"""
Example code of how to set progress bar using tqdm that is very efficient and nicely looking.

Programmed by Aladdin Persson <aladdin.persson at hotmail dot com>
*    2020-05-09 Initial coding
*    2022-12-19 Updated with more detailed comments, and checked code works with latest PyTorch.

"""

import torch
import torch.nn as nn
from tqdm import tqdm
from torch.utils.data import TensorDataset, DataLoader

# Create a simple toy dataset
x = torch.randn((1000, 3, 224, 224))
y = torch.randint(low=0, high=10, size=(1000, 1))
ds = TensorDataset(x, y)
loader = DataLoader(ds, batch_size=8)


model = nn.Sequential(
    nn.Conv2d(in_channels=3, out_channels=10, kernel_size=3, padding=1, stride=1),
    nn.Flatten(),
    nn.Linear(10 * 224 * 224, 10),
)

NUM_EPOCHS = 10
for epoch in range(NUM_EPOCHS):
    loop = tqdm(loader)
    for idx, (x, y) in enumerate(loop):
        scores = model(x)

        # here we would compute loss, backward, optimizer step etc.
        # you know how it goes, but now you have a nice progress bar
        # with tqdm

        # then at the bottom if you want additional info shown, you can
        # add it here, for loss and accuracy you would obviously compute
        # but now we just set them to random values
        loop.set_description(f"Epoch [{epoch}/{NUM_EPOCHS}]")
        loop.set_postfix(loss=torch.rand(1).item(), acc=torch.rand(1).item())

# There you go. Hope it was useful :)