optuna.study.create_study¶
-
optuna.study.
create_study
(storage=None, sampler=None, pruner=None, study_name=None, direction=None, load_if_exists=False, *, directions=None)[source]¶ Create a new
Study
.Example
import optuna def objective(trial): x = trial.suggest_uniform("x", 0, 10) return x ** 2 study = optuna.create_study() study.optimize(objective, n_trials=3)
- Parameters
storage (Optional[Union[str, optuna.storages._base.BaseStorage]]) –
Database URL. If this argument is set to None, in-memory storage is used, and the
Study
will not be persistent.Note
When a database URL is passed, Optuna internally uses SQLAlchemy to handle the database. Please refer to SQLAlchemy’s document for further details. If you want to specify non-default options to SQLAlchemy Engine, you can instantiate
RDBStorage
with your desired options and pass it to thestorage
argument instead of a URL.sampler (Optional[optuna.samplers._base.BaseSampler]) – A sampler object that implements background algorithm for value suggestion. If
None
is specified,TPESampler
is used during single-objective optimization andNSGAIISampler
during multi-objective optimization. See alsosamplers
.pruner (Optional[optuna.pruners._base.BasePruner]) – A pruner object that decides early stopping of unpromising trials. If
None
is specified,MedianPruner
is used as the default. See alsopruners
.study_name (Optional[str]) – Study’s name. If this argument is set to None, a unique name is generated automatically.
direction (Optional[str]) –
Direction of optimization. Set
minimize
for minimization andmaximize
for maximization.Note
If none of direction and directions are specified, the direction of the study is set to “minimize”.
directions (Optional[Sequence[str]]) – A sequence of directions during multi-objective optimization.
load_if_exists (bool) – Flag to control the behavior to handle a conflict of study names. In the case where a study named
study_name
already exists in thestorage
, aDuplicatedStudyError
is raised ifload_if_exists
is set toFalse
. Otherwise, the creation of the study is skipped, and the existing one is returned.
- Returns
A
Study
object.- Raises
ValueError – If the length of
directions
is zero. Or, ifdirection
is neither ‘minimize’ nor ‘maximize’ when it is a string. Or, if the element ofdirections
is neither minimize nor maximize. Or, if bothdirection
anddirections
are specified.- Return type
See also
optuna.create_study()
is an alias ofoptuna.study.create_study()
.