from collections import OrderedDict
from typing import Callable
from typing import List
from typing import Optional
import optuna
from optuna.distributions import BaseDistribution
from optuna.importance._base import BaseImportanceEvaluator
from optuna.logging import get_logger
from optuna.study import Study
from optuna.trial import FrozenTrial
from optuna.trial import TrialState
from optuna.visualization._plotly_imports import _imports
from optuna.visualization._utils import _check_plot_args
from optuna.visualization._utils import _filter_nonfinite
if _imports.is_successful():
import plotly
from optuna.visualization._plotly_imports import go
logger = get_logger(__name__)
[docs]def plot_param_importances(
study: Study,
evaluator: Optional[BaseImportanceEvaluator] = None,
params: Optional[List[str]] = None,
*,
target: Optional[Callable[[FrozenTrial], float]] = None,
target_name: str = "Objective Value",
) -> "go.Figure":
"""Plot hyperparameter importances.
Example:
The following code snippet shows how to plot hyperparameter importances.
.. plotly::
import optuna
def objective(trial):
x = trial.suggest_int("x", 0, 2)
y = trial.suggest_float("y", -1.0, 1.0)
z = trial.suggest_float("z", 0.0, 1.5)
return x ** 2 + y ** 3 - z ** 4
sampler = optuna.samplers.RandomSampler(seed=10)
study = optuna.create_study(sampler=sampler)
study.optimize(objective, n_trials=100)
fig = optuna.visualization.plot_param_importances(study)
fig.show()
.. seealso::
This function visualizes the results of :func:`optuna.importance.get_param_importances`.
Args:
study:
An optimized study.
evaluator:
An importance evaluator object that specifies which algorithm to base the importance
assessment on.
Defaults to
:class:`~optuna.importance.FanovaImportanceEvaluator`.
params:
A list of names of parameters to assess.
If :obj:`None`, all parameters that are present in all of the completed trials are
assessed.
target:
A function to specify the value to display. If it is :obj:`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. For example, to get the hyperparameter importance of the first
objective, use ``target=lambda t: t.values[0]`` for the target parameter.
target_name:
Target's name to display on the axis label.
Returns:
A :class:`plotly.graph_objs.Figure` object.
"""
_imports.check()
_check_plot_args(study, target, target_name)
layout = go.Layout(
title="Hyperparameter Importances",
xaxis={"title": f"Importance for {target_name}"},
yaxis={"title": "Hyperparameter"},
showlegend=False,
)
# Importances cannot be evaluated without completed trials.
# Return an empty figure for consistency with other visualization functions.
trials = _filter_nonfinite(
study.get_trials(deepcopy=False, states=(TrialState.COMPLETE,)), target=target
)
if len(trials) == 0:
logger.warning("Study instance does not contain completed trials.")
return go.Figure(data=[], layout=layout)
importances = optuna.importance.get_param_importances(
study, evaluator=evaluator, params=params, target=target
)
importances = OrderedDict(reversed(list(importances.items())))
importance_values = list(importances.values())
param_names = list(importances.keys())
importance_labels = [f"{val:.2f}" if val >= 0.01 else "<0.01" for val in importance_values]
fig = go.Figure(
data=[
go.Bar(
x=importance_values,
y=param_names,
text=importance_labels,
textposition="outside",
cliponaxis=False, # Ensure text is not clipped.
hovertemplate=[
_make_hovertext(param_name, importance, study)
for param_name, importance in importances.items()
],
marker_color=plotly.colors.sequential.Blues[-4],
orientation="h",
)
],
layout=layout,
)
return fig
def _get_distribution(param_name: str, study: Study) -> BaseDistribution:
for trial in study.trials:
if param_name in trial.distributions:
return trial.distributions[param_name]
assert False
def _make_hovertext(param_name: str, importance: float, study: Study) -> str:
return "{} ({}): {}<extra></extra>".format(
param_name, _get_distribution(param_name, study).__class__.__name__, importance
)