styledrop / open_clip /coca_model.py
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from typing import Optional
import torch
from torch import nn
from torch.nn import functional as F
import numpy as np
from dataclasses import dataclass
from .transformer import (
LayerNormFp32,
LayerNorm,
QuickGELU,
MultimodalTransformer,
)
from .model import CLIPTextCfg, CLIPVisionCfg, _build_vision_tower, _build_text_tower
try:
from transformers import (
BeamSearchScorer,
LogitsProcessorList,
TopPLogitsWarper,
TopKLogitsWarper,
RepetitionPenaltyLogitsProcessor,
MinLengthLogitsProcessor,
MaxLengthCriteria,
StoppingCriteriaList
)
GENERATION_TYPES = {
"top_k": TopKLogitsWarper,
"top_p": TopPLogitsWarper,
"beam_search": "beam_search"
}
_has_transformers = True
except ImportError as e:
GENERATION_TYPES = {
"top_k": None,
"top_p": None,
"beam_search": "beam_search"
}
_has_transformers = False
@dataclass
class MultimodalCfg(CLIPTextCfg):
mlp_ratio: int = 4
dim_head: int = 64
heads: int = 8
n_queries: int = 256
attn_pooler_heads: int = 8
def _build_text_decoder_tower(
embed_dim,
multimodal_cfg,
quick_gelu: bool = False,
cast_dtype: Optional[torch.dtype] = None,
):
multimodal_cfg = MultimodalCfg(**multimodal_cfg) if isinstance(multimodal_cfg, dict) else multimodal_cfg
act_layer = QuickGELU if quick_gelu else nn.GELU
norm_layer = (
LayerNormFp32 if cast_dtype in (torch.float16, torch.bfloat16) else LayerNorm
)
decoder = MultimodalTransformer(
context_length=multimodal_cfg.context_length,
width=multimodal_cfg.width,
heads=multimodal_cfg.heads,
layers=multimodal_cfg.layers,
ls_init_value=multimodal_cfg.ls_init_value,
output_dim=embed_dim,
act_layer=act_layer,
norm_layer=norm_layer,
)
return decoder
class CoCa(nn.Module):
def __init__(
self,
embed_dim,
multimodal_cfg: MultimodalCfg,
text_cfg: CLIPTextCfg,
vision_cfg: CLIPVisionCfg,
quick_gelu: bool = False,
cast_dtype: Optional[torch.dtype] = None,
pad_id: int = 0,
):
super().__init__()
multimodal_cfg = MultimodalCfg(**multimodal_cfg) if isinstance(multimodal_cfg, dict) else multimodal_cfg
text_cfg = CLIPTextCfg(**text_cfg) if isinstance(text_cfg, dict) else text_cfg
vision_cfg = CLIPVisionCfg(**vision_cfg) if isinstance(vision_cfg, dict) else vision_cfg
self.text = _build_text_tower(
embed_dim=embed_dim,
text_cfg=text_cfg,
quick_gelu=quick_gelu,
cast_dtype=cast_dtype,
)
vocab_size = (
text_cfg.vocab_size # for hf models
if hasattr(text_cfg, "hf_model_name") and text_cfg.hf_model_name is not None
else text_cfg.vocab_size
)
self.visual = _build_vision_tower(
embed_dim=embed_dim,
vision_cfg=vision_cfg,
quick_gelu=quick_gelu,
cast_dtype=cast_dtype,
)
self.text_decoder = _build_text_decoder_tower(
vocab_size,
multimodal_cfg=multimodal_cfg,
quick_gelu=quick_gelu,
cast_dtype=cast_dtype,
)
self.logit_scale = nn.Parameter(torch.ones([]) * np.log(1 / 0.07))
self.pad_id = pad_id
@torch.jit.ignore
def set_grad_checkpointing(self, enable=True):
self.visual.set_grad_checkpointing(enable)
self.text.set_grad_checkpointing(enable)
self.text_decoder.set_grad_checkpointing(enable)
def _encode_image(self, images, normalize=True):
image_latent, tokens_embs = self.visual(images)
image_latent = F.normalize(image_latent, dim=-1) if normalize else image_latent
return image_latent, tokens_embs
def _encode_text(self, text, normalize=True, embed_cls=True):
text = text[:, :-1] if embed_cls else text # make space for CLS token
text_latent, token_emb = self.text(text)
text_latent = F.normalize(text_latent, dim=-1) if normalize else text_latent
return text_latent, token_emb
def encode_image(self, images, normalize=True):
image_latent, _ = self._encode_image(images, normalize=normalize)
return image_latent
def encode_text(self, text, normalize=True, embed_cls=True):
text_latent, _ = self._encode_text(text, normalize=normalize, embed_cls=embed_cls)
return text_latent
def forward(self, image, text, embed_cls=True, image_latent=None, image_embs=None):
text_latent, token_embs = self._encode_text(text, embed_cls=embed_cls)
if image_latent is None or image_embs is None:
image_latent, image_embs = self._encode_image(image)
# TODO: add assertion to avoid bugs?
labels = text[:, -token_embs.shape[1]:]
logits = self.text_decoder(image_embs, token_embs)
return {
"image_features": image_latent,
"text_features": text_latent,
"logits": logits,
"labels": labels,
"logit_scale": self.logit_scale.exp()
}
def generate(
self,
image,
text=None,
seq_len=30,
max_seq_len=77,
temperature=1.,
generation_type="beam_search",
top_p=0.1, # keep tokens in the 1 - top_p quantile
top_k=1, # keeps the top_k most probable tokens
pad_token_id=None,
eos_token_id=None,
sot_token_id=None,
num_beams=6,
num_beam_groups=3,
min_seq_len=5,
stopping_criteria=None,
repetition_penalty=1.0,
fixed_output_length=False # if True output.shape == (batch_size, seq_len)
):
# taking many ideas and components from HuggingFace GenerationMixin
# https://huggingface.co/docs/transformers/main/en/main_classes/text_generation
assert _has_transformers, "Please install transformers for generate functionality. `pip install transformers`."
assert seq_len > min_seq_len, "seq_len must be larger than min_seq_len"
with torch.no_grad():
sot_token_id = 49406 if sot_token_id is None else sot_token_id
eos_token_id = 49407 if eos_token_id is None else eos_token_id
pad_token_id = self.pad_id if pad_token_id is None else pad_token_id
logit_processor = LogitsProcessorList(
[
MinLengthLogitsProcessor(min_seq_len, eos_token_id),
RepetitionPenaltyLogitsProcessor(repetition_penalty),
]
)
if stopping_criteria is None:
stopping_criteria = [MaxLengthCriteria(max_length=seq_len)]
stopping_criteria = StoppingCriteriaList(
stopping_criteria
)
device = image.device
if generation_type == "beam_search":
output = self._generate_beamsearch(
image_inputs = image,
pad_token_id=pad_token_id,
eos_token_id=eos_token_id,
sot_token_id=sot_token_id,
num_beams=num_beams,
num_beam_groups=num_beam_groups,
min_seq_len=min_seq_len,
stopping_criteria=stopping_criteria,
logit_processor=logit_processor,
)
if fixed_output_length and output.shape[1] < seq_len:
return torch.cat(
(output, torch.ones(output.shape[0], seq_len-output.shape[1], device=device, dtype=output.dtype) * self.pad_id),
dim=1
)
return output
elif generation_type == "top_p":
logit_warper = GENERATION_TYPES[generation_type](top_p)
elif generation_type == "top_k":
logit_warper = GENERATION_TYPES[generation_type](top_k)
else:
raise ValueError(
f"generation_type has to be one of "
f"{'| ' + ' | '.join(list(GENERATION_TYPES.keys())) + ' |'}."
)
image_latent, image_embs = self._encode_image(image)
if text is None:
text = torch.ones((image.shape[0], 1), device=device, dtype=torch.long) * sot_token_id
was_training = self.training
num_dims = len(text.shape)
if num_dims == 1:
text = text[None, :]
cur_len = text.shape[1]
self.eval()
out = text
while True:
x = out[:, -max_seq_len:]
cur_len = x.shape[1]
logits = self(image, x, image_latent=image_latent, image_embs=image_embs, embed_cls=False)["logits"][:, -1]
mask = (out[:, -1] == eos_token_id) | (out[:, -1] == pad_token_id)
sample = torch.ones((out.shape[0], 1), device=device, dtype=torch.long) * pad_token_id
if mask.all():
if not fixed_output_length:
break
else:
logits = logits[~mask, :]
filtered_logits = logit_processor(x[~mask, :], logits)
filtered_logits = logit_warper(x[~mask, :], filtered_logits)
probs = F.softmax(filtered_logits / temperature, dim=-1)
if (cur_len + 1 == seq_len):
sample[~mask, :] = torch.ones((sum(~mask), 1), device=device, dtype=torch.long) * eos_token_id
else:
sample[~mask, :] = torch.multinomial(probs, 1)
out = torch.cat((out, sample), dim=-1)
cur_len += 1
if stopping_criteria(out, None):
break
if num_dims == 1:
out = out.squeeze(0)
self.train(was_training)
return out
def _generate_beamsearch(
self,
image_inputs,
pad_token_id=None,
eos_token_id=None,
sot_token_id=None,
num_beams=6,
num_beam_groups=3,
min_seq_len=5,
stopping_criteria=None,
logit_processor=None,
logit_warper=None,
):
device = image_inputs.device
batch_size = image_inputs.shape[0]
image_inputs = torch.repeat_interleave(image_inputs, num_beams, dim=0)
image_latent, image_embs = self._encode_image(image_inputs)
input_ids = torch.ones((batch_size * num_beams, 1), device=device, dtype=torch.long)
input_ids = input_ids * sot_token_id
beam_scorer = BeamSearchScorer(
batch_size=batch_size,
num_beams=num_beams,
device=device,
num_beam_groups=num_beam_groups,
)
# instantiate logits processors
logits_processor = (
LogitsProcessorList([MinLengthLogitsProcessor(min_seq_len, eos_token_id=eos_token_id)])
if logit_processor is None
else logit_processor
)
batch_size = len(beam_scorer._beam_hyps)
num_beams = beam_scorer.num_beams
num_beam_groups = beam_scorer.num_beam_groups
num_sub_beams = num_beams // num_beam_groups
batch_beam_size, cur_len = input_ids.shape
beam_indices = None
if num_beams * batch_size != batch_beam_size:
raise ValueError(
f"Batch dimension of `input_ids` should be {num_beams * batch_size}, but is {batch_beam_size}."
)
beam_scores = torch.full((batch_size, num_beams), -1e9, dtype=torch.float, device=device)
# initialise score of first beam of each group with 0 and the rest with 1e-9. This ensures that the beams in
# the same group don't produce same tokens everytime.
beam_scores[:, ::num_sub_beams] = 0
beam_scores = beam_scores.view((batch_size * num_beams,))
while True:
# predicted tokens in cur_len step
current_tokens = torch.zeros(batch_size * num_beams, dtype=input_ids.dtype, device=device)
# indices which will form the beams in the next time step
reordering_indices = torch.zeros(batch_size * num_beams, dtype=torch.long, device=device)
# do one decoder step on all beams of all sentences in batch
model_inputs = prepare_inputs_for_generation(input_ids=input_ids, image_inputs=image_inputs)
outputs = self(
model_inputs['images'],
model_inputs['text'],
embed_cls=False,
image_latent=image_latent,
image_embs=image_embs
)
for beam_group_idx in range(num_beam_groups):
group_start_idx = beam_group_idx * num_sub_beams
group_end_idx = min(group_start_idx + num_sub_beams, num_beams)
group_size = group_end_idx - group_start_idx
# indices of beams of current group among all sentences in batch
batch_group_indices = []
for batch_idx in range(batch_size):
batch_group_indices.extend(
[batch_idx * num_beams + idx for idx in range(group_start_idx, group_end_idx)]
)
group_input_ids = input_ids[batch_group_indices]
# select outputs of beams of currentg group only
next_token_logits = outputs['logits'][batch_group_indices, -1, :]
vocab_size = next_token_logits.shape[-1]
next_token_scores_processed = logits_processor(
group_input_ids, next_token_logits, current_tokens=current_tokens, beam_group_idx=beam_group_idx
)
next_token_scores = next_token_scores_processed + beam_scores[batch_group_indices].unsqueeze(-1)
next_token_scores = next_token_scores.expand_as(next_token_scores_processed)
# reshape for beam search
next_token_scores = next_token_scores.view(batch_size, group_size * vocab_size)
next_token_scores, next_tokens = torch.topk(
next_token_scores, 2 * group_size, dim=1, largest=True, sorted=True
)
next_indices = torch.div(next_tokens, vocab_size, rounding_mode="floor")
next_tokens = next_tokens % vocab_size
# stateless
process_beam_indices = sum(beam_indices, ()) if beam_indices is not None else None
beam_outputs = beam_scorer.process(
group_input_ids,
next_token_scores,
next_tokens,
next_indices,
pad_token_id=pad_token_id,
eos_token_id=eos_token_id,
beam_indices=process_beam_indices,
)
beam_scores[batch_group_indices] = beam_outputs["next_beam_scores"]
beam_next_tokens = beam_outputs["next_beam_tokens"]
beam_idx = beam_outputs["next_beam_indices"]
input_ids[batch_group_indices] = group_input_ids[beam_idx]
group_input_ids = torch.cat([group_input_ids[beam_idx, :], beam_next_tokens.unsqueeze(-1)], dim=-1)
current_tokens[batch_group_indices] = group_input_ids[:, -1]
# (beam_idx // group_size) -> batch_idx
# (beam_idx % group_size) -> offset of idx inside the group
reordering_indices[batch_group_indices] = (
num_beams * torch.div(beam_idx, group_size, rounding_mode="floor") + group_start_idx + (beam_idx % group_size)
)
input_ids = torch.cat([input_ids, current_tokens.unsqueeze(-1)], dim=-1)
# increase cur_len
cur_len = cur_len + 1
if beam_scorer.is_done or stopping_criteria(input_ids, None):
break
final_beam_indices = sum(beam_indices, ()) if beam_indices is not None else None
sequence_outputs = beam_scorer.finalize(
input_ids,
beam_scores,
next_tokens,
next_indices,
pad_token_id=pad_token_id,
eos_token_id=eos_token_id,
max_length=stopping_criteria.max_length,
beam_indices=final_beam_indices,
)
return sequence_outputs['sequences']
def prepare_inputs_for_generation(input_ids, image_inputs, past=None, **kwargs):
if past:
input_ids = input_ids[:, -1].unsqueeze(-1)
attention_mask = kwargs.get("attention_mask", None)
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_(attention_mask == 0, 1)
else:
position_ids = None
return {
"text": input_ids,
"images": image_inputs,
"past_key_values": past,
"position_ids": position_ids,
"attention_mask": attention_mask,
}