# optuna.trial¶

The trial module contains Trial related classes and functions.

A Trial instance represents a process of evaluating an objective function. This instance is passed to an objective function and provides interfaces to get parameter suggestion, manage the trial’s state, and set/get user-defined attributes of the trial, so that Optuna users can define a custom objective function through the interfaces. Basically, Optuna users only use it in their custom objective functions.

 optuna.trial.Trial A trial is a process of evaluating an objective function. optuna.trial.FixedTrial A trial class which suggests a fixed value for each parameter. optuna.trial.FrozenTrial Status and results of a Trial. optuna.trial.TrialState State of a Trial. optuna.trial.create_trial Create a new FrozenTrial.