> For the complete documentation index, see [llms.txt](https://avalanche.continualai.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://avalanche.continualai.org/avalanche-v0.1.0/examples/training.md).

# Training

{% code title="" %}

```python
model = SimpleMLP(hidden_size=args.hs)
optimizer = torch.optim.SGD(model.parameters(), lr=args.lr)
criterion = torch.nn.CrossEntropyLoss()

# check if selected GPU is available or use CPU
assert args.cuda == -1 or args.cuda >= 0, "cuda must be -1 or >= 0."
if args.cuda >= 0:
    assert torch.cuda.device_count() > args.cuda,
    f"{args.cuda + 1} GPU needed. Found {torch.cuda.device_count()}."
device = 'cpu' if args.cuda == -1 else f'cuda:{args.cuda}'
print(f'Using device: {device}')

# create split scenario
scenario = SplitMNIST(n_experiences=5, return_task_id=False)

interactive_logger = InteractiveLogger()
eval_plugin = EvaluationPlugin(
    accuracy_metrics(minibatch=True, epoch=True, experience=True, stream=True),
    loss_metrics(minibatch=True, epoch=True, experience=True, stream=True),
    ExperienceForgetting(),
    loggers=[interactive_logger])

# create strategy
assert len(args.lwf_alpha) == 1 or len(args.lwf_alpha) == 5,
'Alpha must be a non-empty list.'
lwf_alpha = args.lwf_alpha[0] if len(args.lwf_alpha) == 1 else args.lwf_alpha

strategy = LwF(model, optimizer, criterion, alpha=lwf_alpha,
               temperature=args.softmax_temperature,
               train_epochs=args.epochs, device=device,
               train_mb_size=args.minibatch_size, evaluator=eval_plugin)

# train on the selected scenario with the chosen strategy
print('Starting experiment...')
results = []
for train_batch_info in scenario.train_stream:
    print("Start training on experience ", train_batch_info.current_experience)

    strategy.train(train_batch_info, num_workers=4)
    print("End training on experience ", train_batch_info.current_experience)
    print('Computing accuracy on the test set')
    results.append(strategy.eval(scenario.test_stream[:]))
```

{% endcode %}

## 🤝 Run it on Google Colab

You can run *this chapter* and play with it on Google Colaboratory:

{% hint style="danger" %}
Notebook currently unavailable.
{% endhint %}


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