optuna.visualization.plot_contour¶

optuna.visualization.plot_contour(study: optuna.study.Study, params: Optional[List[str]] = None, *, target: Optional[Callable[[optuna.trial._frozen.FrozenTrial], float]] = None, target_name: str = 'Objective Value') → plotly.graph_objs._figure.Figure[source]¶

Plot the parameter relationship as contour plot in a study.

Note that, If a parameter contains missing values, a trial with missing values is not plotted.

Example

The following code snippet shows how to plot the parameter relationship as contour plot.

import optuna


def objective(trial):
    x = trial.suggest_uniform("x", -100, 100)
    y = trial.suggest_categorical("y", [-1, 0, 1])
    return x ** 2 + y


sampler = optuna.samplers.TPESampler(seed=10)
study = optuna.create_study(sampler=sampler)
study.optimize(objective, n_trials=30)

optuna.visualization.plot_contour(study, params=["x", "y"])

Parameters

study – A Study object whose trials are plotted for their target values.
params – Parameter list to visualize. The default is all parameters.
target –
A function to specify the value to display. If it is None and study is being used for single-objective optimization, the objective values are plotted.

Note

Specify this argument if study is being used for multi-objective optimization.
target_name – Target’s name to display on the color bar.

Returns

A plotly.graph_objs.Figure object.

Raises

ValueError – If target is None and study is being used for multi-objective optimization.