model.py

import torch
import torchvision

from torch import nn


def create_effnetb2_model(num_classes: int = 3,  # default output classes = 3 (pizza, steak, sushi)
                          seed: int = 42):
    # 1, 2, 3 Create EffNetB2 pretrained weights, transforms and model
    weights = torchvision.models.EfficientNet_B2_Weights.DEFAULT
    transforms = weights.transforms()
    model = torchvision.models.efficientnet_b2(weights=weights)

    # 4. Freeze all layers in the base model
    for param in model.parameters():
        param.requires_grad = False

    # 5. Change classifier head with random seed for reproducibility
    torch.manual_seed(seed)
    model.classifier = nn.Sequential(
        nn.Dropout(p=0.3, inplace=True),
        nn.Linear(in_features=1408, out_features=num_classes)
    )

    return model, transforms