AIM: Autoregressive Image Models

Alaaeldin El-Nouby, Michal Klein, Shuangfei Zhai, Miguel Angel Bautista, Alexander Toshev, Vaishaal Shankar, Joshua M Susskind, and Armand Joulin

This software project accompanies the research paper, Scalable Pre-training of Large Autoregressive Image Models.

We introduce AIM a collection of vision models pre-trained with an autoregressive generative objective. We show that autoregressive pre-training of image features exhibits similar scaling properties to their textual counterpart (i.e. Large Language Models). Specifically, we highlight two findings:

1. the model capacity can be trivially scaled to billions of parameters, and
2. AIM effectively leverages large collections of uncurated image data.

Installation

Please install PyTorch using the official installation instructions. Afterward, install the package as:

pip install git+https://git@github.com/apple/ml-aim.git

We also offer MLX backend support for research and experimentation on Apple silicon. To enable MLX support, simply run:

pip install mlx

Usage

Below we provide an example of usage in PyTorch:

from PIL import Image

from aim.utils import load_pretrained
from aim.torch.data import val_transforms

img = Image.open(...)
model = load_pretrained("aim-600M-2B-imgs", backend="torch")
transform = val_transforms()

inp = transform(img).unsqueeze(0)
logits, _ = model(inp)

and in both MLX

from PIL import Image
import mlx.core as mx

from aim.utils import load_pretrained
from aim.torch.data import val_transforms

img = Image.open(...)
model = load_pretrained("aim-600M-2B-imgs", backend="mlx")
transform = val_transforms()

inp = transform(img).unsqueeze(0)
inp = mx.array(inp.numpy())
logits, _ = model(inp)

and JAX

from PIL import Image
import jax.numpy as jnp

from aim.utils import load_pretrained
from aim.torch.data import val_transforms

img = Image.open(...)
model, params = load_pretrained("aim-600M-2B-imgs", backend="jax")
transform = val_transforms()

inp = transform(img).unsqueeze(0)
inp = jnp.array(inp)
(logits, _), _ = model.apply(params, inp, mutable=['batch_stats'])

Pre-trained checkpoints

The pre-trained models can be accessed either via Hugging Face:

# after running pip install git+https://git@github.com/apple/ml-aim.git
from aim.torch.models import AIMForImageClassification

aim_600m = AIMForImageClassification.from_pretrained("apple/aim-600M")
aim_1b   = AIMForImageClassification.from_pretrained("apple/aim-1B")
aim_3b   = AIMForImageClassification.from_pretrained("apple/aim-3B")
aim_7b   = AIMForImageClassification.from_pretrained("apple/aim-7B")

or PyTorch Hub as:

import torch

aim_600m = torch.hub.load("apple/ml-aim", "aim_600M")
aim_1b   = torch.hub.load("apple/ml-aim", "aim_1B")
aim_3b   = torch.hub.load("apple/ml-aim", "aim_3B")
aim_7b   = torch.hub.load("apple/ml-aim", "aim_7B")

Pre-trained backbones

The following table contains pre-trained backbones used in our paper.

model	#params	attn (best layer)	backbone, SHA256
AIM-0.6B	0.6B	79.4%	link, 0d6f6b8f
AIM-1B	1B	82.3%	link, d254ecd3
AIM-3B	3B	83.3%	link, 8475ce4e
AIM-7B	7B	84.0%	link, 184ed94c

Pre-trained attention heads

The table below contains the classification results on ImageNet-1k validation set.

model	top-1 IN-1k		attention head, SHA256
	last layer	best layer	last layer	best layer
AIM-0.6B	78.5%	79.4%	link, 5ce5a341	link, ebd45c05
AIM-1B	80.6%	82.3%	link, db3be2ad	link, f1ed7852
AIM-3B	82.2%	83.3%	link, 5c057b30	link, ad380e16
AIM-7B	82.4%	84.0%	link, 1e5c99ba	link, 73ecd732

Reproducing the IN-1k classification results

The commands below reproduce the attention probe results on ImageNet-1k validation set. We run the evaluation using 1 node with 8 GPUs:

torchrun --standalone --nnodes=1 --nproc-per-node=8 main_attnprobe.py \
  --model=aim-7B \
  --batch-size=64 \
  --data-path=/path/to/imagenet \
  --probe-layers=last \
  --backbone-ckpt-path=/path/to/backbone_ckpt.pth \
  --head-ckpt-path=/path/to/head_ckpt.pth

By default, we probe the last 6 layers. To change this, simply pass --probe-layers=best.