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"""
Copyright (c) 2022, salesforce.com, inc.
All rights reserved.
SPDX-License-Identifier: BSD-3-Clause
For full license text, see the LICENSE file in the repo root or https://opensource.org/licenses/BSD-3-Clause
"""
from copy import deepcopy
import torch
import torch.nn.functional as F
from lavis.common.registry import registry
from lavis.models.albef_models import AlbefBase, compute_sim_matrix
from lavis.models.albef_models.albef_outputs import (
AlbefIntermediateOutput,
AlbefOutput,
AlbefSimilarity,
)
from lavis.models.base_model import MomentumDistilationMixin, SharedQueueMixin
from lavis.models.med import XBertEncoder
from lavis.models.vit import VisionTransformerEncoder
from torch import nn
@registry.register_model("albef_retrieval")
class AlbefRetrieval(AlbefBase, MomentumDistilationMixin, SharedQueueMixin):
"""
ALBEF retrieval model.
Supported model types:
- coco: fine-tuned ALBEF base model on COCO dataset (Karparthy split).
- flickr: fine-tuned ALBEF base model on Flickr30k dataset.
Usage:
>>> from lavis.models import load_model
>>> model = load_model("albef_retrieval", "coco")
>>> model = load_model("albef_retrieval", "flickr")
"""
PRETRAINED_MODEL_CONFIG_DICT = {
"coco": "configs/models/albef_retrieval_coco.yaml",
"flickr": "configs/models/albef_retrieval_flickr.yaml",
}
def __init__(
self,
image_encoder,
text_encoder,
queue_size,
embed_dim=256,
temp=0.07,
use_distill=True,
momentum=0.995,
alpha=0.4,
max_txt_len=30,
):
super().__init__()
self.tokenizer = self.init_tokenizer()
self.visual_encoder = image_encoder
self.text_encoder = text_encoder
text_width = text_encoder.config.hidden_size
vision_width = image_encoder.vision_width
self.vision_proj = nn.Linear(vision_width, embed_dim)
self.text_proj = nn.Linear(text_width, embed_dim)
self.itm_head = nn.Linear(text_width, 2)
# create the momentum encoder
self.visual_encoder_m = deepcopy(self.visual_encoder)
self.text_encoder_m = deepcopy(self.text_encoder)
self.vision_proj_m = deepcopy(self.vision_proj)
self.text_proj_m = deepcopy(self.text_proj)
self.model_pairs = [
[self.visual_encoder, self.visual_encoder_m],
[self.text_encoder, self.text_encoder_m],
[self.vision_proj, self.vision_proj_m],
[self.text_proj, self.text_proj_m],
]
self.copy_params()
# create the queue
self.register_buffer("image_queue", torch.randn(embed_dim, queue_size))
self.register_buffer("text_queue", torch.randn(embed_dim, queue_size))
self.register_buffer("idx_queue", torch.full((1, queue_size), -100))
self.register_buffer("queue_ptr", torch.zeros(1, dtype=torch.long))
self.image_queue = nn.functional.normalize(self.image_queue, dim=0)
self.text_queue = nn.functional.normalize(self.text_queue, dim=0)
self.queue_size = queue_size
self.momentum = momentum
self.temp = nn.Parameter(temp * torch.ones([]))
self.alpha = alpha
self.max_txt_len = max_txt_len
self.use_distill = use_distill
def _rampup_factor(self, epoch, iters, num_iters_per_epoch):
return min(1, (epoch * num_iters_per_epoch + iters) / (2 * num_iters_per_epoch))
def forward(self, samples):
"""
Args:
samples (dict): A dictionary containing the following keys:
- image (torch.Tensor): A tensor of shape (batch_size, 3, H, W). The input images.
- text_input (list): A list of length batch_size, each element is a string of text/caption.
- image_id (torch.Tensor): A tensor of shape (batch_size, ). The image ids, used to identify same images in batch.
- epoch (int): The current epoch.
- iters (int): The current iteration.
- num_iters_per_epoch (int): The number of iterations per epoch.
Returns:
BlipOutput: A BlipOutput object. See ``lavis.models.blip_models.blip_outputs.BlipOutput`` for more details.
Examples:
>>> import torch
>>> from lavis.models import load_model
>>> model = load_model("albef_retrieval", "coco")
>>> images = torch.randn(4, 3, 384, 384)
>>> text_input = ["caption of image 1", "another caption of image 1", "caption of image 2", "caption of image 3"]
>>> image_id = torch.tensor([1, 1, 2, 3])
>>> samples = {"image": images, "text_input": text_input, "image_id": image_id, "epoch": 0, "iters": 0, "num_iters_per_epoch": 100}
>>> output = model(samples)
>>> output.keys()
odict_keys(['sims', 'intermediate_output', 'loss', 'loss_itc', 'loss_itm'])
"""
image = samples["image"]
caption = samples["text_input"]
idx = samples["image_id"]
alpha = self.alpha * self._rampup_factor(
epoch=samples["epoch"],
iters=samples["iters"],
num_iters_per_epoch=samples["num_iters_per_epoch"],
)
with torch.no_grad():
self.temp.clamp_(0.001, 0.5)
image_embeds = self.visual_encoder.forward_features(image)
image_atts = torch.ones(image_embeds.size()[:-1], dtype=torch.long).to(
self.device
)
image_feat = F.normalize(self.vision_proj(image_embeds[:, 0, :]), dim=-1)
text = self.tokenizer(
caption,
padding="max_length",
truncation=True,
max_length=self.max_txt_len,
return_tensors="pt",
).to(self.device)
text_output = self.text_encoder.forward_text(text)
text_embeds = text_output.last_hidden_state
text_feat = F.normalize(self.text_proj(text_embeds[:, 0, :]), dim=-1)
idx = idx.view(-1, 1)
idx_all = torch.cat([idx.t(), self.idx_queue.clone().detach()], dim=1)
pos_idx = torch.eq(idx, idx_all).float()
sim_targets = pos_idx / pos_idx.sum(1, keepdim=True)
with torch.no_grad():
self._momentum_update()
image_embeds_m = self.visual_encoder_m(image)
image_feat_m = F.normalize(
self.vision_proj_m(image_embeds_m[:, 0, :]), dim=-1
)
image_feat_all = torch.cat(
[image_feat_m.t(), self.image_queue.clone().detach()], dim=1
)
text_output_m = self.text_encoder_m.forward_text(text)
text_embeds_m = text_output_m.last_hidden_state
text_feat_m = F.normalize(self.text_proj_m(text_embeds_m[:, 0, :]), dim=-1)
text_feat_all = torch.cat(
[text_feat_m.t(), self.text_queue.clone().detach()], dim=1
)
if self.use_distill:
sim_i2t_m = image_feat_m @ text_feat_all / self.temp
sim_t2i_m = text_feat_m @ image_feat_all / self.temp
sim_i2t_targets = (
alpha * F.softmax(sim_i2t_m, dim=1) + (1 - alpha) * sim_targets
)
sim_t2i_targets = (
alpha * F.softmax(sim_t2i_m, dim=1) + (1 - alpha) * sim_targets
)
sim_i2t = image_feat @ text_feat_all / self.temp
sim_t2i = text_feat @ image_feat_all / self.temp
if self.use_distill:
loss_i2t = -torch.sum(
F.log_softmax(sim_i2t, dim=1) * sim_i2t_targets, dim=1
).mean()
loss_t2i = -torch.sum(
F.log_softmax(sim_t2i, dim=1) * sim_t2i_targets, dim=1
).mean()
else:
loss_i2t = -torch.sum(
F.log_softmax(sim_i2t, dim=1) * sim_targets, dim=1
).mean()
loss_t2i = -torch.sum(
F.log_softmax(sim_t2i, dim=1) * sim_targets, dim=1
).mean()
loss_itc = (loss_i2t + loss_t2i) / 2
self._dequeue_and_enqueue(image_feat_m, text_feat_m, idx)
encoder_output_pos = self.text_encoder(
encoder_embeds=text_embeds,
attention_mask=text.attention_mask,
encoder_hidden_states=image_embeds,
encoder_attention_mask=image_atts,
return_dict=True,
mode="fusion",
)
with torch.no_grad():
bs = image.size(0)
weights_i2t = F.softmax(sim_i2t[:, :bs] + 1e-4, dim=1)
weights_t2i = F.softmax(sim_t2i[:, :bs] + 1e-4, dim=1)
mask = torch.eq(idx, idx.T)
weights_i2t.masked_fill_(mask, 0)
weights_t2i.masked_fill_(mask, 0)
# select a negative image for each text
image_embeds_neg = []
for b in range(bs):
neg_idx = torch.multinomial(weights_t2i[b], 1).item()
image_embeds_neg.append(image_embeds[neg_idx])
image_embeds_neg = torch.stack(image_embeds_neg, dim=0)
# select a negative text for each image
text_embeds_neg = []
text_atts_neg = []
for b in range(bs):
neg_idx = torch.multinomial(weights_i2t[b], 1).item()
text_embeds_neg.append(text_embeds[neg_idx])
text_atts_neg.append(text.attention_mask[neg_idx])
text_embeds_neg = torch.stack(text_embeds_neg, dim=0)
text_atts_neg = torch.stack(text_atts_neg, dim=0)
text_embeds_all = torch.cat([text_embeds, text_embeds_neg], dim=0)
text_atts_all = torch.cat([text.attention_mask, text_atts_neg], dim=0)
image_embeds_all = torch.cat([image_embeds_neg, image_embeds], dim=0)
image_atts_all = torch.cat([image_atts, image_atts], dim=0)
encoder_output_neg = self.text_encoder(
encoder_embeds=text_embeds_all,
attention_mask=text_atts_all,
encoder_hidden_states=image_embeds_all,
encoder_attention_mask=image_atts_all,
return_dict=True,
mode="fusion",
)
vl_embeddings = torch.cat(
[
encoder_output_pos.last_hidden_state[:, 0, :],
encoder_output_neg.last_hidden_state[:, 0, :],
],
dim=0,
)
itm_logits = self.itm_head(vl_embeddings)
itm_labels = torch.cat(
[torch.ones(bs, dtype=torch.long), torch.zeros(2 * bs, dtype=torch.long)],
dim=0,
).to(self.device)
loss_itm = F.cross_entropy(itm_logits, itm_labels)
return AlbefOutput(
loss=loss_itc + loss_itm,
loss_itc=loss_itc,
loss_itm=loss_itm,
sims=AlbefSimilarity(
sim_i2t=sim_i2t,
sim_t2i=sim_t2i,
sim_i2t_m=sim_i2t_m,
sim_t2i_m=sim_t2i_m,
sim_i2t_targets=sim_i2t_targets,
sim_t2i_targets=sim_t2i_targets,
),
intermediate_output=AlbefIntermediateOutput(
image_embeds=image_embeds,
image_embeds_m=image_embeds_m,
text_embeds=text_embeds,
text_embeds_m=text_embeds_m,
encoder_output=encoder_output_pos,
encoder_output_neg=encoder_output_neg,
itm_logits=itm_logits,
itm_labels=itm_labels,
),
)
@classmethod
def from_config(cls, cfg=None):
image_encoder = VisionTransformerEncoder.from_config(cfg, from_pretrained=False)
text_encoder = XBertEncoder.from_config(cfg)
embed_dim = cfg.get("embed_dim", 256)
momentum = cfg.get("momentum", 0.995)
alpha = cfg.get("alpha", 0.4)
temp = cfg.get("temp", 0.07)
max_txt_len = cfg.get("max_txt_len", 30)
queue_size = cfg.get("queue_size", 0)
use_distill = cfg.get("use_distill", True)
model = cls(
image_encoder=image_encoder,
text_encoder=text_encoder,
queue_size=queue_size,
embed_dim=embed_dim,
temp=temp,
momentum=momentum,
alpha=alpha,
max_txt_len=max_txt_len,
use_distill=use_distill,
)
model.load_checkpoint_from_config(cfg)
return model
def compute_sim_matrix(self, data_loader, task_cfg):
"""
Compute similarity i2t, t2i matrix for the given data loader.
"""
k_test = task_cfg.k_test
return compute_sim_matrix(model=self, data_loader=data_loader, k_test=k_test)