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comet_ml.Optimizer ¶

The Optimizer class. Used to perform a search for minimum or maximum loss for a given set of parameters. Also used for a grid or random sweep of parameter space.

Note that any keyword argument not in the following will be passed onto the Experiment constructor. For example, you can pass project_name and logging arguments by listing them here.

Parameters:

  • config (dict, default: None ) –

    If COMET_OPTIMIZER_ID is configured, otherwise is either a config dictionary, optimizer id, or a config filename.

  • trials (int, default: None ) –

    Number of trials per parameter set to test.

  • verbose (bool, default: 1 ) –

    Verbosity level where 0 means no output, and 1 (or greater) means to show more detail.

  • experiment_class (str | callable, default: 'Experiment' ) –

    Class to use (for example, OfflineExperiment).

Example 
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import comet_ml

comet_ml.login()

# Assume COMET_OPTIMIZER_ID is configured:
opt = comet_ml.Optimizer()

# An optimizer config dictionary:
opt = comet_ml.Optimizer({"algorithm": "bayes", ...})

# An optimizer id:
opt = comet_ml.Optimizer("73745463463")

# A filename to a optimizer config file:
opt = comet_ml.Optimizer("/tmp/mlhacker/optimizer.config")

To pass arguments to the Experiment constructor, pass them into the opt.get_experiments() call, like so:

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import comet_ml

comet_ml.login()
opt = comet_ml.Optimizer("/tmp/mlhacker/optimizer.config")

for experiment in opt.get_experiments(
    project_name="my-project",
    auto_metric_logging=False,
):
    loss = fit(model)
    experiment.log_metric("loss", loss")
    experiment.end()

Functions¶

__init__ ¶

__init__(
    config=None,
    trials=None,
    verbose=1,
    experiment_class="Experiment",
    api_key=None,
    **kwargs
)

The Optimizer constructor.

Parameters:

  • config (str | dict, default: None ) –

    Can an optimizer config id, an optimizer config dictionary, or an optimizer config filename.

  • trials (int, default: None ) –

    Number of trials per parameter value set

  • verbose (int, default: 1 ) –

    Level of details to show; 0 means quiet

  • experiment_class (str | callable, default: 'Experiment' ) –

    Supported values are "Experiment" (the default) to use online Experiments or "OfflineExperiment" to use offline Experiments. It can also be a callable (a function or a method) that returns an instance of Experiment, OfflineExperiment, ExistingExperiment or ExistingOfflineExperiment.

See above for examples.

end ¶

end(experiment)

Optimizer.end() is called at end of experiment. Usually, you would not call this manually, as it is called directly when the experiment ends.

get_experiments ¶

get_experiments(**kwargs)

Optimizer.get_experiments() will iterate over all possible experiments for this sweep or search, n at a time. All experiments will have a unique set of parameter values (unless performing multiple trials per parameter set).

Example 
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import comet_ml

comet_ml.login()
opt = comet_ml.Optimizer({"algorithm": "bayes", ...})

for experiment in opt.get_experiments():
    loss = fit(x, y)
    experiment.log_metric("loss", loss)

get_id ¶

get_id()

Get the id of this optimizer.

Example 
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import comet_ml

comet_ml.login()
opt = comet_ml.Optimizer({"algorithm": "bayes", ...})

opt.get_id()

get_parameters ¶

get_parameters()

Optimizer.get_parameters() will iterate over all possible parameters for this sweep or search. All parameters combinations will be emitted once (unless performing multiple trials per parameter set).

Example 
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import comet_ml

comet_ml.login()
opt = comet_ml.Optimizer({"algorithm": "bayes", ...})

for parameters in optimizer.get_parameters():
    experiment = comet_ml.start()
    loss = fit(x, y)
    experiment.log_metric("loss", loss)

next ¶

next(**kwargs: Dict[str, str]) -> Optional[CometExperiment]

Optimizer.next() will return the next experiment for this sweep or search. All experiments will have a unique set of parameter values (unless performing multiple trials per parameter set).

Normally, you would not call this directly, but use the generator Optimizer.get_experiments()

Parameters:

  • kwargs (Any, default: {} ) –

    Any keyword argument will be passed to the Experiment class for creation. The API key is passed directly.

Example 
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import comet_ml

comet_ml.login()
opt = comet_ml.Optimizer({"algorithm": "bayes", ...})

experiment = optimizer.next()
if experiment is not None:
    loss = fit(x, y)
    experiment.log_metric("loss", loss)

next_data ¶

next_data()

Optimizer.next_data() will return the next parameters in the Optimizer sweep.

Normally, you would not call this directly, but use the generator Optimizer.get_parameters()

Example 
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import comet_ml

comet_ml.login()
opt = comet_ml.Optimizer({"algorithm": "bayes", ...})
experiment = optimizer.next_data()

status ¶

status()

Get the status from the optimizer server for this optimizer.

Example

Running the code sample:

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import comet_ml

comet_ml.login()
opt = comet_ml.Optimizer({"algorithm": "bayes", ...})

opt.status()

Will return the dict:

{
    'algorithm': 'grid',
    'comboCount': 32,
    'configSpaceSize': 10,
    'endTime': None,
    'id': 'c20b90ecad694e71bdb5702778eb8ac7',
    'lastUpdateTime': None,
    'maxCombo': 0,
    'name': 'c20b90ecad694e71bdb5702778eb8ac7',
    'parameters': {
        'x': {
            'max': 20,
            'min': 0,
            'scalingType': 'uniform',
            'type': 'integer'
        }
    },
    'retryCount': 0,
    'spec': {
        'gridSize': 10,
        'maxCombo': 0,
        'metric': 'loss',
        'minSampleSize': 100,
        'randomize': False,
        'retryLimit': 20,
        'seed': 2997936454
    },
    'startTime': 1558793292216,
    'state': {
        'sequence_i': 0,
        'sequence_retry': 11,
        'sequence_trial': 0,
        'total': 32,
    },
    'status': 'running',
    'trials': 1,
    'version': '1.0.0'
}
Nov. 12, 2025