projections, label_projections), dim=1)
embedding = torch.cat((prefix_projections.to(embedding.dtype), embedding), dim=1)
if torch.is_tensor(attention_mask):
prefix_mask = torch.ones_like(attention_mask)[:, :1].repeat(1, prefix_length)
attention_mask = torch.cat([prefix_mask, attention_mask], dim=1)
outputs = self.gpt(inputs_embeds=embedding, attention_mask=attention_mask,
past_key_values=past_key_values,
return_dict=True,
output_attentions=False,
output_hidden_states=True)
if past_key_values is None:
outputs.logits = outputs.logits[:, prefix_length:]
return outputs
def forward_prefix(self, input_ids: torch.Tensor, features: torch.Tensor,
attention_mask: Optional[torch.Tensor] = None,
labels: Optional[torch.Tensor] = None,
past_key_values = None, device = None, **kwargs):
if device is None:
device = self.device
input_ids = input_ids.to(device)
if features is not None:
features = features.to(device)
if attention_mask is not None:
attention_mask = attention_mask.to(device)
if labels is not None:
labels = labels.to(device)
use_labels = labels is not None and hasattr(self, 'label_project')
prefix_length = self.prefix_length
if use_labels:
prefix_length += self.label_length
if past_key_values is None:
prefix_projections = self.clip_project(features.type_as(self.clip_project.model[0].weight))
prefix_projections = prefix_projections.reshape(-1, self.prefix_length,
self.match_n_layer * 2, self.match_n_head, self.match_n_embd)
if use_labels:
label_projections = self.label_project(labels.long())
label_projections = label_projections.reshape(-1, self.label_length,
self.match_n_layer * 2, self.match_n_head, self.match_n_embd)
prefix_projections = torch.cat((prefix_projections, label_projections), dim=1)
temp_control = prefix_projections
temp_control = self.dropout(temp_control)
past_key_values = temp_control.permute([2, 0, 3, 1, 4]).split(2)
if torch.is_tensor(attention_mask):
prefix_mask = torch.ones_like(attention_mask)[:, :1].repeat(1, prefix_length)
attention_mask = torch.cat([prefix_mask, attention_mask], dim=1)
outputs = self.gpt(input_ids=input_ids, attention_mask=attention_mask,
past_key_values=past_key_values,
return_dict=True,
output_attentions=False,
output_hidden_states=True)
if past_key_values is None:
outputs.logits = outputs.logits[:, prefix_length:]
return outputs
def prepare_inputs_for_generation(self, input_ids, past=None, **kwargs):
token_type_ids = kwargs.get("token_type_ids", None)
# only last token for inputs_ids if past is defined in kwargs
if past:
input_ids = input_ids[:, -1].unsqueeze(-1)
if token_type_ids is not None:
token_type_ids = token_type_ids[:, -1].unsqueeze(-1)
attention_mask = kwargs.get("attention_mask", None)
position_ids = kwargs.get("position_ids", None)
features = kwargs.get("features", None)
labels = kwargs.get("labels", 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_(attention_mask == 0, 1)
if past:
position_ids = position_ids[:, -1].unsqueeze(-1)
else:
position_ids = None
return {
"input_ids": input_ids,
"past_key_values": past,
"use_cache": kwargs.get("use_cache"),
"position_ids": position_ids,
"attention_mask": attention_mask,
"token_type_ids": token_type_ids,
"features": features,
"labels": labels,
}