magma / magma /magma.py
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This should work
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from pathlib import Path
from os.path import exists
import torch
import torch.nn as nn
from copy import deepcopy
from typing import Literal, Optional, List
from torchtyping import TensorType
from transformers.file_utils import ModelOutput
from magma.config import MultimodalConfig
from magma.utils import get_tokenizer
from .language_model import get_gptj
from .adapters import (
Adapter,
ParallelAdapter,
AdapterWrapper,
ParallelAdapterWrapper,
)
from .image_prefix import ImagePrefix
from .sampling import generate
from .utils import build_labels, is_url, print_main, download_checkpoint
from .image_input import ImageInput
from .transforms import get_transforms
# ------------------------- Magma main class ----------------------------------
class Magma(nn.Module):
def __init__(self, config, device=None):
super().__init__()
if isinstance(config, (str, Path)):
config = MultimodalConfig.from_yml(
config
) # load config from yml file if config is a string
else:
assert isinstance(config, MultimodalConfig)
self.device = device or torch.device(
"cuda" if torch.cuda.is_available() else "cpu"
)
self.config = config
self.lm = get_gptj().to(self.device)
self.seq_len = self.lm.config.max_position_embeddings
self.tokenizer = get_tokenizer("gpt2", sequence_length=self.seq_len)
self.image_token = self.tokenizer.cls_token_id
self.eos_token = self.tokenizer.eos_token_id
self.lm.resize_token_embeddings(len(self.tokenizer))
self.lm.config.pad_token_id = self.tokenizer.eos_token_id
self.word_embedding = self.lm.transformer.wte.to(device)
self.transformer = self.lm.transformer.h
# adapter settings
self.mlp_adapter_added, self.attn_adapter_added = False, False
self.image_prefix = ImagePrefix(
config=config,
out_dim=self.lm.config.hidden_size,
).to(self.device)
# might change based on the type of image encoder, so get from prefix instead of config
self.image_prefix_seq_len = self.image_prefix.out_seq_len
self.transforms = get_transforms(
config.image_size,
config.encoder_name,
input_resolution=self.image_prefix.enc.input_resolution,
)
# add adapters
if config.adapter_config:
mlp_config = deepcopy(config.adapter_config.get("mlp", None))
if mlp_config:
assert mlp_config.get("adapter_type") is not None
self.add_adapters(
location="mlp",
adapter_type=mlp_config.pop("adapter_type"),
downsample_factor=mlp_config.pop("downsample_factor", 4),
**mlp_config,
)
attn_config = deepcopy(config.adapter_config.get("attention", None))
if attn_config:
assert attn_config.get("adapter_type") is not None
self.add_adapters(
location="attention",
adapter_type=attn_config.pop("adapter_type"),
**attn_config,
)
# freeze parameters
if config.freeze_lm:
for name, param in self.lm.named_parameters(): # freeze lm weights
if config.adapter_config and "adapter" in name:
param.requires_grad = True
if config.freeze_img_encoder:
for param in self.image_prefix.enc.parameters():
param.requires_grad = False
def add_adapters(
self,
downsample_factor: int = 4,
adapter_type: Literal["normal", "parallel", "scaled_parallel"] = "normal",
location: Literal["mlp", "attention"] = "mlp",
ff_attr: str = "mlp",
attn_attr: str = "attn",
**adapter_kwargs,
):
"""
Adds an adapter layer to `self` at the specified location
"""
assert adapter_type in [
"normal",
"parallel",
"scaled_parallel",
], "adapter_type must be one of 'normal', 'parallel', or 'scaled_parallel'"
assert location in [
"mlp",
"attention",
], "location must be one of 'mlp' or 'attention'"
for l in range(len(self.transformer)):
if location == "mlp":
if self.mlp_adapter_added:
raise ValueError("Adapter layer already added")
mlp = getattr(self.transformer[l], ff_attr)
if adapter_type in ["parallel", "scaled_parallel"]:
adapter_layer = ParallelAdapter(
module=mlp,
dim=self.lm.config.hidden_size,
downsample_factor=downsample_factor,
scaled=adapter_type == "scaled_parallel",
**adapter_kwargs,
)
else:
adpt = Adapter(
dim=self.lm.config.hidden_size,
downsample_factor=downsample_factor,
**adapter_kwargs,
)
adapter_layer = nn.Sequential(
*[
mlp,
adpt,
]
)
setattr(self.transformer[l], ff_attr, adapter_layer)
else:
if self.attn_adapter_added:
raise ValueError("Adapter layer already added")
attn = getattr(self.transformer[l], attn_attr)
if adapter_type in ["parallel", "scaled_parallel"]:
adapter_layer = ParallelAdapterWrapper(
module=attn,
dim=self.lm.config.hidden_size,
downsample_factor=downsample_factor,
scaled="scaled" in adapter_type,
**adapter_kwargs,
)
else:
adapter_layer = AdapterWrapper(
attn_block=attn,
dim=self.lm.config.hidden_size,
downsample_factor=downsample_factor,
**adapter_kwargs,
)
setattr(self.transformer[l], attn_attr, adapter_layer)
if location == "mlp":
self.mlp_adapter_added = True
else:
self.attn_adapter_added = True
def preprocess_inputs(self, input_list: list, embed = True) -> List[torch.Tensor]:
"""
Expects a list of strings and instances of ImageInput
Converts them into a list of tensors and then optionally runs self.embed over it
"""
for i in range(len(input_list)):
inp = input_list[i]
if isinstance(inp, str):
input_list[i] = self.tokenizer.encode(inp, return_tensors="pt")
elif isinstance(inp, ImageInput):
input_list[i] = inp.get_transformed_image(transform_fn = self.transforms)
else:
raise Exception(f'Invalid input type:{type(inp)}')
if embed == True:
return self.embed(input_list)
else:
return input_list
def embed(self, inputs: List[torch.Tensor]) -> TensorType["b", "s", "d"]:
"""
Embeds a list of tensors In the correct format to input into the LM (b, s, d).
For each tensor, if it's 2d assume it's text and use word embedding,
if it's 4d, assume it's an image, and use image_prefix to embed.
"""
emb_list = []
for x in inputs:
if x.ndim == 2:
x = x.to(self.device)
emb_list.append(self.word_embedding(x))
elif x.ndim == 4:
x = x.to(self.device).half()
image_embeddings = self.image_prefix(x)
emb_list.append(image_embeddings)
else:
raise ValueError(f"Expected 2d or 4d tensor, got {x.ndim}d")
return torch.cat(emb_list, dim=1)
@torch.no_grad()
def generate(
self,
embeddings: TensorType["b", "s", "d"],
max_steps: int = 100,
temperature: float = 0.7,
top_k: int = 0,
top_p: float = 0.9,
decode: bool = True,
):
"""
Generates captions for a batch of embeddings.
"""
return generate(
self,
embeddings=embeddings,
max_steps=max_steps,
temperature=temperature,
top_k=top_k,
top_p=top_p,
decode=decode,
)
def forward(
self,
images: TensorType["b", "c", "h", "w"] = None,
captions: Optional[TensorType["b", "seq"]] = None,
output_hidden_states: bool = False,
input_embeddings: TensorType["b", "s", "d"] = None,
) -> ModelOutput:
assert captions is not None, "Must provide captions in training"
assert any([i is not None for i in [images, input_embeddings]]) and not all(
[i is not None for i in [images, input_embeddings]]
), "Pass in either images, or input embeddings, not both."
assert (
captions.shape[1] == self.seq_len
), f"in training, captions should be padded to sequence length ({self.seq_len}), but are length {captions.shape[1]}"
if input_embeddings is None:
input_embeddings = self.image_prefix(images)
labels = build_labels(
input_embeddings, captions, self.eos_token, self.device
) # build labels from input_embeddings
word_embeddings = self.word_embedding(captions)
# join together
input_embeddings = torch.cat(
(
input_embeddings,
word_embeddings[:, : -input_embeddings.shape[1], :],
), # remove padding in the word embedding before concatenating
dim=1,
)
# forward joined embeddings through lm
lm_outputs = self.lm(
inputs_embeds=input_embeddings,
labels=labels,
output_hidden_states=output_hidden_states,
)
return lm_outputs
@classmethod
def from_checkpoint(cls, config_path, checkpoint_path, device = 'cpu'):
"""
Loads a model checkpoint from disk / downlods from url if not present
"""
checkpoint_url = 'https://drive.google.com/u/0/uc?id=1EiAY3IcKWmGADaLDzdG25ykQghUwza6L&export=download'
if exists(checkpoint_path) == False:
print_main(f'checkpoint: {checkpoint_path} does not exist, downloading model')
download_checkpoint(checkpoint_url = checkpoint_url, save_as = checkpoint_path)
model = cls(config = config_path)
sd = torch.load(checkpoint_path, map_location=torch.device("cpu"))
if "module" in sd.keys():
sd = sd["module"]
print_main('loading checkpoint magma')
model.load_state_dict(sd, strict=False)
print_main("magma model successfully loaded")
model.half().to(device)
return model