Hyperparameters are parameters in a machine learning model that are set before training and are not learned during training. Examples of hyperparameters include the learning rate, batch size, number of layers, and number of neurons in each layer. Choosing the right values for these hyperparameters is important for achieving good performance on a given task.
Hyperparameter tuning is the process of selecting the optimal values of hyperparameters for a given model and task. This can be done through a variety of methods, including grid search, random search, and Bayesian optimization. Grid search involves exhaustively searching a predefined range of hyperparameter values, while random search randomly samples hyperparameters from a predefined range. Bayesian optimization uses a probabilistic model to guide the search for optimal hyperparameters.
In addition to hyperparameter tuning, model selection is also an important aspect of building a machine learning model. Model selection involves choosing the best model architecture for a given task, which can involve selecting the number and type of layers, the activation functions used, and other architectural choices.
Model selection can be done through a variety of methods, including manual search, automated search with methods such as neural architecture search, and transfer learning, which involves using pre-trained models as a starting point for a new task.
Overall, hyperparameter tuning and model selection are critical steps in building a successful machine learning model, and a combination of automated and manual methods can be used to achieve the best results.