zero_shot_prediction.py

import torch
import clip
import os

from PIL import Image
from torchvision.datasets import CIFAR100


if __name__ == "__main__":
    import argparse
    
    parser = argparse.ArgumentParser()
    
    parser.add_argument("--pt", type=str, help="模型名称")
    
    args = parser.parse_args()
    
    device = "cuda" if torch.cuda.is_available() else "cpu"
    
    if ".pt" in args.pt:
        model, preprocess = clip.load(f"pretrained_models/{args.pt}", device=device)
    else:
        model, preprocess = clip.load(f"{args.pt}", device=device)
        
    # Download the dataset
    cifar100 = CIFAR100(root=os.path.expanduser("~/.cache"), download=True, train=False)

    # Prepare the inputs
    image, class_id = cifar100[3637]
    image_input = preprocess(image).unsqueeze(0).to(device)
    text_inputs = torch.cat([clip.tokenize(f"a photo of a {c}") for c in cifar100.classes]).to(device)

    # Calculate features
    with torch.no_grad():
        image_features = model.encode_image(image_input)
        text_features = model.encode_text(text_inputs)

    # Pick the top 5 most similar labels for the image
    image_features /= image_features.norm(dim=-1, keepdim=True)
    text_features /= text_features.norm(dim=-1, keepdim=True)
    similarity = (100.0 * image_features @ text_features.T).softmax(dim=-1)
    values, indices = similarity[0].topk(5)

    # Print the result
    print("\nTop predictions:\n")
    for value, index in zip(values, indices):
        print(f"{cifar100.classes[index]:>16s}: {100 * value.item():.2f}%")